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doi:10.1111/jog.12471
J. Obstet. Gynaecol. Res. Vol. 40, No. 12: 2191–2200, December 2014
Predictors and incidence of post-partum depression: A longitudinal cohort study Fatemeh Abdollahi1, Mehran Zarghami2,3, Md Zain Azhar4, Shariff-Ghazali Sazlina5 and Munn-Sann Lye6 1
Public Health Department, Faculty of Health, 2Psychiatry and Behavioral Sciences Research Center, Addiction Institute, and Department of Psychiatry, Mazandaran University of Medical Sciences, Sari, Iran; 4Department of Psychiatry, 5Department of Family Medicine, and 6Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia 3
Abstract Aim: This study was designed to identify the incidence and the related factors contributing to post-partum depression (PPD) in women in Iran for the first time. Material and Methods: A total of 2279 eligible pregnant women from 32–42 weeks of pregnancy to 12 weeks post-partum (2009) who attended primary health centers in Mazandaran province were screened for depression using the Iranian version of the Edinburgh Postnatal Depression Scale. Pregnant women free from depression were assessed using validated questionnaires, including the Premenstrual Syndrome Questionnaire, Social Support Appraisal Scale, Network Orientation Scale, General Health Questionnaire, Marital Inventory, Life Events Rating Scale and Parental Expectation Survey. Logistic regression analysis was used to determine the risk factors of PPD. Results: Of 1801 women who screened negative for depression at 32–42 weeks’ gestation, cumulative incidence proportions were 6.7%, 4.3% and 4.5% during 0–2, >2–8 and >8–12 weeks post-partum, respectively. The factors predictive of PPD were: history of depression during the first two trimesters of pregnancy (odds ratio [OR] = 2.55, 95% confidence interval [CI] = 1.59–4.1); psychiatric disorder during pregnancy (OR = 1.08, 95%CI = 1.06–1.11); gestational diabetes (OR = 2.93, 95%CI = 1.46–5.88); recurrent urinary infection (OR = 2.25, 95%CI = 1.44–3.52); unwanted pregnancy (OR = 2.5, 95%CI = 1.69–3.7) and low household income (OR = 3.57, 95%CI = 1.49–8.5). The risk was decreased with increasing age (OR = 0.88, 95%CI = 0.84–0.92) and those with high self-efficacy for mothering (OR = 0.7, 95%CI = 0.62–0.78). Conclusion: A high rate of new cases of PPD was identified in Iranian women. A combination of psychological, sociological, obstetric and sociodemographic factors can render mothers vulnerable to post-partum depression. Key words: depression, incidence, reproductive health, risk factors.
Introduction The World Health Organization has estimated that by 2020, major depressive disorder (MDD) would constitute the second largest component of the burden of disease worldwide.1 One of the subtypes of MDD rec-
ognized by the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV-TR) is post-partum depression (PPD).2 Globally, the prevalence of PPD can be as high as 60% in some countries,3 while in Iran it varies between 20.3% and 35%.4–7 The limited number of available studies on the incidence of PPD reported
Received: October 12 2013. Accepted: April 13 2014. Reprint request to: Professor Munn-Sann Lye, Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Malaysia. Email: [email protected]
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that 6.5% of mothers develop a new episode of depression during the first 3 months after birth.8 There is a three-fold increase in the risk of depression during 3–6 months following birth compared to other times of life.9 PPD affects all aspects of a woman’s life, including her relationship with her partner and her child’s development.9–11 It also affects a woman’s mental health in the long term,12 and negatively affects all areas of quality of life from physical to social functioning.13 Disorders in cognitive, emotional and social development are more common in children of mothers with PPD.14–16 Conclusions from studies on the cause of PPD have been inconsistent.8,17,18 Numerous causes have been suggested; however, no single hypothesis is able to elucidate this phenomenon.8,19 Cultural aspects also play a fundamental role in the way motherhood is perceived and experienced in different cultures.20,21 Most of the rigorous studies on PPD so far have been conducted in Western countries and reliable data are relatively lacking for Asian populations.20,21 Also, not many studies captured incidence data, which have inherently greater validity in supporting causal inference for the risk of developing PPD. This study was carried out to determine demographic, sociological, psychological, cultural, obstetric, gynecological and possible hormone-related factors that are involved in the development of post-partum depression in a longitudinal follow-up study in the Iranian population for the first time.
Methods In this cohort follow-up study, 2279 pregnant women, literate in Persian, at the gestational stage of 32–42 weeks, who attended prenatal care at urban and rural primary health centers (PHC) of Mazandaran University of Medical Sciences (MAZUMS) in Mazandran Province in northern Iran from January to June 2009 were recruited. Women who were depressed during 32–42 weeks of pregnancy according to the Edinburgh Postnatal Depression Scale (EPDS)22 or who were on pharmacological treatment for psychiatric problems were excluded. Mothers who were found to have depression based on the EPDS and who were in need of specialized assistance regarding prevention or early treatment were referred to a physician for treatment. The potential risk factors (indicators) before and during pregnancy and at delivery were utilized in estimating the risk of PPD over 12 weeks post-partum. Cumula-
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tive incidence proportions were computed for the periods 0–2, >2–8 and >8–12 weeks post-partum. Written consent was obtained from women with the assurance of confidentiality of information given. The study was approved by the Faculty of Medicine and Health Sciences Medical Research Ethics Committee, University Putra Malaysia and Ethics Committee of Mazandaran University of Medical Sciences in Iran. Validated instruments that were used in this study included the Premenstrual Syndrome Questionnaire (PMSQ),23 Social Support Appraisals Scale (SSA),24 Network Orientation Scale (NOS),25 General Health Questionnaire (GHQ-28),26 Marital Inventory (ENRICH),27 Life Events Rating Scale (LERS),28 Parental Expectation Survey (PES)29 and EPDS.22 Standard questionnaires were used for other information. Demographic characteristics included mother’s age, marital age, marital status, parity, maternal education, mother’s and father’s employment and total household income. Information on mental health included previous PPD, family history of depression, depression during first and second trimester of pregnancy and anxiety during pregnancy. Hormone-related conditions included irritable moods before menstruation, mood instability secondary to oral contraception and mood instability at puberty period. Psychosocial data included life events, social support, marital relationship, parental selfefficacy and abuse. Obstetric and gynecological data included pregnancy wantedness, mode of delivery, sex of baby, history of abortion or stillbirth, the gestational age at first antenatal care, the number of antenatal care visits, place of delivery and any complication during pregnancy. Rituals and customs after childbirth included information on behavior, such as having 42 days of rest after childbirth, giving a party and eating traditional food. PMSQ,30 SSA,31 GHQ,32 ENRICH,33 LERS34 and EPDS5 have been used before in the Iranian population, and their validity in the Persian language have been established. Questionnaires for sociodemographic information that have not been used before in Iran were translated into Persian, and back-translated for verification. The internal consistency of the PES and NOS as measured by Cronbach’s alpha was 0.59 and 0.91, respectively. The content validity of all questionnaires was tested by 10 experts in the Psychiatry and Behavioral Sciences Research Center of Mazandaran University of Medical Sciences. All questionnaires were used after pretesting with a sample of 60 healthy unselected pregnant women in PHC (Cronbach’s alpha ranged between 0.42 and 0.92).
