JOURNAL OF WOMEN’S HEALTH Volume 25, Number 11, 2016 ª Mary Ann Liebert, Inc. DOI: 10.1089/jwh.2015.5310

Trajectories of Depressive Symptoms Throughout the Peri- and Postpartum Period: Results from the First Baby Study Jennifer S. McCall-Hosenfeld, MD, MSc,1,2 Kristen Phiri, MD,3 Eric Schaefer, MS,2 Junjia Zhu, PhD,2 and Kristen Kjerulff, PhD2,4

Abstract

Background: Postpartum depression (PPD) is a common complication of childbearing, but the course of PPD is not well understood. We analyze trajectories of depression and key risk factors associated with these trajectories in the peripartum and postpartum period. Methods: Women in The First Baby Study, a cohort of 3006 women pregnant with their first baby, completed telephone surveys measuring depression during the mother’s third trimester, and at 1, 6, and 12 months postpartum. Depression was assessed using the Edinburgh Postnatal Depression Scale. A semiparametric mixture model was used to estimate distinct group-based developmental trajectories of depression and determine whether trajectory group membership varied according to maternal characteristics. Results: A total of 2802 (93%) of mothers completed interviews through 12 months. The mixture model indicated six distinct depression trajectories. A history of anxiety or depression, unattached marital status, and inadequate social support were significantly associated with higher odds of belonging to trajectory groups with greater depression. Most of the depression trajectories were stable or slightly decreased over time, but one depression trajectory, encompassing 1.7% of the mothers, showed women who were nondepressed at the third trimester, but became depressed at 6 months postpartum and were increasingly depressed at 12 months after birth. Conclusions: This trajectory study indicates that women who are depressed during pregnancy tend to remain depressed during the first year postpartum or improve slightly, but an important minority of women become newly and increasingly depressed over the course of the first year after first childbirth. Keywords: depression, postpartum, women’s health, reproductive health, social support, marital status, trajectory analysis Introduction

ostpartum depression (PPD), affecting *13%–14% of women, is the most common complication of childbearing.1,2 Symptoms include excessive worrying, tearfulness, loss of appetite, feelings of inadequacy, insomnia, and depressed mood.3 To be classified as PPD, symptoms of major depression emerge within the peripartum period through 4 weeks postpartum, must be present for at least 2 weeks, and must interfere with the mother’s everyday functional living.4,5 This definition contrasts with the ‘‘baby blues,’’ which involves symptoms that appear and disappear within days after delivery, and postpartum psychosis, which is a rarer and much more extreme manifestation of depression.6,7 PPD may

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lead to long-term depressive illness in the new mother, as well as adversely affect the health and well-being of her partner and baby.8 Healthcare providers must be cognizant of the patterns of depression that can occur in the peripartum and postpartum time frame. In a recent meta-analysis of 23 longitudinal studies of PPD, the majority of studies showed that the severity of depression decreased over time,8 a finding consistent with the literature.9 Despite the evidence that the severity of depressive symptoms tends to decrease, patterns of depression are not homogenous among peripartum and postpartum women. Among depressed women, numerous studies have identified unique groups such as women with chronic major depression, women with chronic minor depression, and

Departments of 1Medicine and 2Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania. 3 Williamsport Family Medicine Residency Program, Williamsport, Pennsylvania. 4 Department of Obstetrics and Gynecology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.

