Status: Funded - Open
BACKGROUND: The US prevalence of chronic hypertension is 1-5% and rising. Chronic hypertension is associated with a 2-fold increased risk of several adverse outcomes including preterm birth, small-for-gestational delivery, and fetal and neonatal death. Identifying optimal therapeutic approaches to prevent adverse outcomes in pregnancies complicated by chronic hypertension is urgent. GAP: Results from the recently published Chronic Hypertension and Pregnancy (CHAP) trial showed that pregnant women randomized to antihypertensive treatment targeting a blood pressure <140/90mmHg had 18% reduced risk of a composite outcome compared to those receiving no treatment. How these results will translate to real-world outcomes is unknown. Strict eligibility criteria reduce generalizability of findings. Small RCT sample sizes did not permit study of rare outcomes or rigorous analysis of how the treatment effect varied across population subgroups. Randomization after pregnancy recognition prevented analysis of the effects of pre-pregnancy or early pregnancy antihypertensive use. HYPOTHESIS: We will use a target trial framework to emulate findings from the CHAP trial in an observational setting. We hypothesize that prenatal antihypertensive use will reduce risk of adverse outcomes compared to no treatment and that the strength of associations will vary by antihypertensive agent. Also, we hypothesize that associations will vary by sociodemographic characteristics, and that antihypertensive use will have stronger protective effects when initiated before or in the early weeks of pregnancy. METHODS: We will use data from the Study of Mothers and Infants, a retrospective cohort of California 2015-2020 deliveries. We will include pregnancies insured by Medicaid and with a diagnosis of chronic hypertension (n=32,005). RESULTS: Pending. IMPACT: Findings will augment results from randomized controlled trials. Collectively, these studies will inform clinical treatment guidelines for pregnant individuals with chronic hypertension.