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
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The EPDS is the most widely used screening tool to detect mothers who are suffering from PPD.35 We used the Iranian version of EPDS, which consists of 10 items relating to mood. Each item is scored from 0 to 3 with four responses (‘no, not at all, quite often, yes’) on the severity of symptoms during the past week. The total score was calculated by computing the scores for each of 10 items with seven (items 3, 5, 6, 7, 8, 9, 10) of the 10 items being scored reversely.35,36 Studies in Iran showed a score of greater than 12 was a valid cut-off value for the provisional diagnosis of PPD with 95% sensitivity and 93% specificity.4,5 A higher score for PES and MI indicates better parental self-efficacy and marital relationship, while a lower score for GHQ, PMSQ, SSA, NOS and LERS indicates better health status, social support as well as fewer adverse life events. The women were categorized in two groups. One category included mothers who obtained scores above the EPDS threshold level of 12 at each follow-up time period: 0–2, >2–8, and >8–12 weeks post-partum. The other category, a reference category, included mothers who received scores less than the cut-off point. Simple logistic regression was used to determine the putative effect of each potential risk factor on PPD. Variables that were statistically significant in the univariate analysis were then examined in a hierarchical multiple logistic regression. Based on literature review and theory of post-partum depression, variables were entered into the model in the following sequential order to obtain adjusted odds ratios: mental health, psychosocial, obstetric and gynecological, sociodemographic, and hormone-related factors.
Results During the study period, 2626 women were eligible for the study and 2359 (89.9%) volunteered to participate. Of those, 2279 (96.6%) completed the EPDS and other questionnaires. A total of 478 (21%) women whose EPDS scores were more than the threshold of 12 during the third trimester or who were on medication for psychiatric disorders were excluded from the study. The remaining 1801 (79%) mothers were followed up to ascertain incident cases of PPD during the periods 0–2, >2–8 and >8–12 weeks post-partum. Response rates during 0–2, >2–8 and >8–12 weeks post-partum were 96.6% (1739/1801), 93.3% (1622/1739) and 94.4% (1531/1622), respectively. Overall, 254 (14.10 %) mothers were found to have EPDS greater than 12 over
this 12-week period and were compared with mothers who were not depressed (1292) over the same 12-week period. A comparison was made between pregnant women who participated in the study but did not complete the study (255; 14.15%) and the women who completed the study (1546; 85.84%) and found no significant difference in terms of the average age, women’s and their husbands’ education, experience of depression, anxiety during pregnancy and previous post-partum depression as well as the mean EPDS scores during the third trimester. The mean age and age at marriage of these women were 25.9 ± 5.2 years and 20.4 ± 4 years, respectively. More than 60% of women were primigravidae and half of them and their husbands’ education were less than high school (50.5% and 41.3%, respectively). About half of them (50.6%) were recruited from rural PHC. The majority of women (60.1%) had fewer than nine prenatal visits (mean = 9.3 ± 3.6). About half of the babies (53.9%) were born vaginally. Approximately 42 (2%) mothers stated having PPD in previous pregnancies. Two hundred fifty-two mothers (14%) described having irritable mood prior to menstruation. A total of 178 (9.9%) had a history of depression in the first and second trimesters, while 780 (43.3%) experienced anxiety. The mean scores of social support and social isolation based on SSA, NOS, MS, PSE and mean number of LE were 47.24 ± 4.91, 47.81 ± 4.36, 25.05 ± 3.61, 7.96 ± 1.49 and 2.81 ± 2.73. About 12.21% of the women reported at least one kind of abuse. The number of cultural practices ranged from zero to 27 with a mean of 14.13 ± 3.9. The incidence proportions of depression occurring in the post-partum periods of 0–2, >2–8 and >8–12 weeks post-partum were 6.9% (120/1739), 4.6% (69/ 1509), and 4.8% (65/1357), respectively. PPD incidence during the study at each period of data collection is shown in Figure 1. Tables 1 and 2 describe the frequency and percentage for post-partum depression by each category of the significant variables, univariate odds ratio (OR) with 95% confidence interval (CI), and P-values, based on EPDS score. A total of 1449 mothers were available for analysis. Hierarchical multiple logistic regression showed that there was increased odds of PPD with lower state of general health (OR = 1.08 [95%CI: 1.06–1.11]), being depressed during first and second trimester of
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Participating mothers from 32 weeks’ pregnancy to term, 2359
Total number of mothers who completed first EPDS questionnaire 2279, 80 (3.4%) missing
1801 (71%) mothers’ EPDS ≤ 12 from 32 weeks’ pregnancy to term
2 weeks after birth, 1739 followed up, 62 (3.4%) dropouts
120
1619
8 weeks after birth, 1622 followed up, 117 (6.7%) dropouts
Dropouts 1440
69
Dropouts
51
110
Dropouts
62
7
Dropouts Dropouts
1292
65
83
30
36
3
34
13
4
26
Dropouts
35
1
12 weeks after birth, 1531 followed up, 91 (5.6%) dropouts Figure 1 Incidence of post-partum depression in 1801 women who had Edinburgh Postnatal Depression Scale (EPDS) ≤ 12 from 32 weeks’ gestation to term and followed until 12 weeks post-partum. ( ) EPDS > 12. (□) EPDS ≤ 12.
pregnancy (OR = 2.55 [95%CI: 1.59–4.1]), experienced recurrent urinary infection (OR = 2.25 [95%CI: 1.44– 3.52]), unwanted pregnancy (OR = 2.5, [95%CI: 1.69– 3.7]), gestational diabetes (OR = 2.93 [95%CI =
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1.46–5.88]) and household income (OR = 3.57 [95%CI: 1.49–8.5]). The odds of PPD decreased with sufficient parenting skills (OR = 0.7, [95%CI: 0.62–0.78]) and among older mothers (OR = 0.88 [95%CI: 0.84–0.92]).
