Pre-gestational BMI, obstetric violence, and perinatal mental health: a retrospective cohort study.

Abstract

Higher pre-pregnancy body mass index (BMI) has been associated with obstetric complications and proposed as a psychosocial risk factor for postpartum depression (PPD). However, its relationship with postpartum post-traumatic stress disorder (PP-PTSD) and perceived obstetric violence has not been sufficiently investigated. We aimed to examine the association between pre-pregnancy BMI and perinatal mental health outcomes. We conducted a retrospective cohort study in Spain in 2023 using a self-administered online questionnaire completed by 2363 women between one and six months postpartum. Outcomes included high perception of obstetric violence (CARE-MQ > p90), risk of PP-PTSD (PPQ ≥ p90), and PPD (EPDS ≥12). Pre-pregnancy BMI was categorized according to WHO criteria. Multivariable logistic regression models adjusted for sociodemographic, clinical, and obstetric confounders were used. Women with higher pre-pregnancy BMI had a higher frequency of medical interventions (induction of labor, oxytocin, regional analgesia) and more birth complications (aOR 1.69, 95% CI 1.21-2.34). Higher pre-pregnancy BMI was independently associated with increased risk of PPD (aOR 1.44, 95% CI 1.05-1.97), but not with PP-PTSD or perceived obstetric violence. Protective factors included older maternal age, higher income, attendance at childbirth preparation classes, adherence to the birth plan, skin-to-skin contact, and early initiation of breastfeeding. Complicated births and failure to adhere to the birth plan were associated with increased risk of experiencing at least one postpartum mental health problem. Higher pre-pregnancy BMI may be linked to increased vulnerability to postpartum depression. This relationship appears influenced by obstetric characteristics and care practices, underscoring the need for further research and for preventive strategies to improve respectful, stigma-free perinatal care for women with higher pre-pregnancy BMI. This study was funded by Instituto de Salud Carlos III (project PI22/00541) and co-funded by the European Union.