Abstract Body: Introduction
Postpartum hypertension (ppHTN) affects approximately 50% of patients with a hypertensive disorder of pregnancy (HDP) and an additional 10% with a normotensive pregnancy. Isolated diastolic hypertension is particularly important as it is an indicator of cardiovascular risk among younger populations.
Hypothesis
Breastfeeding is protective against cardiometabolic disorders and we hypothesized that breastfeeding in the month after delivery decreases the risk of isolated diastolic ppHTN at 30-60 days postpartum.
Methods
We conducted a medical record-based cohort study of deliveries ≥20 gestational weeks from 2016-2018 at an urban safety-net hospital and restricted to patients with clinically obtained blood pressure (BP) measures between 30-60 days postpartum. Data on breastfeeding, including initiation and continuation, was extracted from both maternal and pediatric records and categorized as never, ≤13 days, or ≥14 days. Isolated diastolic ppHTN was defined as elevated diastolic BP (≥80mmHg) with normal systolic BP (<130mmHG). Logistic regression models were used to calculate the odds ratios (OR) and 95% confidence intervals (CI) for the association between breastfeeding and isolated diastolic ppHTN. Models were adjusted for sociodemographic and pregnancy characteristics and conducted separately among those with and without HDP.
Results
Among the 2,233 patients included, 56% were Black/non-Hispanic, 15% were Hispanic and most were insured by Medicaid (68%). A small proportion of patients never breastfed (6.4%), while 71.4% breastfed for ≤13 days and 22.2% breastfed for ≥14 days. Normotensive Pregnancy Cohort (n=1,672; 75%). Approximately 19% of these patients had isolated diastolic ppHTN. Compared to those who never breastfed, those who breastfed ≤13 days (OR:0.81, 95%CI: 0.49, 1.31) and those who breastfed ≥14 days (OR:0.76, 95%CI: 0.45, 1.29) had reduced odds of isolated diastolic ppHTN. In the adjusted model, estimates were slightly attenuated (≤13 days: OR:0.73 and ≥14 days: OR:0.67). HDP Cohort (n=561, 25%). Nearly a quarter (23.2%) of those with HDP had isolated diastolic ppHTN. A similar pattern between breastfeeding and isolated diastolic ppHTN was observed with those breastfeeding ≥14 days experiencing the largest reduction (OR:0.50; 95% CI: 0.22, 1.17).
Conclusions
Isolated diastolic ppHTN is common even among those with normotensive pregnancies and breastfeeding presents an opportunity to reduce its occurrence.