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
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Table 1 Sociodemographic and obstetric and gynecological factors associated with depression over 12 weeks post-partum using simple logistic regression (n = 1546) Risk factors
B
B(SE)
Odds ratio
95%CI
P-value
Age (years) Age at marriage (years) Education (years) Total household income (tomans, monthly) Low (less than 350 000)† Medium (350 000–450 000) High (more than 450 000) Gravida Family structure Extend Nuclear Occupation Housewife Employed Anemia Yes No Gestational diabetes Yes No Recurrent urinary infection Yes No Reason for sick leave Pregnancy related Miscellaneous Planned pregnancy Not planned Planned Unknown neonatal complications Yes No Infection Yes No
−0.06 −0.03 −0.04
0.01 0.01 0.02
0.94 0.96 0.95
0.91–0.96 0.93–0.99 0.91–0.99
0.001 0.04 0.02 0.002
0.78 0.44
0.25 0.28
1.32–3.6 0.89–2.73
−0.24
0.09
2.18 1.56 1 0.78
0.56–0.93
0.006
0.3
0.14
1.35 1
1.01–1.8
0.04
1.24
0.46
3.46 1
1.39–8.62
0.008
0.44
0.21
1.55 1
1.03–2.35
0.03
0.78
0.28
2.19 1
1.26–3.8
0.005
0.71
0.19
2.04 1
1.41–2.96
0.001
−1.33
0.59
0.26 1
0.08–0.85
0.02
0.4
0.16
1.5 1
1.09–2.06
0.01
0.66
0.33
1.94
1.01–3.72
0.04
0.75
0.31
2.13 1
1.15–3.94
0.01
†Toman: 10 rials = 1 Toman = 0.01 USD. CI, confidence interval.
Table 3 shows B coefficient estimates and the corresponding OR indicating the independent effect of each variable controlling for the effect of other variables in the model.
Discussion Prevalence and incident measurements are important for identifying health problems and disease burden.37 Although the incidence rate is a unique and significant finding from both academic and clinical perspectives, few studies have actually investigated it. What makes
comparison with other studies difficult is the variation in the timing of post-partum follow-up. Gaynes et al. reported that about 6.5% of women developed a new episode during the first month post-partum,38 which is consistent with our findings. In this study, there was a slight decrease in PPD incidence from 6.9% for weeks 0–2 to 4.8% for weeks >8–12 post-partum. In longitudinal studies, the EPDS with the same cut-off value was used by Evens et al. in the UK and by Escriba-Aguir et al. in Spain.39,40 They reported a decrease in the incidence rates over the first post-partum year from 5.31% and 9.3% to 2.61% and 4.4%, respectively.39,40
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Table 2 Psychological and psychosocial factors associated with depression over 12 weeks post-partum using simple logistic regression (n = 1546) Risk factors Depression in 1st/2nd trimesters of pregnancy Yes No Anxiety in pregnancy Yes No Family history of depression Yes No General health status Not healthy (>21) Healthy (≤21) Social support during pregnancy Low (≥51) Medium (45–50) High (≤44) Social isolation during pregnancy Low (≥51) Medium (45–50) High (≤44) Number of life events ≥4 2–3 ≤1 Postnatal parenting self-efficacy Low (≤7) Medium (7.01–8.91) High (≥9)
B
B(SE)
Odds ratio
95%CI
P-value
0.71
0.19
2.04 1
1.39–3.01
0.001
0.5
0.13
1.65 1
1.26–2.17
0.001
0.58
0.24
1.79 1
1.1–2.91
0.01
0.7
0.13
2.02 1
1.54–2.65
0.001
0.45 0.2
0.19 0.17
1.58 1.22 1
1.08–2.3 0.87–1.71
0.01 0.23
0.42 0.13
0.18 0.17
1.53 1.13 1
1.06–2.19 0.81–1.58
0.02 0.44
0.4 0.11
0.16 0.17
1.49 1.12 1
1.08–2.05 0.8–1.58
0.01 0.49
0.67 0.004
0.18 0.17
1.96 1.004 1
1.36–2.84 0.71–1.41
0.001 0.98
CI, confidence interval.
Table 3 Risk of post-partum depression over 12 weeks post-partum using hierarchical multiple logistic regression (n = 1449) Risk factors
Adjusted odds ratio
95%CI
P-value
General health status Depression in 1st/2nd trimester Postnatal parenting self-efficacy Unwanted pregnancy Recurrent urinary infection Gestational diabetes Mother’s age Household income: Low vs high Medium vs high
1.08 2.55 0.7 2.5 2.25 2.93 0.88
1.06–1.11 1.59–4.1 0.62–0.78 1.69–3.7 1.44–3.52 1.46–5.88 0.84–0.92
0.001 0.001 0.001 0.001 0.001 0.002 0.001
3.57 1.72
1.49–8.5 0.66–4.48
0.004 0.26
CI, confidence interval.
Two strong predictors of post-partum depression in this study were psychological distress (using GHQ) during 32–42 weeks of gestation, and depression in the first and second trimesters of pregnancy. These find-
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ings were consistent with a longitudinal study among 5262 Danish women by Nielson et al. who found a similar association between GHQ scores during late pregnancy and PPD at the fourth month post-partum.41
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
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Other studies also showed that women with PPD were most likely to have psychological symptoms during pregnancy.42,43 Three meta-analyses and additional studies regarding risk factors for PPD on 24 000 subjects concluded that having depression and anxiety during pregnancy and previous history of psychiatric illness are strong risk factors for developing PPD.11 This study also found that a lack of postnatal parental competence and low parenting self-efficacy were significant risk factors for PPD. Several studies have demonstrated that the stresses of child care play significant roles in PPD.7,11,44,45 Women who have a positive view of their maternal capabilities were found to be more able to care for the infant with confidence immediately after birth.46 Huang and Mathers reported that Taiwanese mothers who had problems in adapting to the role of motherhood had higher scores on EPDS.47 It is possible that these mothers experienced more stress when they began to care for the baby or were not being prepared for motherhood during their pregnancy.48,49 A woman’s mental health could be challenged by unwanted pregnancy and post-partum complications. This study and other studies concluded that the PPD is more prevalent among mothers with unwanted pregnancies.50,51 Unwanted pregnancy can cause adverse physical, psychological and social consequences in the short- and long-term for the women52,53 and affect the mothers’ feelings towards their fetus, as well as towards others involved.11 Few studies have looked specifically at the association between recurrent urinary infection in pregnancy and post-partum depression. In this study, women with urinary tract infection during pregnancy had increased risk of PPD (OR = 2.25; 95%CI = 1.44–3.52). This finding is also supported by Hullfish et al.,54 but it is not clear how urgency and urinary incontinence could have increased the risk of PPD. Perhaps women who have these problems may be too embarrassed to talk about them, further heightening stress levels contributing to PPD. Women with gestational diabetes in this study had almost threefold the odds of PPD compared with women who did not. Consistent with this study, Kozhimannil et al. found a significant increase in depressive symptoms among women with gestational diabetes.55 Approximately 20–25% of diabetic patients are affected by depression, which is double that in the general population.56 The cause behind the relation between diabetes and depression is not clear. The effect of hyperglycemia on the thyroid and stress axis, the metabolic impact of diabetes on the brain, and the psy-
