Prevalence of anxiety and depressive symptoms among obese pregnant and postpartum women: an intervention study

Obesity has been reported to have a negative impact on physical health and psychological well-being [1, 2]. There is an association between depression, anxiety and obesity, and several studies have shown that obese women are more vulnerable than obese men to the development of psychiatric and psychological disorders [3–9]. A number of studies have investigated symptoms of depression and anxiety during and after pregnancy [10–13]. Josefsson et al. found in a longitudinal study that the prevalence of depressive symptoms was 17% during late pregnancy and 13% postpartum [10]. Rubertsson et al. found a prevalence of 14% in early pregnancy and 11-14% during the first year postpartum [12]. Both anxiety and depression during pregnancy are strong predictors for postpartum depression [11, 13].

Obesity during pregnancy is also associated with a high risk for medical complications [14]. Maternal obesity is, for example, associated with an increased risk for preeclampsia and gestational diabetes mellitus as well as for complications during delivery. In addition, there is an increased risk for antepartum stillbirth and macrosomia [14]. Psychological health and well being during and after pregnancy among obese women have not been thoroughly investigated. The association between body mass index (BMI) and self-reported postpartum depressive symptoms was investigated in a study in the United States [15]. In a stratified random sample of approximately 600 obese women, 30.8% reported moderate or greater depressive symptoms compared with 22.8% in a similar sample consisting of about 1800 normal weight women, two to six months postpartum. Krause and co-workers investigated the prevalence of postpartum depression among approximately 500 overweight and obese postpartum women, recruited from a randomized controlled intervention study designed to encourage postnatal weight loss through increased physical activity and decreased caloric intake [16]. In this study the prevalence of depression was 9.2% and there was no relationship between BMI and postpartum depression.

In a recent prospective intervention study primarily designed to minimize obese women's weight gain to less than 7 kg during pregnancy, we showed that the women who received a structured motivational and behavioral treatment combined with regular physical exercise had a significantly lower weight gain compared with a control group of obese pregnant women who received regular antenatal care without any negative effect on delivery or neonatal outcome [17]. Since it is known that obesity can have a negative influence on psychological well-being, it is important to investigate if the state of psychological well-being of obese pregnant women attending a weight gain restriction program with a focus on behavioral changes differs from psychological well being in a control group. There are to our knowledge no intervention studies designed to accomplish weight-gain restriction for obese pregnant women that have also examined the women's psychological health status.

We hypothesized that pregnant obese women attending an intervention program, based on motivational and behavioral treatment and with the primary aim of reducing weight-gain during pregnancy, would show fewer depressive and anxiety symptoms throughout pregnancy and postnatally than women not attending such a program. Hence, the aim of this study was to investigate psychological well-being measured as symptoms of depression and/or anxiety among obese pregnant women attending a weight gain restriction program and to make comparisons with a control group receiving traditional antenatal care.

The Swedish antenatal health care system reaches almost 100% of all pregnant women. The antenatal- and delivery care are free of charge. At the antenatal care clinics (ANC) healthy pregnant women are recommended to attend the regular antenatal program with seven to nine visits to a midwife, and, if needed, arrange for extra appointments with an obstetrician and/or with the midwife.

Subjects

During the period November 2003 to December 2005 a total of 317 obese pregnant women in early pregnancy were consecutively registered at the ANC in the city of Linköping and surrounding area. The inclusion criteria for the study were BMI ≥30 and Swedish-speaking. We excluded all women with pre-pregnant diagnosis of diabetes, thyroid dysfunction or a psychiatric disease treated with neuroleptic drugs. After excluding women who did not meet the inclusion criteria, had miscarriage or legal abortion or moved out from the catchment area in early pregnancy, 230 women were eligible and invited to participate. A total of 70 women refrained from participation and five women dropped out during the intervention. One hundred fifty-five women (67.4%) completed the intervention. This subsample consisted of 151 obese women with singleton pregnancies (Figure 1).

All obese pregnant women (n = 437) consecutively registered during the same period at the ANC in two nearby cities with surrounding area, formed a control group. The inclusion- and exclusion criteria were the same as for the intervention women. Thereafter women who had a miscarriage or legal abortion were excluded. Finally, 385 women were eligible and invited to participate. Of this total, 177 women refrained from participation and 15 women dropped out during pregnancy. One hundred ninety-three women (50.1%) completed the participation. This subsample consisted of 188 obese women with singleton pregnancies (Figure 1).

In a previous study, no differences were found between the intervention group and the control group regarding age, parity, marital status, smoking, BMI and occupation [17]. The women in the intervention group reported a higher education level than the women in the control group (p = .044). The women who refrained from participation in both groups were, on average, one year younger than the women who participated in the study (29 vs. 30 years, p = .018). Moreover, those who declined to participate were smokers and had previous children to a higher extent than those participating in the study. For a detailed description of the study participants, see Claesson et al [17].

All data related to pregnancy, delivery and the puerperium were registered in the standardized and identical Swedish antenatal pregnancy, delivery, and neonatal records. The data were manually extracted from the records. This study was approved by the Human Research Ethics Committee, Faculty of Health Sciences, Linköping University.

In this prospective intervention study with a primary aim of minimizing gestational weight gain of obese women, the prevalence of symptoms of anxiety and depression during pregnancy varied between 18% and 25% within the intervention- and control group. The postnatal prevalence of symptoms of anxiety and depression varied between 9% and 11% within these two groups. No differences were found between the groups. Around 4-5% of all women had symptoms of anxiety, 4-6% had symptoms of depression and only a few women presented symptoms of both anxiety and depression at all three assessments. There was no relationship between symptoms of anxiety, depression and weight gain during pregnancy as measured on three different occasions. In both groups, women with a lower level of education and without employment showed symptoms of anxiety and depression more often than women with a higher level of education and gainful employment. After adjustment for socio-demographic variables and pregnancy, delivery and neonatal complications there were no differences in the prevalence of symptoms of anxiety between the groups. However, there was a relation between complications during pregnancy and symptoms of depression in the control group.

