Prehypertension prior to or during early pregnancy is associated with increased risk for hypertensive disorders in pregnancy and gestational diabetes

OBJECTIVE:To examine whether and to what extent pre/early-pregnancy blood pressure (BP) in the prehypertensive range contributes to the development of hypertensive disorders in pregnancy and gestational diabetes mellitus (GDM). METHODS:The cohort consisted of women who had their prenatal care and delivered a live singleton neonate at the Kaiser Permanente Bellflower Medical Center during 2005–2010. Women with prepregnancy hypertension (HTN) were excluded from the analysis. Among the remaining women, pre/early-pregnancy prehypertension (preHTN) was defined as two consecutive elevated BPs (SBP ≥ 120 or DBP ≥ 80) at separate ambulatory visits in the period from 1 year prior to pregnancy through the first trimester. Hypertensive disorders of pregnancy, including pre-eclampsia/eclampsia (PE/E), were identified by ICD-9 diagnoses. Mid-pregnancy 75-g oral glucose tolerance tests were used to identify GDM. Multivariable logistic and robust Poisson regression was used to test the association between preHTN and each outcome, adjusted for potential confounders. RESULTS:Among 7802 women with at least two BP measures prior to or early in pregnancy, 2156 (27.6%) had preHTN. Overall, 653 (8.4%) developed a hypertensive disorder of pregnancy, 373 (4.8%) had PE/E, and 1877 (24.1%) developed GDM. After covariate adjustment, women with preHTN were 2.65 [95% confidence interval (CI) 2.22–3.16], 2.17 (95% CI 1.72–2.73), and 1.20 (95% CI 1.09–1.33) times as likely to develop any hypertensive disorder, PE/E, and GDM, respectively, compared to normotensive women. CONCLUSION:Prospective studies aimed at evaluating whether women with preHTN detected prior to or early in pregnancy may benefit from more intensive screening and/or interventions to prevent hypertensive disorders in pregnancy and GDM are needed.