chological burden of handling a chronic disease during pregnancy and the post-partum period have been postulated.57 This study found an inverse association between women’s age and post-partum depression with an increased risk of PPD with younger age. Some studies have found that a younger age is significantly related to increased EPDS scores.58,59 Teenage mothers encounter difficulty during the post-partum period due to their inability to cope with financial and emotional difficulties, as well as the challenge of motherhood.59 However, Cantilino et al. found no difference between depressed and non-depressed Brazilian mothers with regard to age.60 Cultural factors and social perspectives of young mothers in different countries could be a reason for this difference.61 The results of the present study further provide strong evidence of the importance of low income affecting mental health and are consistent with the findings from other developing countries, such as Vietnam and Pakistan, in which low-income mothers were at increased risk of developing PPD.62,63 Song et al. and Goyal et al. found that women with low socioeconomic status with insufficient health insurance and reduced access to health care in combination with low spouse, social and emotional support experience disadvantages that may lead to stress and thus need extra resources in order to cope.64,65 In this study, none of the hormone-related variables demonstrated a statistically significant association with post-partum depression, although some studies proposed that biological factors, such as hormones and neurotransmitters, play significant roles in the onset of post-partum depression.66 A hormonal cause for PPD has not been supported consistently by the literature;21,67 however, a genetic basis has been postulated.68 Traditional health beliefs and behaviors did not play a significant role in prevention of post-partum depression among Iranian women in this study and in some cases it was perceived as a double-edged sword, which could increase the risk of post-partum depression.69 More research is needed in this area. To the best of our knowledge, this is the first study that longitudinally examined the incidence of PPD during the periods 0–2, >2–8, and >8–12 weeks postpartum among women recruited from primary health centers in the developing world and in Iran. We also determined risk factors of PPD. The large sample size and validated screening instruments together with prospective data collection provided information on the
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incidence of PPD and its risk factors. It is incidence data that provide valid causal inference for the risk of developing a disease. In particular, the combination of risk factors, especially that of ritual practices, was studied for the first time in an Iranian population. Findings of the current study indicate that a history of mental disorders, such as anxiety during pregnancy, may serve as ‘flags’ in identification of post-partum depressive women. Staying in touch with mothers frequently during pregnancy and the post-partum period provides an opportunity for health service professionals to evaluate the mother’s emotional health and to screen for PPD risk factors to identify those at risk and intervene in a timely manner. Providing mothers with relevant information by health-care providers about mood changes during pregnancy and reducing or modifying risk factors could be an effective approach to reducing risk of developing PPD. While some risk factors, such as income, are not easy to change, other factors, such as social support and preventing unwanted pregnancy, can be avoided by family planning and education programs for mothers. With these measures, mothers can be empowered with coping strategies in adjusting to the challenges of motherhood. It should be stressed that although numerous studies have been carried out on PPD, further investigation needs to be conducted on the global prevalence and incidence of depressive symptoms in pregnant women and related risk factors, especially in other populations.
Acknowledgments We thank the health-care providers in primary health prenatal care centers and the pregnant women who participated in this study.
Disclosure None declared.
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instrument: The calendar of premenstrual experiences. Obstet Gynecol 1990; 76: 302–307. Vaux A, Phillips J, Holly L, Thomson B, Williams D, Stewart D. The social support appraisals (SS-A) scale: Studies of reliability and validity. Am J Community Psychol 1986; 14: 195–218. Vaux A. Factor structure of the Network Orientation Scale. J Psychol Rep 1985; 57: 1181–1182. Goldberg D. The Detection of Psychiatric Illness by Questionnaire. London: Oxford University Press, 1972. Olson DH, Fournier DG, Druckman JM et al. ENRICH: Enriching and Nurturing Relationship Issues, Communication and Happiness. Family Inventories Family Social Sciences. St Paul: University of Minnesota, 1985. Holmes TH, Rahe RH. The Social Readjustment Rating Scale. J Psychosom Res 1967; 11: 213–218. Reece SMC. The parent expectations survey. Clin Nurs Res 1992; 1: 336–346. Aghajani DM, Nasiri AF, Hosseini H. Effect of Vitagnose in treatment of premenstrual syndrome. J Herbal Med 2002; 2: 16–20. (In Persian.) Javaheri R. Effect of psychosocial factors on diabetes type-1 (Dissertation). Tehran: Institute of Psychology, 1989. (In Persian.) Yaghobi N, Nasresfehanian M, Shahmohamadi D. Study of mental health in Somesara. Gilan, J Think Behav 1995; 1: 55–65. (In Persian.) Tirgari A. Relationship between Emotional Intelligence and Marital Satisfaction. Tehran: Iran University of Medical Sciences, 2004. (In Persian.) Brahani MT. Assessment of Stress Risk Factors and Their Relationship with General Health in Tehran Hospital Staff. National Symposium of Stress; 1995. Iran: Tehran Psychological Institute, 1995. (In Persian.) Rychnovsky JD, Brady MA. Choosing a postpartum depression screening instrument for your pediatric practice. J Pediatr Health Care 2008; 22: 64–67. Beck CT, Gable RK. Comparative analysis of the performance of the postpartum depression screening scale with two other depression instruments. Nurs Res 2001; 50: 242–250. Kessler RC. The Epidemiology of Depression Among Women. In: Keyes C, Goodman S (eds). Women and Depression: A Handbook for the Social, Behavioral, and Biomedical Sciences. New York: Cambridge University Press, 2006; 22– 37. Gaynes BN, Gavin N, Meltzer-Brody S et al. Perinatal depression: Prevalence, screening accuracy, and screening outcomes. Evid Rep Technol Assess 2005; 119: 1–88. Evans J, Heron J, Francomb H, Oke S, Golding J. Cohort study of depressed mood during pregnancy and after childbirth. BMJ 2001; 323: 257–260. Escribà-Agüir V, Artazcoz L. Gender differences in postpartum depression: A longitudinal cohort study. J Epidemiol Community Health 2011; 65: 320–326. Nielsen D, Videbech P, Hedegaard M, Dalby J, Secher NJ. Postpartum depression: Identification of women at risk. BJOG 2000; 107: 1210–1217. Watanabe M, Wada K, Sakata Y et al. Maternity blues as predictor of postpartum depression: A prospective cohort study among Japanese women. J Psychosom Obstet Gynecol 2008; 29: 211–217.
