Introduction

In the USA, gestational diabetes mellitus (GDM) rates are increasing, affecting an estimated 6–7 % of pregnancies, with higher rates among Asian (8.14 %) and Latina (7.02 %) women, and women who are overweight or obese (Bardenheier et al. 2013). Recent GDM women (prior GDM (pGDM)) are at increased risk for developing type 2 diabetes mellitus (T2DM) compared to normoglycemic women (Halkoaho et al. 2010). As ethnic minority pGDM women comprise one of the highest risk groups for T2DM progression, these groups are increasingly targeted for diabetes prevention interventions that often require behavioral commitments to exercise, weight loss, and healthy eating. For low-income ethnic minority women, particularly non-English-speaking women, there may be important psychological and financial stressors that can interfere with adoption of diabetes prevention efforts in the absence of tailored support.

Given the increasing prevalence of GDM and T2DM, many practitioners are screening for diabetes earlier in pregnancy in order to develop effective management plans.Footnote 1 Earlier GDM screening raises questions about the impact of GDM, and of a GDM diagnosis, on mental health outcomes, primarily postpartum depression (PPD). About 10–12 % of women are affected by PPD, and while there is evidence of a bidirectional link between diabetes and depression, the link between GDM and the development of PPD is not well understood. Possible mechanisms to support an association include the effects of hyperglycemia and insulin on the thyroid and stress axis and the psychological burden of managing a chronic disease during and after pregnancy (Kozhimannil et al. 2009). In light of the increasing rates of GDM among Asians and Latinas and the uncertainty as to whether GDM places women at increased risk for PPD, we sought to summarize the current US literature on GDM and PPD, with a particular focus on studies with ethnic and minority populations and on demographic factors related to socioeconomic stressors.

Methods

Search strategies for four databases were conducted in collaboration with a professional librarian (Fig. 1). From 302 results, there were 60 duplicates and 242 unique articles. Two independent reviewers (SB and MH) evaluated abstracts, excluding editorials and case reports and studies of non-GDM diabetes and those with no temporality established regarding GDM and mental health symptoms, leaving 30 articles for full text screening. Eighteen were excluded after full text review, and three additional studies were identified, resulting in 15 articles. Additional quality criteria were then applied for the following: (1) presence of both GDM and non-GDM groups, (2) at least 50 participants in each group, and (3) description of recruitment strategy/participation rate, resulting in ten studies (Table 1). The three US studies that include details on ethnic groups are summarized in the Results. Additional non-US studies are included in Table 1 but are not discussed.

Fig. 1
figure 1

Summary of search strategy and article selection methods. The search and literature review was conducted between December 2012 and March 2013

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Table 1 Studies from the USA and from outside the country
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Results

Two large population-based studies using administrative data in New Jersey (Kozhimannil et al. 2009) and data from the Pregnancy Risk Assessment Monitoring System (PRAMS) survey in New York City (Liu and Tronick 2012) examined the association between GDM and PPD. Both include population-based samples with ethnicity-specific data. Kim et al. conducted a prospective assessment of an ethnically diverse sample of women receiving care at a publicly funded hospital in San Francisco (Kim et al. 2005).

