Pre-pregnancy Obesity and Postpartum Depression: a Predictive Model

Purpose/Aims: The purpose of this study was to test a biobehavioral model of the relationship between pre-pregnancy body mass index (BMI) and symptoms of depression at four weeks postpartum. It was hypothesized that pre-pregnancy BMI is positively associated with symptoms of depression at four weeks postpartum and mediated by third trimester pro-inflammatory markers (IL-6, TNF-α, and leptin) and biobehavioral markers of stress (symptoms of depression, perceived stress, and cortisol).                                                                                                                                                                       Rationale/Conceptual Basis/Background: Thirteen percent of new mothers suffer from postpartum depression (PPD) making it the most common complication of childbirth. In the nonpregnant population there is a positive relationship between obesity and symptoms of depression. Additionally, prenatal stress and prenatal depression are significant risk factors for PPD. An integrated model of the Psychoneuroimmunological Framework and the Transactional Model of Stress and Coping guided the study.                                                                                                                                                                                      Methods: A secondary analysis of data from a longitudinal, biobehavioral repeated measures study of women during the third trimester of pregnancy through six months postpartum was conducted. Descriptive statistics, correlations using Pearson’s r, principal component analysis, and path analysis with principal component (PC) variables were used to iteratively test the model.                                                                                                                                                                                  Results: Correlation analysis findings included a small correlation between pre-pregnancy BMI and IL-6 (r=0.22, p=0.018), a medium correlation between pre-pregnancy BMI and leptin (r=0.43, p=0.000), a high medium correlation between third trimester Edinburg Postnatal Depression Scale (EPDS) scores and EPDS scores at four weeks postpartum (r=0.48, p=0.000) as well as between third trimester Perceived Stress Scale (PSS) scores and EPDS scores at four weeks postpartum (r=0.49, p=0.000). Path analysis findings included a medium effect from pre-pregnancy BMI to the inflammation PC (standardized coefficient = .29, p = 0.001), the path from pre-pregnancy BMI to the stress PC had a significant small effect (standardized Coefficient = .19, p< 0.001), and there was a significant strong effect from the stress PC to EPDS scores at four weeks postpartum (standardized coefficient = .53, p<0.001). There was a very small, statistically insignificant total effect of pre-pregnancy BMI on EPDS scores at four weeks postpartum (standardized coefficient = .058).                                                                                                                                                                                   Implications: These findings add to the scientific knowledge regarding the association between pre-pregnancy BMI and increased levels of pro-inflammatory markers during pregnancy. This knowledge is important as there is also a growing body of evidence that increased levels of pro-inflammatory molecules are associated with adverse pregnancy outcomes. These findings also emphasize the need for a paradigm shift in perinatal care from reactionary care to preventative care with risk screening for PPD beginning in the preconceptual period or the first trimester of pregnancy. Future research is indicated to investigate the feasibility of perceived stress as measured by the PSS as a predictor of symptoms of PPD.  

Funded in part by an award from the National Institutes of Health (RO1NR011278)