43. Kirpinar I˙, Gözüm S, Pasinliog˘lu T. Prospective study of postpartum depression in eastern Turkey prevalence, sociodemographic and obstetric correlates, prenatal anxiety and early awareness. J Clin Nurs 2009; 19: 422–431. 44. Birkeland R, Thompson JK, Phares V. Adolescent motherhood and postpartum depression. J Clin Child Adolesc Psychol 2005; 34: 292–300. 45. Leung S, Arthur DG, Martinson I. Stress in women with postpartum depression: A phenomenological study. J Adv Nurs 2005; 51: 353–360. 46. Rayan DML, Misri N. Depression during pregnancy. Can Fam Physician 2005; 51: 1087–1093. 47. Huang YC, Mathers N. Postnatal depression–biological or cultural? A comparative study of postnatal women in the UK and Taiwan. J Adv Nurs 2001; 33: 279–287. 48. Gonidakis F, Rabavilas AD, Varsou E, Kreatsas G, Christodoulou GN. A 6-month study of postpartum depression and related factors in Athens Greece. Compr Psychiatry 2008; 49: 275–282. 49. Mohammad KI, Gamble J, Creedy DK. Prevalence and factors associated with the development of antenatal and postnatal depression among Jordanian women. Midwifery 2011; 27: e238–e245. 50. Cheng D, Schwarz EB, Douglas E, Horon I. Unintended pregnancy and associated maternal preconception, prenatal and postpartum behaviors. Contraception 2009; 79: 194–198. 51. Karaçam Z, Önel K, Gerçek E. Effects of unplanned pregnancy on maternal health in Turkey. Midwifery 2011; 27: 288– 293. 52. Goto A, Yasumura S, Reich MR, Fukao A. Factors associated with unintended pregnancy in Yamagata, Japan. Soc Sci Med 2002; 54: 1065–1079. 53. Abdollahy F, Mohammadpoor R. Adverse outcomes of unwanted pregnancy in the women referred to delivery room in Mazandran Educational Hospital 1999–2000. Mazandran Univ Med Sci J 2004; 14: 79–83. (In Persian.) 54. Hullfish KL, Fenner DE, Sorser SA, Visger J, Clayton A, Steers WD. Postpartum depression, urge urinary incontinence, and overactive bladder syndrome: Is there an association? Int Urogynecol J 2007; 18: 1121–1126. 55. Kozhimannil KB, Pereira MA, Harlow BL. Association between diabetes and perinatal depression among lowincome mothers. JAMA 2009; 301: 842–847. 56. Anderson RJ, Freedland KE, Clouse RE, Lustman PJ. The prevalence of comorbid depression in adults with diabetes: a meta-analysis. Diabetes Care 2001; 24: 1069–1078. 57. Dennis CLE, Janssen PA, Singer J. Identifying women at risk for postpartum depression in the immediate postpartum period. Acta Psychiatr Scand 2004; 110: 338–346. 58. Chaudron LH, Klein MH, Remington P, Palta M, Allen C, Essex MJ. Predictors, prodromes and incidence of postpartum depression. J Psychosom Obstet Gynecol 2001; 22: 103–112. 59. Sierra J. Risk Factors Related to Postpartum Depression in LowIncome Latina Mothers. Ann Arbor: ProQuest Information and Learning Company, 2008. 60. Cantilino A, Zambaldi CF, Albuquerque T, Paes JA, Montenegro ACP, Sougey EB. Postpartum depression in Recife–Brazil: Prevalence and association with bio-sociodemographic factors. J Bras Psiquiatr 2010; 59: 1–9. 61. McCoy SJB, Beal JM, Shipman SBM, Payton ME, Watson GH. Risk factors for postpartum depression: A retrospective
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symptoms in first-time mothers? Womens Health Issues 2010; 20: 96–104. Wissart J, Parshad O, Kulkarni S. Prevalence of pre- and postpartum depression in Jamaican women. BMC Pregnancy Childbirth 2005; 5: 15. Klier CM, Muzik M, Dervic K et al. The role of estrogen and progesterone in depression after birth. J Psychiatr Res 2007; 41: 273–279. Mancini F, Carlson C, Albers L. Use of the Postpartum Depression Screening Scale in a collaborative obstetric practice. J Midwifery Womens Health 2007; 52: 429–434. Klainin P, Arthur DG. Postpartum depression in Asian cultures: A literature review. Int J Nurs Stud 2009; 46: 1355– 1373.
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doi:10.1111/jog.12471
J. Obstet. Gynaecol. Res. Vol. 40, No. 12: 2191–2200, December 2014
Predictors and incidence of post-partum depression: A longitudinal cohort study Fatemeh Abdollahi1, Mehran Zarghami2,3, Md Zain Azhar4, Shariff-Ghazali Sazlina5 and Munn-Sann Lye6 1
Public Health Department, Faculty of Health, 2Psychiatry and Behavioral Sciences Research Center, Addiction Institute, and Department of Psychiatry, Mazandaran University of Medical Sciences, Sari, Iran; 4Department of Psychiatry, 5Department of Family Medicine, and 6Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia 3
Abstract Aim: This study was designed to identify the incidence and the related factors contributing to post-partum depression (PPD) in women in Iran for the first time. Material and Methods: A total of 2279 eligible pregnant women from 32–42 weeks of pregnancy to 12 weeks post-partum (2009) who attended primary health centers in Mazandaran province were screened for depression using the Iranian version of the Edinburgh Postnatal Depression Scale. Pregnant women free from depression were assessed using validated questionnaires, including the Premenstrual Syndrome Questionnaire, Social Support Appraisal Scale, Network Orientation Scale, General Health Questionnaire, Marital Inventory, Life Events Rating Scale and Parental Expectation Survey. Logistic regression analysis was used to determine the risk factors of PPD. Results: Of 1801 women who screened negative for depression at 32–42 weeks’ gestation, cumulative incidence proportions were 6.7%, 4.3% and 4.5% during 0–2, >2–8 and >8–12 weeks post-partum, respectively. The factors predictive of PPD were: history of depression during the first two trimesters of pregnancy (odds ratio [OR] = 2.55, 95% confidence interval [CI] = 1.59–4.1); psychiatric disorder during pregnancy (OR = 1.08, 95%CI = 1.06–1.11); gestational diabetes (OR = 2.93, 95%CI = 1.46–5.88); recurrent urinary infection (OR = 2.25, 95%CI = 1.44–3.52); unwanted pregnancy (OR = 2.5, 95%CI = 1.69–3.7) and low household income (OR = 3.57, 95%CI = 1.49–8.5). The risk was decreased with increasing age (OR = 0.88, 95%CI = 0.84–0.92) and those with high self-efficacy for mothering (OR = 0.7, 95%CI = 0.62–0.78). Conclusion: A high rate of new cases of PPD was identified in Iranian women. A combination of psychological, sociological, obstetric and sociodemographic factors can render mothers vulnerable to post-partum depression. Key words: depression, incidence, reproductive health, risk factors.