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DEPRESSION TRAJECTORIES PERI- AND POSTPARTUM

women who have recurrent or episodic depression.8 The risk factors that predict the onset and timing of depression among these women are heterogeneous. The course of PPD can be heterogeneous as well, with some women experiencing resolution of symptoms, whereas others develop ongoing, increasingly severe, or episodic symptoms. Thus, researchers have called for studies that examine the role of known risk factors in studies of PPD.8 Numerous risk factors for developing PPD have been described in the literature. Prominent among these include a history of depression or anxiety, unstable or dissatisfied marital or relationship status, and inadequate social support.10 Additional risk factors that have been shown to impact the development of PPD include younger age,11,12 race/ethnicity,8,13 prepregnancy body mass index (BMI),14,15 lower educational status,11 lower socioeconomic status (SES),16 and health insurance status.17 The purpose of this study was to examine the role these various risk factors play in the trajectory of PPD. Numerous studies have shown a history of depression or anxiety to be a risk factor for PPD.10,16,18–20 In 2013, Raisanen et al. reported that after adjustment for confounding variables, antenatal depression history was the strongest risk factor for PPD.19 Moreover, among Chinese women both antenatal depression and anxiety-prone personality were independent predictors of postnatal depression.10 However, in a 2014 literature review, Vliegen et al. found that many longitudinal studies of PPD did not investigate history of maternal depression, and called for future research to examine prepregnancy maternal mental health in greater detail.8 Marital status is also a key factor in the development of PPD. Risk for postnatal depression has been shown among women living without a partner and among women having a poorer quality of relationship with their present or recent partner.21 Higher postnatal depression scores were found among women who were single, separated, or noncohabiting than those who were married.22 Another key risk factor that contributes to the development of PPD is lack of social support. Social support from friends and relatives and partner support from the father of the baby are important and much anticipated sources of help for the new mother.23,24 During times of stress, support such as advice, help with chores and tasks, and emotional support has been shown to be a protective factor against the development of PPD,25 whereas women reporting little or no social support have an increased risk for developing PPD.2,16,21,26–31 In addition, although 11.5%–50% of women experiencing PPD report onset of depression before or during their pregnancy,32,33 few studies have examined whether women experiencing PPD have had a history of anxiety or depression, and whether depression is present during the peripartum period in addition to postpartum.8 Thus, in this study, we examine longitudinal patterns, or trajectories, of depression during the third trimester of pregnancy. We define our time frame to include data collected in the third trimester, before delivery, through a 1-year follow-up during the postpartum period. We further examine the association of risk factors in the development of those depression trajectories. Thus, one of the primary aims of this study is to examine PPD trajectories while including a peripartum time point, addressing a criticism in the literature that PPD reflects a vulnerability that occurs before pregnancy or delivery.34

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Trajectory analysis has rarely been used in longitudinal studies of PPD,8 but has many benefits that commend its use for this study. Trajectory analysis can identify distinctive groups of individual trajectories within a large sample, estimate the shape of each trajectory, use these results to calculate the probability of membership in each trajectory, and determine the characteristics of individuals that make membership in each trajectory group likely.35 We hypothesize that women with a history of anxiety or depression, unmarried women, and women with lower social support are likely to have greater levels of depression than married women with more social support who do not have a history of anxiety or depression. Materials and Methods Subjects

Data were gathered from The First Baby Study,36 in which 3006 women in Pennsylvania who were pregnant with their first baby and planning to deliver in Pennsylvania were surveyed. The design of this study has been previously described.36 In brief, women were recruited from participating hospitals throughout the state of Pennsylvania. Recruitment methods were designed to enroll women of varying socioecomonic status. Recruitment methods included placement of study materials such as brochures and flyers in venues likely to serve pregnant women such as hospitals, obstetricians’ offices, and community health centers, as well as press releases, and direct recruitment at childbirth education classes. Enrollment criteria for women included nulliparity, either English or Spanish speaking, and ages 18–35 years at the time of enrollment. All participants agreed to be interviewed once before delivery during the third trimester, and several times postdelivery. Interviews were conducted by trained interviewers via telephone. This study examines data from the third trimester (baseline) and at 1, 6, and 12 months postpartum. The study was reviewed and approved by the Pennsylvania State University College of Medicine Institutional Review Board. Measures

