Epidemiologic data from around the world show that depression is approximately twice as common in women than in men and that its first onset peaks during the childbearing years.1 The pregnancy and postpartum period may especially challenge a woman's mental health. Approximately 10–15% of women suffer from depressive illness during pregnancy or the first year postpartum.2,3 Depression may have a negative effect on the woman's social and personal adjustment, her marital relationship, and the mother-infant interaction.
Postpartum depression is frequently preceded by antepartum depression and anxiety.2,4 Postpartum depression is probably not associated with adverse obstetric and neonatal outcome.5–7 However, both antepartum and postpartum mood disorders represent separate risks for behavioral and emotional problems in the infant and developing child.8,9 Antepartum and postpartum mood disorders may also act in an additive manner. The effects of antepartum depression on pregnancy outcome are controversial, and difficult to compare owing to differences between study populations and the use of different rating scales and criteria used to define depression during pregnancy.10–14 The hypothesis of this population-based study was that women with antepartum depression constitute a vulnerable group with an increased risk for adverse obstetric and neonatal outcome.
MATERIALS AND METHODS
The Swedish antenatal health care system reaches almost 100% of all pregnant women.15 The antenatal care clinics provide regular check-ups on women's physical and psychological health during pregnancy and puerperium. The same percentage is valid for deliveries, because there are no private maternity hospitals in the study area, and home deliveries are rare.
The original sample in the present study comprises the total population of pregnant women consecutively registered at the antenatal care clinics in 4 communities in the southeast region of Sweden.2 The communities and their catchment areas have a population of more than 500,000. The communities cover a mixed sociodemographic structure with industrial, high-technological, educational, and farming areas. Enrollment took place in separate 3-month periods for each of the 4 communities during 1997–1999. The eligible women were approached in gestational week 35–36 and received both written and oral information by their midwife before giving consent. The only exclusion criterion was inability to understand Swedish. A total of 1,558 women were approached. Sixty-nine (4.4%) women declined to participate in the study. This group of women was equally distributed geographically and in age compared with the participating women. From the remaining 1,489 women, all women with depressive symptoms on the Edinburgh Postnatal Depression Scale at gestational week 35–36 were selected as an index group (n = 259). Two hundred fifty-nine women with no depressive symptoms on the Edinburgh Postnatal Depression Scale antepartum or postpartum were randomly chosen as the reference group. Records from 7 index women were not found. The Edinburgh Postnatal Depression Scale is a 10-item self-report scale specifically designed to screen for postpartum depression in community samples.16 Each item is scored on a 4-point scale (0–3), with the minimum and maximum total score ranging from 0 to 30, respectively. The scale rates the intensity of depressive symptoms present within the previous 7 days. The Edinburgh Postnatal Depression Scale has been translated into at least 11 languages,17 including Swedish.18 Validity of the Swedish version of the scale has been tested, and the findings were identical or similar to earlier studies.19 Cox et al16 proposed a cutoff level of 10 if the test is to be used for screening purposes in the postpartum period. Although the Edinburgh Postnatal Depression Scale cannot confirm a diagnosis of depression, when selecting this threshold, the sensitivity for the detection of major depression is almost 100%, and the specificity is 82%.20 The Edinburgh Postnatal Depression Scale has also been validated for use in a pregnant population.21 For antepartum screening, a cutoff level of 13 is recommended to identify all women with major depression.21 To ensure that no cases of minor depression were missed, we chose the original cutoff level of 10.21 The reason for this was that even a minor depression might influence the pregnancy outcome. In the original study, the prevalence of depressive symptoms was 17% at gestational week 35–36, 13% at 6–8 weeks postpartum, and unaltered at 6 months postpartum.2 The prevalence of depressive symptoms did not differ among the communities within each assessment.2
All data related to pregnancy, delivery, and the puerperium were registered in the standardized Swedish antenatal, delivery, and neonatal records. The authors manually extracted data from the records. In multiparas, medical records from earlier pregnancies were also included. The following data were collected: age, parity, marital status, occupation, number of induced abortions, miscarriages, and extrauterine pregnancies, and any history of infertility, psychiatric disorders, or obstetric complications such as acute or elective cesarean deliveries, instrumental delivery, perineal tears, excessive bleeding, premature delivery, or preeclampsia. Some data concerning sociodemographics or obstetric and gynecologic history were not found in the records of 9 women.
Actual chronic medical diseases, number of visits at the antenatal care clinics before delivery (midwife and obstetrician), pregnancy complications (preeclampsia, hyperemesis, back pain, vaginal bleeding, premature contractions), psychiatric disorders, fear of delivery, and sick leave during pregnancy were included. Perinatal events were also obtained.
All analyzes were performed using the SPSS 11.5 (SPSS Inc., Chicago, IL). The t test was used for variables with approximately normal distribution and the χ2 test was used when analyzing the categorical variables. The effect of sociodemographic variables and variables related to gynecologic or obstetric history and pregnancy on antepartum depressive symptoms were estimated through multiple logistic regression analyses. Statistical significance was defined as two-tailed P values using a significance level of 5%. The study was approved by the Regional Ethics Committee for human research of the Faculty of Health Sciences, Linköping University (No. 97133).
