Australian and New Zealand Journal of Obstetrics and Gynaecology 2015; 55: 156–162
DOI: 10.1111/ajo.12263
Original Article
Women’s beliefs about the duration of pregnancy and the earliest gestational age to safely give birth Lillian Y. ZHANG, Angela L. TODD, Amina KHAMBALIA and Christine L. ROBERTS Clinical and Population Perinatal Health Research, Kolling Institute of Medical Research, University Department of Obstetrics and Gynaecology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
Background: American evidence suggests women are not well informed about the optimal duration of pregnancy or the earliest time for safe birth. Similar evidence does not exist in Australia. Aims: To explore pregnant women’s beliefs about the duration of pregnancy and the earliest time for safe birth, and to compare the results with US data. Methods: A cross-sectional survey of pregnant women attending antenatal clinics at four public hospitals in Sydney, Australia, included information on maternal and pregnancy characteristics, and two questions exploring women’s beliefs about the duration of pregnancy, and the earliest time for safe birth. Responses were grouped as: late preterm (34– 36 weeks), early term (37–38 weeks) and full term (39–40 weeks). Results: Of the 784 surveyed women, 52% chose 39–40 weeks as the duration of a full-term pregnancy, while for the earliest time for safe birth, 10% chose 39–40 weeks and 57% chose 37–38 weeks. Some maternal characteristics were associated with women’s beliefs, including having a medical and/or pregnancy complication, country of birth, level of education, employment status and attending a tertiary hospital. The associations were different for each question. In comparison with US studies, Australian women were more likely to choose later gestations for both the duration of pregnancy and the earliest time for safe birth. Conclusions: A significant proportion of women believe that full-term pregnancy and earliest time for safe birth occur before 39 weeks, suggesting opportunities for better communication about the benefits and risks of birthing at different gestations. Key words: beliefs, gestational age, pregnancy, survey, term.
Introduction Growing evidence indicates that the five weeks of ‘term’ pregnancy from 37 to 41 weeks are not homogenous for perinatal risk.1–6 Compared with births at 39–41 weeks, ‘early-term’ births (37–38 weeks) have a greater risk of neonatal morbidity, with increased risk of neonatal sepsis, hypoglycaemia, need for mechanical ventilation and admission to neonatal intensive care.7 An Australian study of planned births found a stepwise increase in severe neonatal morbidity with each decreasing week below 39 weeks: following prelabour caesarean, from 2% at
Correspondence: Prof Christine L. Roberts, Clinical and Population Perinatal Health Research, Kolling Institute of Medical Research, University Department of O&G, Building 52, Royal North Shore Hospital, St Leonards, NSW 2065, Australia. Email: [email protected] Received 28 May 2014; accepted 25 August 2014.
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39 weeks to 8% at 37 weeks, and following labour induction, from 2% to 5%, respectively.8 Concurrent with these findings is the steady left shift in gestational age at birth towards this ‘early-term’ group in many developed countries.9–12 This raises concerns for the physiological maturity of neonates as well as maternal perceptions of ‘normal’ birth. In 2013, the USA officially redefined term pregnancy and separated ‘early-term’ (37–38 weeks), ‘fullterm’ (39–40 weeks), late-term (41 weeks) and post-term (42+ weeks) births;13 similar formal changes have not been echoed in Australia suggesting a lag in translation of research into policy and practice. Nonetheless, Australian and international obstetric organisations have recognised the increased perinatal risk associated with ‘early-term’ birth and introduced guidelines to encourage postponing planned deliveries until 39 weeks.14–16 Despite the recommendations, clinicians and expectant mothers may have differing opinions about the optimal timing for a baby’s birth. With planned births reported to be increasing worldwide, exploring women’s beliefs about the duration of pregnancy
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists The Australian and New Zealand Journal of Obstetrics and Gynaecology
Beliefs about pregnancy duration and safe birth
and perinatal risks will help identify knowledge gaps that need to be addressed.12,17,18 Currently, two studies in the United States have explored women’s understanding of the duration of pregnancy and timing of birth. A study by Goldenberg and colleagues19 explored women’s beliefs about the duration of ‘full-term’ pregnancy. This study and another, the Listening to Mothers III study by Declercq and others,20 examined women’s beliefs about the earliest time for safe birth of the baby. The results suggest American women are not well informed about the optimal duration of pregnancy or the earliest time for safe birth, with significant proportions choosing preterm gestations. To our knowledge, no comparable Australian study has been undertaken. The aims of this study were to determine the proportion of pregnant women who identified the duration of fullterm pregnancy and the earliest time for safe birth as 3940 weeks, to examine whether maternal characteristics were associated with women’s responses, and to compare our results with those reported by the two US studies.19,20