The primary outcome variable was depressive symptoms as measured using the Edinburgh Postnatal Depression Scores (EPDSs).37 The EPDS is a symptom-based screening scale. It is the most widely used instrument for screening for postnatal depression, and has been validated against clinical criteria, such as the Diagnostic and Statistical Manuals III and IV, and across a number of different cultures, and found to have good sensitivity for detecting clinically significant PPD.38,39 The EDPS was administered at baseline during the third trimester of pregnancy, and at three time points postpartum: 1, 6, and 12 months. The EPDS is a validated 10-item self-report questionnaire designed to screen for postnatal depression. Based on several pilot studies that we conducted among postpartum women in Pennsylvania, we found one item that women found confusing. This item was ‘‘Things have been getting on top of me,’’ with response options of ‘‘Yes, most of the time I haven’t been able to cope at all,’’ Yes, sometimes I haven’t been coping as well as usual,’’ ‘‘No, most of the time I have coped quite well,’’ and ‘‘No, I have been coping as

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well as ever.’’ The phrase ‘‘Things have been getting on top of me’’ is not commonly used in U.S. vernacular. Therefore, we changed that item to ‘‘I have had trouble coping.’’ We also changed the last item ‘‘The thought of harming myself has occurred to me’’ to ‘‘The thought of harming myself or others has occurred to me.’’ We changed this last item to include harming others because there have been instances of women who harmed their children during the postpartum period, including events that have been attributed to PPD. Both of these modified items exhibited very good corrected item-total correlations and the overall Cronbach’s alpha was 0.81. Participants were instructed to answer each question based on how they had felt within the previous 7 days. Each answer was scored on a scale of 0–3, with a score of 3 indicating the most severe depressive symptoms; thus total scores could range from 0 to 30. Higher total scores indicated worse depressive symptoms. We used a cut-off of 12 or greater indicating probable depression, as recommended in a systematic review of studies validating the EPDS.40 Key predictor variables were hypothesized to impact the patterns of depression; these include history of anxiety or depression, marital status, and social support. These variables were selected based on their association with postnatal depression in the literature.10,16,18,23–31,41 A history of anxiety or depression was measured in the baseline survey, which was given during the mother’s third trimester. Patients were asked, ‘‘Before this pregnancy, had a doctor or other health care professional told you that you have any of the following health conditions.anxiety or depression?’’ This question has a high level of face validity, and was previously utilized in the Commonwealth Fund 1998 Survey of Women’s Health42 and the Central Pennsylvania Women’s Health Study (CePAWHS).43 Marital status was categorized as married, living with partner, not living with partner, and unattached. Participants were asked whether they had a partner or significant other, if they were married, and if they were currently living with their partner. These questions were used in CePAWHS.43 Social support was measured at baseline using five questions from the Medical Outcomes Study-Social Support Survey (MOS-SSS), encompassing emotional, informational, tangible, and affectionate support, and positive social interaction. Response items were chosen from the original 19-item scale to reduce respondent burden. Women were asked, ‘‘Please tell me how often each of the following kinds of support are available to you: someone to confide in or talk to about your problems, someone to get together with for relaxation, someone to help you with daily chores if you are sick, someone to turn to for suggestions about how to handle a personal problem, someone to love and make you feel wanted.’’44 Each question on the MOS-SSS is ranked on a scale of 1–5 (1 = felt support none of the time, 5 = felt support all of the time), equating to a total score ranging from 5 to 25. For oneway ANOVA, we used the following cut-offs to categorize women for social support: 0.7 and odds of correct classification should be >5 for all groups. We extended our six-group model by including maternal characteristics as risk factors for trajectory group membership. This extended model allowed us to examine how variables such as age, marital status, or social support affected the probability of belonging to each of the six distinct trajectory groups. Age and social support were treated as continuous variables in these models. The extension constituted a multinomial logit model, in which the log odds of group membership were modeled as a function of risk factors included in the model. In this extended model, we examined only those maternal characteristics related to our hypothesized primary predictors (a history of anxiety/depression, marital status, and social support) and those covariates that were associated with postpartum depressive symptoms in one-way ANOVA models: age, race, education, poverty status, and health insurance. Because prepregnancy BMI was not associated with depression at any time point, it was not included in the extended trajectory models. We imputed missing values for age (N = 6), marital status (N = 1), and social support (N = 3) at their median values for use in the extended model. To achieve convergence, the extended model that included all prespecified covariates required us to force three of the six groups to have linear trajectories, which was sensible because a quadratic trend did not yield a significant p value for these three groups. Due to the number of parameters in the model and the small number estimated to belong to some trajectory groups, we aimed to find a parsimonious model. From the model that included all prespecified covariates, age, race, poverty status, and health insurance were all highly nonsignificant ( p > 0.30) and were dropped from the model. Among the remaining four variables (history of anxiety and depression, marital status, social support, and education), we fit all possible subsets (16 models total) and selected the model with the lowest value of AIC. AIC favored a model that included only our three hypothesized primary predictor variables: history of anxiety and depression, social support score, and marital status. We specified a priori that the group with the lowest overall depression score would be the reference category, reasoning that the lowest overall depression was the most clinically relevant comparator. Thus, with trajectory group 1 as the reference group, odds ratios (ORs) and 95% confidence intervals (CIs) for each variable were reported. We also reported estimated probabilities of group membership from this model. Results

