Pre-pregnancy weight loss associations with prenatal and postpartum mental health conditions: A retrospective cohort study.

Background: Obesity is a risk factor for adverse outcomes during and following pregnancy. Most women are advised to lose weight prior to becoming pregnant, to help alleviate complications including prenatal and postpartum depression and anxiety. Yet, no studies have examined how the process of losing weight prior to pregnancy interacts with the development of prenatal and postpartum mental health disorders.The objective of the study was to determine if women with pre-pregnancy weight loss (≥10%) vs. those who do not, in the two years prior to pregnancy, have a lower risk for new onset prenatal and postpartum mental health conditions. Methods: This retrospective cohort study used data from the Virtual Data Warehouse of a large Midwestern, U.S. based hospital system. The final sample consisted of 6,085 female patients of reproductive age that had given birth between 10/1/2011-6/30/2020 and had two recorded weights in the year prior to conception. Univariate analysis between weight loss and outcome variables (pre-natal and post-partum depression and anxiety) and multivariate analysis using logistic regression was conducted for variable significant on univariate analysis. Results: On univariate analysis, women with pre-pregnancy weight loss had increased odds of post-partum depression (OR=1.47, 95%CI=1.03-2.10), though decreased odds of prenatal anxiety (OR=0.59, 95% CI 0.33-0.90). After controlling for confounders in the multivariate analysis, there was not a significant difference in the odds of post-partum depression; however, women who lost weight had approximately half the odds of having prenatal anxiety than those who did not lose weight (OR=0.54, 95%CI=0.33-0.90). Discussion: The experience of achieving weight loss prior to pregnancy may foster a sense of agency within pregnant women, helping them to reduce their experience of pre-natal anxiety. Providers could engage in patient conversations around weight loss and mental health management in a strengths-based framework to continue to foster this sense of agency. Conclusion: Anxiety and depression were uniquely related to pre-pregnancy weight loss. Pre-pregnancy weight loss was associated with lower odds of prenatal anxiety and higher odds of postpartum depression. These results highlight the need for real world examination of pre-conception treatment recommendations and their association with non-physical health-based outcomes.