Materials and Methods A cross-sectional survey was conducted among pregnant women attending antenatal clinics in four public hospitals in Sydney, Australia. Two of the four participating hospitals provide tertiary level obstetric and neonatal care, and two are urban district hospitals. Women were surveyed during antenatal visits on random week days between July and December 2012. Pregnant women of any gestation, who had not completed the survey previously, were eligible to participate. Women were approached by the lead author or a research midwife not involved in their medical care and given verbal and written information about the study. Women who could read English and who consented to participate completed the survey while waiting for their antenatal appointment, and returned the survey to the recruiter or a marked return box. The self-administered, anonymous and quick-tocomplete (~five minutes) survey was developed based on existing literature, other survey instruments,12,17,19 and discussions with researchers, obstetricians and midwives. The survey was pilot-tested with 10 pregnant women and 30 women of childbearing age to ensure readability and clarity. Minimal wording changes were made. The survey consisted of 26 questions, including items about the woman’s current pregnancy, medical and obstetric history and demographic information. The woman’s responses to uncertainty were assessed using three previously validated items.21 Two related to cognitive uncertainty: ‘I like to have things under control’, and ‘I like to plan ahead in detail rather than leave things to chance’. A third item measured emotional uncertainty: ‘I get worried when a situation is uncertain’. Each uncertainty item was presented with a five-point Likert response scale (ranging from 1 = ‘strongly disagree’ to 5 = ‘strongly agree’). In
addition, two questions, that are the focus of this paper, explored the woman’s beliefs about the duration of fullterm pregnancy and the earliest time for safe birth. To allow direct comparison, the questions reported by Goldenberg and colleagues, and used in both US studies, were exactly replicated, including the response options of individual gestational weeks from 34 to 40 weeks.19,20 The questions were: ‘At what gestational age do you believe the baby is considered full term?’ (Full Term Gestational Age), and ‘What is the earliest point in the pregnancy that it is safe to deliver the baby, should there be no other medical complications requiring early delivery?’ (Earliest Safe Birth Gestational Age). Despite potential ambiguity around the meaning of the word ‘safe’, we retained the exact wording for comparison purposes.
Analysis Survey data were analysed using frequency tabulations and contingency table analyses. Univariate analysis, using v2 tests, examined the impact of maternal and pregnancy characteristics on the women’s responses to the two survey questions about Full Term Gestational Age and Earliest Safe Birth Gestational Age. Multivariate logistic regression analysis was used to examine the association between explanatory variables and the odds of women selecting the later-preterm or early-term gestations compared to the full-term gestations (reference group) for Full Term Gestational Age and Earliest Safe Birth Gestational Age. Explanatory variables included maternal and obstetric characteristics that may influence women’s knowledge and beliefs about pregnancy and birth: maternal age, gestation at time of survey, parity, multiple pregnancy, medical or pregnancy complications, country of birth, education level, employment status, district versus tertiary hospital for maternity care, expecting a caesarean section, and the three uncertainty items (women uncomfortable with uncertainty may be more likely to seek out information about pregnancy and birth). Gestational age at previous birth was also examined among multiparous women. Each of the explanatory variables was included in the model and variables with least significance were progressively removed (backward stepwise selection) from the model until all remaining covariates were statistically significant (two-tailed P < 0.05). Results are presented as odds ratio with 95% confidence intervals. All analyses were performed using SAS, version 9.3 (SAS Institute, Cary, NC, USA). Ethics approval was granted by the Northern Sydney Local Health District Human Research Ethics Committee.
Results A total of 850 women were invited to participate, of whom 784 completed the survey (response rate 92%). Reasons for declining included language difficulties, not interested, and busy caring for child/ren. The majority of surveyed women were 25 years of age or over (95%), held a
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
157
L. Y. Zhang et al.
university degree or higher (62%), and were more than 24 weeks gestation at the time of the survey (71%) (Table 1). Most women agreed or strongly agreed with the three uncertainty items, suggesting a preference for both cognitive and emotional certainty. Due to the small numbers of women choosing the option of ‘strongly disagree’, this group was combined with the ‘disagree’ group in further analyses. The majority of women chose a gestational age of 37 or more weeks as the Full Term Gestational Age, with 41% nominating 37–38 weeks and 52% nominating 39– 40 weeks. Only 7% nominated a Full Term Gestational Age before 37 weeks (Fig. 1). For the Earliest Safe Birth Gestational Age, 34% chose 34-36 weeks, 57% chose 37-38 weeks and 10% chose 39–40 weeks (Fig. 1).