A total of 3006 mothers enrolled in the study. All mothers completed the EPDS in the baseline survey, 3005 (>99%) mothers completed EPDS in the 1-month survey, 2911 mothers (97%) completed the EPDS in the 6-month survey, and 2802 (93%) completed the EPDS in the 12-month survey.

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At baseline, 8.52% had EPDSs of 12 or higher. At 1 month postpartum, 5.06% had EPDSs of 12 or higher; at 6 months postpartum 4.92% had EPDSs of 12 or higher and at 12 months postpartum, 4.79% had EPDSs of 12 or higher. Overall, 16.00% of the women had an EPDS score at 12 or above at least once during the four measured time points. Table 1 shows the results of one-way ANOVA models used to test for differences in EPDS for each variable at each time point. Younger women (£20 years) had higher EPDSs, indicating greater depression at baseline (mean 7.5, SD 5.0), 6 months (mean 5.2, SD 4.9), and 12 months (mean 5.2, SD 4.8) than older women (>30 years) at baseline (mean 5.4, SD 3.5), 6 months (mean 4.2, SD 3.5), and 12 months (mean 4.3, SD 3.6). At these same time points, women who were not living with their partner or who were unattached also reported higher EPDSs than women who were attached or who were living with their partner. At all four time points, women with a social support scale score 15, similar to clinically depressed women in trajectory 6. Table 2 reports estimated ORs of trajectory group membership (with trajectory group 1, the least depressed group, as the reference group) for the model that adjusted for history of anxiety or depression, social support, and marital status. The model indicates that compared with women with no history of anxiety of depression, women with a history of anxiety or depression had 7.9 times higher odds of belonging to group 4 (95% CI 3.6–17.4), 10.8 times higher odds (95% CI 6.3–18.5) of belonging to group 5, and 18.5 times higher odds (95% CI 7.6–45.1) of belonging to group 6, all compared with group 1. Compared with married women, women who were unattached had 8.6 times higher odds (95% CI 2.5–29.6) of belonging to group 6 than to group 1; women who were not living with a partner had 2.9 times higher odds (95% CI 1.3– 6.6) of belonging to group 5 than to group 1, and women who were not partnered had 7.8 higher odds (95% CI 3.1–19.8) of belonging to group 4 than to group 1. As anticipated, higher social support scores were associated with lower odds of

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MCCALL-HOSENFELD ET AL.

Table 1. Summary of Baseline Variables and Their Association with Edinburgh Postnatal Depression Scores at Each Time Point EPDS, mean (SD) Overall (N = 3006), N (%) Age £20 21–25 26–30 >30 Race Nonwhite White Prepregnancy BMI Normal/underweight Overweight/obese Marital status Married Living with partner Not living with partner Unattached Education High school or less Some college or technical College graduate or higher Poverty status Poverty Near poverty Nonpoverty Insurance Public/self Private Social support score

Trajectories of Depressive Symptoms Throughout the Peri- and Postpartum Period: Results from the First Baby Study.

Postpartum depression (PPD) is a common complication of childbearing, but the course of PPD is not well understood. We analyze trajectories of depress...
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