The distribution of sociodemographic variables is shown in Table 1. Women with antepartum depressive symptoms were more often multiparas, and there was a tendency toward being a single mother.
In Tables 2 and 3, we describe prior medical history with focus on gynecologic and obstetric data. In primiparas with antepartum depressive symptoms, no differences were found (Table 2). The multiparas with antepartum depressive symptoms were more likely to have a history of obstetric complications in past pregnancies, chronic medical disease, or miscarriage (Table 3).
Complications during the present pregnancy were significantly more frequent in the antepartum-depressed group of women (Tables 4 and 5). Because the women included in this study were enrolled during pregnancy weeks 35–36, there are no premature deliveries in this sample; however, women with antepartum depressive symptoms had a shorter gestational length. This difference was still evident when controlling for parity (P < .001).
Antepartum-depressed women also had a shorter duration of the second stage of labor. This difference disappeared when analyses were done separately for primiparas (P = .078) and multiparas (P = .808). No differences were found among all other delivery data presented in Table 6. Data concerning the puerperium and neonatal health were equally distributed between the index and reference groups (Table 7).
We investigated whether an antepartum score of 13 or more on the Edinburgh Postnatal Depression Scale (ie, women with major depressive symptoms) would affect the results of the same analyses described earlier, but no further information was gained. Of the 259 women with depressive symptoms during late pregnancy, 46.2% also had depressive symptoms at 6–8 weeks or 6 months postpartum or both.
In this population-based study, we present a wide range of data connected with women experiencing antepartum depressive symptoms. An advantage of this study is the fact that we had reached the total pregnant population at the time of the study, and those data were extracted from standardized medical records and not from maternal recall. The number of women who declined to participate was low (4.4%). Another strength is that this study includes prior medical, gynecologic, and obstetric history combined with data from the present pregnancy and delivery.
Two previous studies have shown that antepartum depression, anxiety, and stress are related to deteriorated obstetric and neonatal outcome, such as premature delivery and growth restriction in socially disadvantaged populations.10,11 However, a Scandinavian study by Hedegaard et al12 found no link between maternal antepartum psychological distress and fetal growth restriction. In a prospective study of Chinese women, Chung et al13 found that depression in the third trimester was associated with an increased risk for use of epidural analgesia, operative deliveries, and admission to neonatal care units. In contrast, Wu et al14 found no relationship between mode of delivery and depressive symptoms during the third trimester, but the response rate in the study was only 44%, which limits the validity of the results.
Our results show that, compared with nondepressed pregnant women, the antepartum-depressed women included in this study were more often multiparas with a history of obstetric complications. The women with depressive illness antepartum also had more somatic pregnancy complications (eg, premature contractions, back pain). Psychiatric disorders and fear of delivery were more frequent as well. Although there was no difference in the frequency of delivery and perinatal complications between the groups, severe complications were rare and our sample size might be too small to detect such a difference.
Some earlier studies suggest that perceived maternal strain and stressful life events lead to shorter pregnancy duration.22,23 We found a shorter gestational length of 1 week among the women with antenatal depressive symptoms, which is an interesting finding but may be regarded as clinically irrelevant.
Although the Edinburgh Postnatal Depression Scale is not diagnostic, it is a valid measurement of affective morbidity, and its main feature is the exclusion of items that might reflect physical discomfort and thus confuse depression with the somatic effects of pregnancy and childbirth.2,17 To make sure that we included cases of minor and major depression, we primarily chose a cutoff level of 10. Because a higher cutoff value might have a greater impact on the results, we also analyzed the cutoff level of 13 for major depressive symptoms, but did not gain any further information.
A potential weakness in this study is the enrollment at gestational week 35–36, which excludes almost all premature deliveries; however, the frequency of antepartum depressive symptoms is known to increase during the course of pregnancy, and an earlier enrollment most likely would have ruled out some women with antepartum depression.4 Another group of women who did not participate and who theoretically could have influenced the results were immigrants and refugees who did not understand Swedish. The results did not confirm our hypothesis that women with antenatal depressive symptoms have an adverse obstetric or neonatal outcome. Nevertheless, these women are obviously more vulnerable and important to identify because almost 50% continued to be depressed postpartum.2 Future research should therefore focus on treatment strategies for affective disorders during pregnancy, with a follow-up of the mother and child postpartum.
A plausible explanation for the normal pregnancy outcome might be that all women in this study received routine management at the antenatal care clinics and both groups of women had an equal attendance rate, which means that despite any psychosocial disadvantage and medical or psychiatric disease, the pregnancy care and surveillance was the same. In Sweden, with free antenatal and perinatal care, antenatal depression does not seem to be a risk factor for adverse pregnancy outcome.
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