Table 1 Characteristics of survey respondents (n = 784) Characteristic
N (%)
Maternal age (years)
DOI: 10.1111/ajo.12263
Original Article
Women’s beliefs about the duration of pregnancy and the earliest gestational age to safely give birth Lillian Y. ZHANG, Angela L. TODD, Amina KHAMBALIA and Christine L. ROBERTS Clinical and Population Perinatal Health Research, Kolling Institute of Medical Research, University Department of Obstetrics and Gynaecology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
Background: American evidence suggests women are not well informed about the optimal duration of pregnancy or the earliest time for safe birth. Similar evidence does not exist in Australia. Aims: To explore pregnant women’s beliefs about the duration of pregnancy and the earliest time for safe birth, and to compare the results with US data. Methods: A cross-sectional survey of pregnant women attending antenatal clinics at four public hospitals in Sydney, Australia, included information on maternal and pregnancy characteristics, and two questions exploring women’s beliefs about the duration of pregnancy, and the earliest time for safe birth. Responses were grouped as: late preterm (34– 36 weeks), early term (37–38 weeks) and full term (39–40 weeks). Results: Of the 784 surveyed women, 52% chose 39–40 weeks as the duration of a full-term pregnancy, while for the earliest time for safe birth, 10% chose 39–40 weeks and 57% chose 37–38 weeks. Some maternal characteristics were associated with women’s beliefs, including having a medical and/or pregnancy complication, country of birth, level of education, employment status and attending a tertiary hospital. The associations were different for each question. In comparison with US studies, Australian women were more likely to choose later gestations for both the duration of pregnancy and the earliest time for safe birth. Conclusions: A significant proportion of women believe that full-term pregnancy and earliest time for safe birth occur before 39 weeks, suggesting opportunities for better communication about the benefits and risks of birthing at different gestations. Key words: beliefs, gestational age, pregnancy, survey, term.
Introduction Growing evidence indicates that the five weeks of ‘term’ pregnancy from 37 to 41 weeks are not homogenous for perinatal risk.1–6 Compared with births at 39–41 weeks, ‘early-term’ births (37–38 weeks) have a greater risk of neonatal morbidity, with increased risk of neonatal sepsis, hypoglycaemia, need for mechanical ventilation and admission to neonatal intensive care.7 An Australian study of planned births found a stepwise increase in severe neonatal morbidity with each decreasing week below 39 weeks: following prelabour caesarean, from 2% at
Correspondence: Prof Christine L. Roberts, Clinical and Population Perinatal Health Research, Kolling Institute of Medical Research, University Department of O&G, Building 52, Royal North Shore Hospital, St Leonards, NSW 2065, Australia. Email: [email protected] Received 28 May 2014; accepted 25 August 2014.
156
39 weeks to 8% at 37 weeks, and following labour induction, from 2% to 5%, respectively.8 Concurrent with these findings is the steady left shift in gestational age at birth towards this ‘early-term’ group in many developed countries.9–12 This raises concerns for the physiological maturity of neonates as well as maternal perceptions of ‘normal’ birth. In 2013, the USA officially redefined term pregnancy and separated ‘early-term’ (37–38 weeks), ‘fullterm’ (39–40 weeks), late-term (41 weeks) and post-term (42+ weeks) births;13 similar formal changes have not been echoed in Australia suggesting a lag in translation of research into policy and practice. Nonetheless, Australian and international obstetric organisations have recognised the increased perinatal risk associated with ‘early-term’ birth and introduced guidelines to encourage postponing planned deliveries until 39 weeks.14–16 Despite the recommendations, clinicians and expectant mothers may have differing opinions about the optimal timing for a baby’s birth. With planned births reported to be increasing worldwide, exploring women’s beliefs about the duration of pregnancy
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists The Australian and New Zealand Journal of Obstetrics and Gynaecology
Beliefs about pregnancy duration and safe birth
and perinatal risks will help identify knowledge gaps that need to be addressed.12,17,18 Currently, two studies in the United States have explored women’s understanding of the duration of pregnancy and timing of birth. A study by Goldenberg and colleagues19 explored women’s beliefs about the duration of ‘full-term’ pregnancy. This study and another, the Listening to Mothers III study by Declercq and others,20 examined women’s beliefs about the earliest time for safe birth of the baby. The results suggest American women are not well informed about the optimal duration of pregnancy or the earliest time for safe birth, with significant proportions choosing preterm gestations. To our knowledge, no comparable Australian study has been undertaken. The aims of this study were to determine the proportion of pregnant women who identified the duration of fullterm pregnancy and the earliest time for safe birth as 3940 weeks, to examine whether maternal characteristics were associated with women’s responses, and to compare our results with those reported by the two US studies.19,20