Introduction The World Health Organization has estimated that by 2020, major depressive disorder (MDD) would constitute the second largest component of the burden of disease worldwide.1 One of the subtypes of MDD rec-
ognized by the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV-TR) is post-partum depression (PPD).2 Globally, the prevalence of PPD can be as high as 60% in some countries,3 while in Iran it varies between 20.3% and 35%.4–7 The limited number of available studies on the incidence of PPD reported
Received: October 12 2013. Accepted: April 13 2014. Reprint request to: Professor Munn-Sann Lye, Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Malaysia. Email: [email protected]
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that 6.5% of mothers develop a new episode of depression during the first 3 months after birth.8 There is a three-fold increase in the risk of depression during 3–6 months following birth compared to other times of life.9 PPD affects all aspects of a woman’s life, including her relationship with her partner and her child’s development.9–11 It also affects a woman’s mental health in the long term,12 and negatively affects all areas of quality of life from physical to social functioning.13 Disorders in cognitive, emotional and social development are more common in children of mothers with PPD.14–16 Conclusions from studies on the cause of PPD have been inconsistent.8,17,18 Numerous causes have been suggested; however, no single hypothesis is able to elucidate this phenomenon.8,19 Cultural aspects also play a fundamental role in the way motherhood is perceived and experienced in different cultures.20,21 Most of the rigorous studies on PPD so far have been conducted in Western countries and reliable data are relatively lacking for Asian populations.20,21 Also, not many studies captured incidence data, which have inherently greater validity in supporting causal inference for the risk of developing PPD. This study was carried out to determine demographic, sociological, psychological, cultural, obstetric, gynecological and possible hormone-related factors that are involved in the development of post-partum depression in a longitudinal follow-up study in the Iranian population for the first time.
Methods In this cohort follow-up study, 2279 pregnant women, literate in Persian, at the gestational stage of 32–42 weeks, who attended prenatal care at urban and rural primary health centers (PHC) of Mazandaran University of Medical Sciences (MAZUMS) in Mazandran Province in northern Iran from January to June 2009 were recruited. Women who were depressed during 32–42 weeks of pregnancy according to the Edinburgh Postnatal Depression Scale (EPDS)22 or who were on pharmacological treatment for psychiatric problems were excluded. Mothers who were found to have depression based on the EPDS and who were in need of specialized assistance regarding prevention or early treatment were referred to a physician for treatment. The potential risk factors (indicators) before and during pregnancy and at delivery were utilized in estimating the risk of PPD over 12 weeks post-partum. Cumula-
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tive incidence proportions were computed for the periods 0–2, >2–8 and >8–12 weeks post-partum. Written consent was obtained from women with the assurance of confidentiality of information given. The study was approved by the Faculty of Medicine and Health Sciences Medical Research Ethics Committee, University Putra Malaysia and Ethics Committee of Mazandaran University of Medical Sciences in Iran. Validated instruments that were used in this study included the Premenstrual Syndrome Questionnaire (PMSQ),23 Social Support Appraisals Scale (SSA),24 Network Orientation Scale (NOS),25 General Health Questionnaire (GHQ-28),26 Marital Inventory (ENRICH),27 Life Events Rating Scale (LERS),28 Parental Expectation Survey (PES)29 and EPDS.22 Standard questionnaires were used for other information. Demographic characteristics included mother’s age, marital age, marital status, parity, maternal education, mother’s and father’s employment and total household income. Information on mental health included previous PPD, family history of depression, depression during first and second trimester of pregnancy and anxiety during pregnancy. Hormone-related conditions included irritable moods before menstruation, mood instability secondary to oral contraception and mood instability at puberty period. Psychosocial data included life events, social support, marital relationship, parental selfefficacy and abuse. Obstetric and gynecological data included pregnancy wantedness, mode of delivery, sex of baby, history of abortion or stillbirth, the gestational age at first antenatal care, the number of antenatal care visits, place of delivery and any complication during pregnancy. Rituals and customs after childbirth included information on behavior, such as having 42 days of rest after childbirth, giving a party and eating traditional food. PMSQ,30 SSA,31 GHQ,32 ENRICH,33 LERS34 and EPDS5 have been used before in the Iranian population, and their validity in the Persian language have been established. Questionnaires for sociodemographic information that have not been used before in Iran were translated into Persian, and back-translated for verification. The internal consistency of the PES and NOS as measured by Cronbach’s alpha was 0.59 and 0.91, respectively. The content validity of all questionnaires was tested by 10 experts in the Psychiatry and Behavioral Sciences Research Center of Mazandaran University of Medical Sciences. All questionnaires were used after pretesting with a sample of 60 healthy unselected pregnant women in PHC (Cronbach’s alpha ranged between 0.42 and 0.92).
© 2014 The Authors Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology
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The EPDS is the most widely used screening tool to detect mothers who are suffering from PPD.35 We used the Iranian version of EPDS, which consists of 10 items relating to mood. Each item is scored from 0 to 3 with four responses (‘no, not at all, quite often, yes’) on the severity of symptoms during the past week. The total score was calculated by computing the scores for each of 10 items with seven (items 3, 5, 6, 7, 8, 9, 10) of the 10 items being scored reversely.35,36 Studies in Iran showed a score of greater than 12 was a valid cut-off value for the provisional diagnosis of PPD with 95% sensitivity and 93% specificity.4,5 A higher score for PES and MI indicates better parental self-efficacy and marital relationship, while a lower score for GHQ, PMSQ, SSA, NOS and LERS indicates better health status, social support as well as fewer adverse life events. The women were categorized in two groups. One category included mothers who obtained scores above the EPDS threshold level of 12 at each follow-up time period: 0–2, >2–8, and >8–12 weeks post-partum. The other category, a reference category, included mothers who received scores less than the cut-off point. Simple logistic regression was used to determine the putative effect of each potential risk factor on PPD. Variables that were statistically significant in the univariate analysis were then examined in a hierarchical multiple logistic regression. Based on literature review and theory of post-partum depression, variables were entered into the model in the following sequential order to obtain adjusted odds ratios: mental health, psychosocial, obstetric and gynecological, sociodemographic, and hormone-related factors.