Kozhimannil et al. (2009) conducted a retrospective review of Medicaid administrative data for 11,024 women delivering in New Jersey in 2004–2006. Inclusion required continuous enrollment in the state Medicaid program 6 months prior and 12 months after delivery. Diabetes was defined by an ICD-9 code diagnosis for T2DM (250) or GDM (6480) or filling a diabetes-related prescription. PPD was defined by an ICD-9 code for depressive, dysthymic, or depressive adjustment disorders or by a documented antidepressant prescription. Overall, 13.7 % of pGDM women had either PPD or depression during pregnancy. After adjusting for age, race, year of delivery, and preterm birth, compared with non-GDM women, GDM women who were taking insulin had nearly double the odds of depression [odds ratio (OR) 1.96; 95 % confidence interval (CI), 1.27–3.04]. Similar odds were reported for GDM women not taking insulin (OR = 1.72; 95 % CI, 1.11–2.66). Analysis controlling for prenatal depression during pregnancy also showed similar findings for PPD (OR 1.69; 95 % CI, 1.27–2.23). Although this study did not report ethnicity-specific results, participants were primarily non-white, including African-American (46 %) and “other” which included Latinas, Asians, and Native Americans (12.4–17.5 %). The strict criteria for PPD and GDM diagnosis strengthen the results of this study regarding an increased risk of PPD among ethnically diverse GDM women. Of note, though, is the number of eligible Latinas decreased from 44 to 8 % when the criteria for continuous Medicaid eligibility were applied.

Liu and Tronick (2012) examined PPD prevalence and risk factors for PPD among 3372 women following linkage of population-based birth certificate data and PRAMS data for 2004–2007. PRAMS surveyed women 2 to 4 months after delivery to characterize self-reported GDM and postpartum depression (“yes” to “Since your new baby was born, has a doctor, nurse, or health-care worker diagnosed you with depression?”). Results indicate that compared to white women, Asian and Hispanic women had significantly higher rates of PPD. In stratified analysis, sociodemographic and maternal stressors accounted for increased rates in PPD among blacks and Hispanics compared to whites, whereas API women were still 3.2 times more likely to report PPD. There was no association, however, between PPD and higher rates of GDM after controlling for sociodemographic variables. As discussed by the authors, one important limitation is that reported differences in PPD rates among ethnic groups may reflect differences in screening, diagnosis, or reporting bias in willingness to self-disclose PPD.

In the Women and Infants Starting Healthy (WISH) study, women with GDM and pregnancy-induced hypertension (PIH) were evaluated postpartum (Kim et al. 2005). Study measures included perceived health status changes from prepregnancy compared to postpartum measures for women with GDM (n = 64), PIH (n = 148), and those without a prenatal health condition (n = 1233). Health status measures included the Short Form-36 scales for physical function, vitality, and self-rated health and the Center for Epidemiologic Studies Depression Scale. Approximately two thirds of the study population was non-white, with Latinas, African-Americans, and Asians comprising the largest groups. Women with GDM and those without a prenatal health condition reported similar rates of postpartum depressive symptoms, which were high overall (14.1 and 13.5 %, respectively). A high proportion of GDM women reported having poor health status postpartum (18.7 %), which was significantly greater (p < 0.05) than women without a prenatal health condition (10.0 %). This study has a small sample but suggests that postpartum depressive symptoms are common in this population.

Discussion

The findings of the study of Kozhimannil et al. (2009) suggest a strong association between GDM and PPD among ethnically diverse low-income women, while the other studies provide support for high rates of PPD among all groups of women included in the studies. Taken together, these findings suggest that potentially greater risks for PPD among ethnically diverse low-income women warrant more careful study. For women with GDM, lifestyle changes and interventions that focus on a healthy diet, weight loss or maintaining a healthy weight, regular physical activity, and breastfeeding are especially important as they have been shown to prevent or delay the onset of T2DM (Halkoaho et al. 2010). However, as suggested by the findings in this review, it is critical to take into account the high prevalence of PPD symptoms in such tailoring, as PPD cannot only result in reduced adherence to dietary guidelines and decreased physical activity for the mother (Vernon et al. 2010) but can also affect a mother’s relationship with her newborn, which can lead to long-term sequelae for the child, including impaired cognitive development and poor emotional adjustment (Al-Shahrani et al. 2011a). Because the perinatal period has been identified as a “window of opportunity” for initiating lifestyle changes, integration of PPD screening and counseling for GDM women should be supported, as should tailoring supportive services to diverse populations. Such efforts can both reduce the burden of PPD and enable women to become active in prevention efforts to reduce the incidence of T2DM.