Materials and Methods A cross-sectional survey was conducted among pregnant women attending antenatal clinics in four public hospitals in Sydney, Australia. Two of the four participating hospitals provide tertiary level obstetric and neonatal care, and two are urban district hospitals. Women were surveyed during antenatal visits on random week days between July and December 2012. Pregnant women of any gestation, who had not completed the survey previously, were eligible to participate. Women were approached by the lead author or a research midwife not involved in their medical care and given verbal and written information about the study. Women who could read English and who consented to participate completed the survey while waiting for their antenatal appointment, and returned the survey to the recruiter or a marked return box. The self-administered, anonymous and quick-tocomplete (~five minutes) survey was developed based on existing literature, other survey instruments,12,17,19 and discussions with researchers, obstetricians and midwives. The survey was pilot-tested with 10 pregnant women and 30 women of childbearing age to ensure readability and clarity. Minimal wording changes were made. The survey consisted of 26 questions, including items about the woman’s current pregnancy, medical and obstetric history and demographic information. The woman’s responses to uncertainty were assessed using three previously validated items.21 Two related to cognitive uncertainty: ‘I like to have things under control’, and ‘I like to plan ahead in detail rather than leave things to chance’. A third item measured emotional uncertainty: ‘I get worried when a situation is uncertain’. Each uncertainty item was presented with a five-point Likert response scale (ranging from 1 = ‘strongly disagree’ to 5 = ‘strongly agree’). In
addition, two questions, that are the focus of this paper, explored the woman’s beliefs about the duration of fullterm pregnancy and the earliest time for safe birth. To allow direct comparison, the questions reported by Goldenberg and colleagues, and used in both US studies, were exactly replicated, including the response options of individual gestational weeks from 34 to 40 weeks.19,20 The questions were: ‘At what gestational age do you believe the baby is considered full term?’ (Full Term Gestational Age), and ‘What is the earliest point in the pregnancy that it is safe to deliver the baby, should there be no other medical complications requiring early delivery?’ (Earliest Safe Birth Gestational Age). Despite potential ambiguity around the meaning of the word ‘safe’, we retained the exact wording for comparison purposes.
Analysis Survey data were analysed using frequency tabulations and contingency table analyses. Univariate analysis, using v2 tests, examined the impact of maternal and pregnancy characteristics on the women’s responses to the two survey questions about Full Term Gestational Age and Earliest Safe Birth Gestational Age. Multivariate logistic regression analysis was used to examine the association between explanatory variables and the odds of women selecting the later-preterm or early-term gestations compared to the full-term gestations (reference group) for Full Term Gestational Age and Earliest Safe Birth Gestational Age. Explanatory variables included maternal and obstetric characteristics that may influence women’s knowledge and beliefs about pregnancy and birth: maternal age, gestation at time of survey, parity, multiple pregnancy, medical or pregnancy complications, country of birth, education level, employment status, district versus tertiary hospital for maternity care, expecting a caesarean section, and the three uncertainty items (women uncomfortable with uncertainty may be more likely to seek out information about pregnancy and birth). Gestational age at previous birth was also examined among multiparous women. Each of the explanatory variables was included in the model and variables with least significance were progressively removed (backward stepwise selection) from the model until all remaining covariates were statistically significant (two-tailed P < 0.05). Results are presented as odds ratio with 95% confidence intervals. All analyses were performed using SAS, version 9.3 (SAS Institute, Cary, NC, USA). Ethics approval was granted by the Northern Sydney Local Health District Human Research Ethics Committee.
Results A total of 850 women were invited to participate, of whom 784 completed the survey (response rate 92%). Reasons for declining included language difficulties, not interested, and busy caring for child/ren. The majority of surveyed women were 25 years of age or over (95%), held a
© 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
157
L. Y. Zhang et al.
university degree or higher (62%), and were more than 24 weeks gestation at the time of the survey (71%) (Table 1). Most women agreed or strongly agreed with the three uncertainty items, suggesting a preference for both cognitive and emotional certainty. Due to the small numbers of women choosing the option of ‘strongly disagree’, this group was combined with the ‘disagree’ group in further analyses. The majority of women chose a gestational age of 37 or more weeks as the Full Term Gestational Age, with 41% nominating 37–38 weeks and 52% nominating 39– 40 weeks. Only 7% nominated a Full Term Gestational Age before 37 weeks (Fig. 1). For the Earliest Safe Birth Gestational Age, 34% chose 34-36 weeks, 57% chose 37-38 weeks and 10% chose 39–40 weeks (Fig. 1).
Table 1 Characteristics of survey respondents (n = 784) Characteristic
N (%)
Maternal age (years)