Results During the study period, 2626 women were eligible for the study and 2359 (89.9%) volunteered to participate. Of those, 2279 (96.6%) completed the EPDS and other questionnaires. A total of 478 (21%) women whose EPDS scores were more than the threshold of 12 during the third trimester or who were on medication for psychiatric disorders were excluded from the study. The remaining 1801 (79%) mothers were followed up to ascertain incident cases of PPD during the periods 0–2, >2–8 and >8–12 weeks post-partum. Response rates during 0–2, >2–8 and >8–12 weeks post-partum were 96.6% (1739/1801), 93.3% (1622/1739) and 94.4% (1531/1622), respectively. Overall, 254 (14.10 %) mothers were found to have EPDS greater than 12 over
this 12-week period and were compared with mothers who were not depressed (1292) over the same 12-week period. A comparison was made between pregnant women who participated in the study but did not complete the study (255; 14.15%) and the women who completed the study (1546; 85.84%) and found no significant difference in terms of the average age, women’s and their husbands’ education, experience of depression, anxiety during pregnancy and previous post-partum depression as well as the mean EPDS scores during the third trimester. The mean age and age at marriage of these women were 25.9 ± 5.2 years and 20.4 ± 4 years, respectively. More than 60% of women were primigravidae and half of them and their husbands’ education were less than high school (50.5% and 41.3%, respectively). About half of them (50.6%) were recruited from rural PHC. The majority of women (60.1%) had fewer than nine prenatal visits (mean = 9.3 ± 3.6). About half of the babies (53.9%) were born vaginally. Approximately 42 (2%) mothers stated having PPD in previous pregnancies. Two hundred fifty-two mothers (14%) described having irritable mood prior to menstruation. A total of 178 (9.9%) had a history of depression in the first and second trimesters, while 780 (43.3%) experienced anxiety. The mean scores of social support and social isolation based on SSA, NOS, MS, PSE and mean number of LE were 47.24 ± 4.91, 47.81 ± 4.36, 25.05 ± 3.61, 7.96 ± 1.49 and 2.81 ± 2.73. About 12.21% of the women reported at least one kind of abuse. The number of cultural practices ranged from zero to 27 with a mean of 14.13 ± 3.9. The incidence proportions of depression occurring in the post-partum periods of 0–2, >2–8 and >8–12 weeks post-partum were 6.9% (120/1739), 4.6% (69/ 1509), and 4.8% (65/1357), respectively. PPD incidence during the study at each period of data collection is shown in Figure 1. Tables 1 and 2 describe the frequency and percentage for post-partum depression by each category of the significant variables, univariate odds ratio (OR) with 95% confidence interval (CI), and P-values, based on EPDS score. A total of 1449 mothers were available for analysis. Hierarchical multiple logistic regression showed that there was increased odds of PPD with lower state of general health (OR = 1.08 [95%CI: 1.06–1.11]), being depressed during first and second trimester of
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Participating mothers from 32 weeks’ pregnancy to term, 2359
Total number of mothers who completed first EPDS questionnaire 2279, 80 (3.4%) missing
1801 (71%) mothers’ EPDS ≤ 12 from 32 weeks’ pregnancy to term
2 weeks after birth, 1739 followed up, 62 (3.4%) dropouts
120
1619
8 weeks after birth, 1622 followed up, 117 (6.7%) dropouts
Dropouts 1440
69
Dropouts
51
110
Dropouts
62
7
Dropouts Dropouts
1292
65
83
30
36
3
34
13
4
26
Dropouts
35
1
12 weeks after birth, 1531 followed up, 91 (5.6%) dropouts Figure 1 Incidence of post-partum depression in 1801 women who had Edinburgh Postnatal Depression Scale (EPDS) ≤ 12 from 32 weeks’ gestation to term and followed until 12 weeks post-partum. ( ) EPDS > 12. (□) EPDS ≤ 12.
pregnancy (OR = 2.55 [95%CI: 1.59–4.1]), experienced recurrent urinary infection (OR = 2.25 [95%CI: 1.44– 3.52]), unwanted pregnancy (OR = 2.5, [95%CI: 1.69– 3.7]), gestational diabetes (OR = 2.93 [95%CI =
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1.46–5.88]) and household income (OR = 3.57 [95%CI: 1.49–8.5]). The odds of PPD decreased with sufficient parenting skills (OR = 0.7, [95%CI: 0.62–0.78]) and among older mothers (OR = 0.88 [95%CI: 0.84–0.92]).
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Table 1 Sociodemographic and obstetric and gynecological factors associated with depression over 12 weeks post-partum using simple logistic regression (n = 1546) Risk factors
B
B(SE)
Odds ratio
95%CI
P-value
Age (years) Age at marriage (years) Education (years) Total household income (tomans, monthly) Low (less than 350 000)† Medium (350 000–450 000) High (more than 450 000) Gravida Family structure Extend Nuclear Occupation Housewife Employed Anemia Yes No Gestational diabetes Yes No Recurrent urinary infection Yes No Reason for sick leave Pregnancy related Miscellaneous Planned pregnancy Not planned Planned Unknown neonatal complications Yes No Infection Yes No
−0.06 −0.03 −0.04
0.01 0.01 0.02
0.94 0.96 0.95
0.91–0.96 0.93–0.99 0.91–0.99
0.001 0.04 0.02 0.002
0.78 0.44
0.25 0.28
1.32–3.6 0.89–2.73
−0.24
0.09
2.18 1.56 1 0.78
0.56–0.93
0.006
0.3
0.14
1.35 1
1.01–1.8
0.04
1.24
0.46
3.46 1
1.39–8.62
0.008
0.44
0.21
1.55 1
1.03–2.35
0.03
0.78
0.28
2.19 1
1.26–3.8
0.005
0.71
0.19
2.04 1
1.41–2.96
0.001
−1.33
0.59
0.26 1
0.08–0.85
0.02
0.4
0.16
1.5 1
1.09–2.06
0.01
0.66
0.33
1.94
1.01–3.72
0.04
0.75
0.31
2.13 1
1.15–3.94
0.01
†Toman: 10 rials = 1 Toman = 0.01 USD. CI, confidence interval.
Table 3 shows B coefficient estimates and the corresponding OR indicating the independent effect of each variable controlling for the effect of other variables in the model.
Discussion Prevalence and incident measurements are important for identifying health problems and disease burden.37 Although the incidence rate is a unique and significant finding from both academic and clinical perspectives, few studies have actually investigated it. What makes
comparison with other studies difficult is the variation in the timing of post-partum follow-up. Gaynes et al. reported that about 6.5% of women developed a new episode during the first month post-partum,38 which is consistent with our findings. In this study, there was a slight decrease in PPD incidence from 6.9% for weeks 0–2 to 4.8% for weeks >8–12 post-partum. In longitudinal studies, the EPDS with the same cut-off value was used by Evens et al. in the UK and by Escriba-Aguir et al. in Spain.39,40 They reported a decrease in the incidence rates over the first post-partum year from 5.31% and 9.3% to 2.61% and 4.4%, respectively.39,40
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Table 2 Psychological and psychosocial factors associated with depression over 12 weeks post-partum using simple logistic regression (n = 1546) Risk factors Depression in 1st/2nd trimesters of pregnancy Yes No Anxiety in pregnancy Yes No Family history of depression Yes No General health status Not healthy (>21) Healthy (≤21) Social support during pregnancy Low (≥51) Medium (45–50) High (≤44) Social isolation during pregnancy Low (≥51) Medium (45–50) High (≤44) Number of life events ≥4 2–3 ≤1 Postnatal parenting self-efficacy Low (≤7) Medium (7.01–8.91) High (≥9)
B
B(SE)
Odds ratio
95%CI
P-value
0.71
0.19
2.04 1
1.39–3.01
0.001
0.5
0.13
1.65 1
1.26–2.17
0.001
0.58
0.24
1.79 1
1.1–2.91
0.01
0.7
0.13
2.02 1
1.54–2.65
0.001
0.45 0.2
0.19 0.17
1.58 1.22 1
1.08–2.3 0.87–1.71
0.01 0.23
0.42 0.13
0.18 0.17
1.53 1.13 1
1.06–2.19 0.81–1.58
0.02 0.44
0.4 0.11
0.16 0.17
1.49 1.12 1
1.08–2.05 0.8–1.58
0.01 0.49
0.67 0.004
0.18 0.17
1.96 1.004 1
1.36–2.84 0.71–1.41
0.001 0.98
CI, confidence interval.
