Association between body mass index and chronic hypertension in patients with hypertension disorders of pregnancy one-year postpartum.

Objectives: To determine the association between body mass index (BMI) and chronic hypertension (CHTN) one-year postpartum following pregnancies complicated by hypertensive disorders of pregnancy (HDP).

Study Design: A retrospective cohort study of patients with HDP (gestational hypertension or preeclampsia) in a single Midwestern academic center from 2014 to 2018. The primary outcome was CHTN at one-year postpartum, defined as systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 80 mmHg or taking antihypertensive medication at one-year postpartum. The primary exposure variable was BMI at one-year postpartum, categorized as underweight (<18.5 kg/m), normal (18.5-24.9 kg/m), overweight (25-<30 kg/m), and obese (≥30 kg/m) and as continuous BMI variable. Descriptive statistics and adjusted logistic regression analysis were performed.

Results: Out of 596 patients with HDP included in this analysis, 275 (46.1 %) had CHTN one-year postpartum. Mean one-year postpartum BMI was 27.9 ± 5.2 kg/m. Prevalence of CHTN at one-year postpartum was higher in obese (38.1 %) and overweight (30.0 %) groups compared to the normal weight group (29.9 %), p < 0.001. In multivariate logistic regression, obesity at one-year postpartum, compared to normal, was associated with 73 % higher likelihood of CHTN following HDP (adjusted OR 1.73, 95 % CI 1.06-2.84). With BMI as a continuous variable, each unit increase in BMI one-year postpartum was associated with 6 % higher likelihood of CHTN (adjusted OR 1.06, 95 % CI 1.02-1.15).

Conclusions: Obesity at one-year postpartum following HDP was associated with a higher risk of CHTN compared with normal BMI. Weight is a modifiable risk factor that should be targeted in postpartum interventions to reduce cardiovascular disease following HDP.