We hypothesized that participation in the intervention program would increase psychological well-being due to weekly motivational support and would therefore result in a lower prevalence of anxiety or depressive symptoms than would have resulted without the program. This hypothesis was not confirmed. Neither did we find any relation between weight gain during pregnancy or postnatal weight and the prevalence of symptoms of anxiety or depression among obese women in the intervention group and the control group. One can consider whether socioeconomic factors such as unemployment and or a low level of education compose a stress on the individual and the effect this has. It is possible, as suggested by Britton [28], that mothers with a low level of education may have a tendency towards developing high levels of anxiety because they are less able to handle the demands and expectations placed on them during the period when they take on the maternal role. One may also speculate if worrying about the future, as concerns both employment and household economy, may lead to symptoms of both anxiety and depression.

The prevalence of anxiety in a general population of pregnant women during and after pregnancy has been investigated in earlier studies [13, 29, 30]. In our study the prevalence of symptoms of anxiety among obese pregnant women was around 23% during pregnancy, which is in accordance with findings by other authors [13, 30]. Breitkopf et al. assessed anxiety symptoms among pregnant, non-pregnant and postnatal women, and found that the anxiety scores were lower among postnatal women in comparison with pregnant and non-pregnant women even after controlling for depressive symptoms [29]. This is in line with our results where the symptoms of anxiety were lower postpartum than during pregnancy. Nothing in our study indicates that obese pregnant or postnatal women have more symptoms of anxiety than are exhibited in the general pregnant population.

Several studies have investigated the prevalence of depressive symptoms during pregnancy and postpartum [10, 12, 31–34]. The EDPS has been used with different cut-offs for evaluating depressive symptoms [10, 12, 31, 33, 34]. The prevalence in these studies varies from 8% to 17% during pregnancy and 9% to 13% postpartum. A study that used the same cut-off on the EPDS for depressive symptoms as in this study found a prevalence of depressive symptoms during late pregnancy and postpartum similar to what we found [10].

Furthermore, two studies have investigated the impact of obesity on the risk for postpartum depression with differing results [15, 16]. In the study of LaCoursiere the woman was asked to assess her depressive symptoms' two - six months after delivery [15]. The five-level scale was from "not depressed at all" to "very depressed and had to get help". Answer on symptoms' level 'moderately' or more, indicated postnatal self-reported depression and was given by 31% of the obese women postpartum [15]. In the study of Krause et al., where the women completed the EPDS with a cut off of ≥13, six weeks postpartum, a prevalence of 9% among overweight and obese women postpartum was shown [16]. Our results at the postnatal measurement were in accordance with the findings in the study by Krause.

The relationship between antenatal and postnatal symptoms of depression has been investigated by Josefsson et al. who showed that 6% of the women had symptoms both during pregnancy and postpartum and this is in line with our findings [10]. The occurrence of depressive symptoms during and after pregnancy in relation to demographic characteristics in a general pregnant population has also been investigated [12, 16, 32, 33, 35]. These studies have shown an association between economic difficulties, low household income, unemployment, lower educational attainment and depressive symptoms [12, 16, 32, 33]. The connection between anxiety and depressive symptoms and maternal and neonatal outcome has been investigated [36–38]. A review by Alder and colleagues found elevated levels of anxiety and depression to be related to obstetric complications, preterm labor and alleviation of labor pain [36]. Vollebregt et al. investigated the association of preeclampsia and gestational hypertension with psychosocial stress among nulliparous in the first half of pregnancy and found that anxiety, pregnancy-related anxiety or depression had no effect on the incidence of preeclampsia and gestational hypertension [38]. Berle and co-authors reported a relationship between anxiety disorder during pregnancy and low Apgar score at one and five minutes, but no relationship was observed with low birth weight or preterm delivery [37]. We did not find any differences between the two groups of women in our study regarding the relationship between symptoms of anxiety and/or depression and pregnancy-, delivery- and neonatal complications. In the control group, however, there was a relationship between pregnancy complications and depressive symptoms at the assessment in late pregnancy.

This study was not randomized, which can be seen as an important limitation. In all scientific research it is important to control external factors and the environment has been found to exert a powerful influence on people's emotions and behavior [39] and careful consideration must be given to ensure that the intervention group and the control group will get treatment and care at the same setting. We chose therefore to use ANCs in two nearby cities to serve as controls. The antenatal programs in Sweden are standardized and almost identical concerning the management of the pregnancy, which ensures similar care at different ANCs. We were also able to control for several background characteristics that otherwise could confound the results. There was also a difference in the completion rates between the intervention- and control group. A total of five women in the intervention group dropped out compared with 15 women in the control group. Another limitation is that the number of questionnaires answered at the times of the three assessments differs to some extent between the intervention- and control group. Therefore some caution is advisable when generalizing these results. Furthermore, there are no data on prevalence of symptoms of anxiety and depression among women who declined participation. Despite these limitations there are some important findings in this study. To our knowledge this is the first intervention study that has investigated symptoms of anxiety and/or depression in an obese pregnant population. Since there are few studies that have investigated the relation between anxiety and depression among obese pregnant women especially in relation to a weight gain intervention program there is need for further work on this topic.

In conclusion, neither weight gain nor a weight gain restriction program during pregnancy seems to influence the prevalence of symptoms of anxiety or depression. Obese women who participated in this study do not run a higher risk for anxiety and/or depressive symptoms during pregnancy or postpartum, compared with a general pregnant and postnatal population.