Table 3 Risk of post-partum depression over 12 weeks post-partum using hierarchical multiple logistic regression (n = 1449) Risk factors
Adjusted odds ratio
95%CI
P-value
General health status Depression in 1st/2nd trimester Postnatal parenting self-efficacy Unwanted pregnancy Recurrent urinary infection Gestational diabetes Mother’s age Household income: Low vs high Medium vs high
1.08 2.55 0.7 2.5 2.25 2.93 0.88
1.06–1.11 1.59–4.1 0.62–0.78 1.69–3.7 1.44–3.52 1.46–5.88 0.84–0.92
0.001 0.001 0.001 0.001 0.001 0.002 0.001
3.57 1.72
1.49–8.5 0.66–4.48
0.004 0.26
CI, confidence interval.
Two strong predictors of post-partum depression in this study were psychological distress (using GHQ) during 32–42 weeks of gestation, and depression in the first and second trimesters of pregnancy. These find-
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ings were consistent with a longitudinal study among 5262 Danish women by Nielson et al. who found a similar association between GHQ scores during late pregnancy and PPD at the fourth month post-partum.41
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Other studies also showed that women with PPD were most likely to have psychological symptoms during pregnancy.42,43 Three meta-analyses and additional studies regarding risk factors for PPD on 24 000 subjects concluded that having depression and anxiety during pregnancy and previous history of psychiatric illness are strong risk factors for developing PPD.11 This study also found that a lack of postnatal parental competence and low parenting self-efficacy were significant risk factors for PPD. Several studies have demonstrated that the stresses of child care play significant roles in PPD.7,11,44,45 Women who have a positive view of their maternal capabilities were found to be more able to care for the infant with confidence immediately after birth.46 Huang and Mathers reported that Taiwanese mothers who had problems in adapting to the role of motherhood had higher scores on EPDS.47 It is possible that these mothers experienced more stress when they began to care for the baby or were not being prepared for motherhood during their pregnancy.48,49 A woman’s mental health could be challenged by unwanted pregnancy and post-partum complications. This study and other studies concluded that the PPD is more prevalent among mothers with unwanted pregnancies.50,51 Unwanted pregnancy can cause adverse physical, psychological and social consequences in the short- and long-term for the women52,53 and affect the mothers’ feelings towards their fetus, as well as towards others involved.11 Few studies have looked specifically at the association between recurrent urinary infection in pregnancy and post-partum depression. In this study, women with urinary tract infection during pregnancy had increased risk of PPD (OR = 2.25; 95%CI = 1.44–3.52). This finding is also supported by Hullfish et al.,54 but it is not clear how urgency and urinary incontinence could have increased the risk of PPD. Perhaps women who have these problems may be too embarrassed to talk about them, further heightening stress levels contributing to PPD. Women with gestational diabetes in this study had almost threefold the odds of PPD compared with women who did not. Consistent with this study, Kozhimannil et al. found a significant increase in depressive symptoms among women with gestational diabetes.55 Approximately 20–25% of diabetic patients are affected by depression, which is double that in the general population.56 The cause behind the relation between diabetes and depression is not clear. The effect of hyperglycemia on the thyroid and stress axis, the metabolic impact of diabetes on the brain, and the psy-
chological burden of handling a chronic disease during pregnancy and the post-partum period have been postulated.57 This study found an inverse association between women’s age and post-partum depression with an increased risk of PPD with younger age. Some studies have found that a younger age is significantly related to increased EPDS scores.58,59 Teenage mothers encounter difficulty during the post-partum period due to their inability to cope with financial and emotional difficulties, as well as the challenge of motherhood.59 However, Cantilino et al. found no difference between depressed and non-depressed Brazilian mothers with regard to age.60 Cultural factors and social perspectives of young mothers in different countries could be a reason for this difference.61 The results of the present study further provide strong evidence of the importance of low income affecting mental health and are consistent with the findings from other developing countries, such as Vietnam and Pakistan, in which low-income mothers were at increased risk of developing PPD.62,63 Song et al. and Goyal et al. found that women with low socioeconomic status with insufficient health insurance and reduced access to health care in combination with low spouse, social and emotional support experience disadvantages that may lead to stress and thus need extra resources in order to cope.64,65 In this study, none of the hormone-related variables demonstrated a statistically significant association with post-partum depression, although some studies proposed that biological factors, such as hormones and neurotransmitters, play significant roles in the onset of post-partum depression.66 A hormonal cause for PPD has not been supported consistently by the literature;21,67 however, a genetic basis has been postulated.68 Traditional health beliefs and behaviors did not play a significant role in prevention of post-partum depression among Iranian women in this study and in some cases it was perceived as a double-edged sword, which could increase the risk of post-partum depression.69 More research is needed in this area. To the best of our knowledge, this is the first study that longitudinally examined the incidence of PPD during the periods 0–2, >2–8, and >8–12 weeks postpartum among women recruited from primary health centers in the developing world and in Iran. We also determined risk factors of PPD. The large sample size and validated screening instruments together with prospective data collection provided information on the
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incidence of PPD and its risk factors. It is incidence data that provide valid causal inference for the risk of developing a disease. In particular, the combination of risk factors, especially that of ritual practices, was studied for the first time in an Iranian population. Findings of the current study indicate that a history of mental disorders, such as anxiety during pregnancy, may serve as ‘flags’ in identification of post-partum depressive women. Staying in touch with mothers frequently during pregnancy and the post-partum period provides an opportunity for health service professionals to evaluate the mother’s emotional health and to screen for PPD risk factors to identify those at risk and intervene in a timely manner. Providing mothers with relevant information by health-care providers about mood changes during pregnancy and reducing or modifying risk factors could be an effective approach to reducing risk of developing PPD. While some risk factors, such as income, are not easy to change, other factors, such as social support and preventing unwanted pregnancy, can be avoided by family planning and education programs for mothers. With these measures, mothers can be empowered with coping strategies in adjusting to the challenges of motherhood. It should be stressed that although numerous studies have been carried out on PPD, further investigation needs to be conducted on the global prevalence and incidence of depressive symptoms in pregnant women and related risk factors, especially in other populations.
Acknowledgments We thank the health-care providers in primary health prenatal care centers and the pregnant women who participated in this study.
Disclosure None declared.
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