(937) Lactation outcomes among gravidae with mild chronic hypertension

Friday, February 10, 2023

3:30 PM – 5:00 PM

Objective: Longer duration of breastfeeding reduces later cardiovascular morbidity and mortality, and may be of additional benefit in high-risk populations such as those with chronic hypertension (cHTN). Paradoxically, varying blood pressure (BP) control may limit initiation or duration of breastfeeding. We hypothesized that treatment to achieve BP < 140/90 during pregnancy and postpartum would alter rates of successful initiation and duration of breastfeeding.

Study Design: We performed a secondary analysis of the Chronic Hypertension and Pregnancy (CHAP) Trial. This was an open-label, multicenter, randomized trial where pregnant people (gravidae) with mild cHTN were randomized to receive antihypertensive medications with goal BP of < 140/90 (active treatment) or deferred treatment until BP > 160/105 (control). Primary outcome was ever and duration of breastfeeding. We performed bivariate analyses, log-binomial and cumulative logit regression models, adjusting for gestational age, enrollment body mass index (BMI), and postpartum discharge on antihypertensive medications.

Results: 1444 gravidae were included. Participants in the active treatment group had higher BMI class and earlier gestational age at enrollment, and (by design) were more often discharged on antihypertensives. Lactation outcomes did not differ by treatment group (Tables 1, 2). In the active treatment group, 563 (77.5%) initiated breastfeeding, and 297 (54.2%) breastfed for 6 weeks. Probability of ever breastfeeding (aRR 0.99, 95% CI 0.93–1.05), current breastfeeding at 6 weeks (aRR 1.01, 95% CI 0.94–1.10), and weeks of breastfeeding (aOR 0.87, 95% CI 0.68–1.12) did not differ by treatment group.

Conclusion: Among a cohort of gravidae with mild cHTN, lactation outcomes did not differ significantly by treatment group, suggesting that maintaining goal BP of < 140/90 is neither harmful nor beneficial for lactation goals. However, overall breastfeeding rates were less than the national average in this high-risk population, suggesting that increased lactation support is needed among gravidae with cHTN.

Primary Author(s)

Alison N. Goulding, MD, MSCR (she/her/hers)
Maternal-Fetal Medicine Fellow
Baylor College of Medicine
Houston, Texas, United States

Presenting Author(s)

Alison N. Goulding, MD, MSCR (she/her/hers)
Maternal-Fetal Medicine Fellow
Baylor College of Medicine
Houston, Texas, United States

Coauthor(s)

LA
Leah Antoniewicz, MD
Assistant Professor
Baylor College of Medicine
Houston, Texas, United States