Timing of Hypertensive Disorders of Pregnancy in Nulliparous Individuals and Risk of Incident Chronic Hypertension 2–7 Years Postpartum

OBJECTIVE: – We sought to evaluate the association between the timing of new-onset hypertensive disorders of pregnancy (HDP) development (ie, antepartum, intrapartum, or postpartum) and the risk of incident hypertension 2–7 years after delivery in nuMoM2b (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be) and nuMoM2b-HHS (the nuMoM2b Heart Health Study).METHODS: – This is a secondary analysis of a multisite prospective observational cohort study conducted at eight clinical sites that enrolled nulliparous individuals with singleton pregnancies in their first trimester who were followed during pregnancy and subsequently underwent a cardiovascular screening visit 2–7 years after delivery. For this analysis, we excluded individuals with prepregnancy chronic hypertension in their nuMoM2b pregnancy. We compared rates of stage 1 hypertension (blood pressure 130/80 mm Hg or higher or use of antihypertensive medications) at the 2–7 year postpartum study visit based on the timing of the onset of HDP (categorized as antepartum, intrapartum, postpartum) with no HDP (referent). Multivariable logistic regression models adjusted for baseline covariates (age, insurance, tobacco use, diabetes, and early pregnancy body mass index [BMI]) were used to generate adjusted odds ratios (aOR) and 95% CIs. Interaction analysis was performed to evaluate effect modification by the presence of severe features of HDP. P<.05 was considered statistically significant.RESULTS: – Of 4, 342 individuals included in this analysis (mean age 27.0 years [SD 5.6 years]), 23.2%% (n=1, 007) had new-onset HDP. Among those with HDP, 53.6% (n=540) were diagnosed antepartum, 42.4% (n=427) were diagnosed intrapartum, and 4.0% (n=40) were diagnosed postpartum. At a mean follow-up of 3.2±0.9 years after delivery, the frequency of incident hypertension was elevated regardless of whether HDP occurred antepartum (37.6%, n=203), intrapartum (26.0%, n=111), or postpartum (40.0%, n=16) (compared with no HDP [16.5%, n=550]). After adjustment for maternal age, insurance type, tobacco use, prepregnancy diabetes, and early pregnancy BMI, the risk of chronic hypertension remained elevated regardless of when HDP was diagnosed, although the risk was higher when it developed antepartum (aOR 2.40, 95% CI, 1.95–2.95) or postpartum (aOR 2.90, 95% CI, 1.49–5.64) compared with when it developed intrapartum (aOR 1.55, 95% CI, 1.21–1.97; referent no HDP, P<.01 for all).CONCLUSION: – New-onset HDP, regardless of whether it is diagnosed antepartum, intrapartum, or postpartum, is associated with an increased risk of incident hypertension 2–7 years after delivery, compared with individuals without HDP during their first birth. Greater awareness of cardiovascular disease risk after HDP—even when HDP is diagnosed during labor or postpartum—is needed to appropriately risk stratify and help prevent hypertension after delivery.CLINICAL TRIAL REGISTRATION: – ClinicalTrials.gov, NCT02231398.