Progression of hypertensive disorders of pregnancy during induction of labor in term nulliparous patients

OBJECTIVE: When hypertensive disorders of pregnancy (HDPs) are diagnosed at term, delivery is recommended, because the maternal condition can worsen while the patient remains pregnant.(1,2) However, progression of HDPs can also occur after the decision to deliver, during induction of labor (IOL), and the postpartum period, although these events have not been well characterized. We hypothesized that severe features of preeclampsia can develop during IOL and the postpartum period, even after hospital discharge. Therefore, the aim of this study was to evaluate the prevalence, risk factors, and timing of progression of HDPs after the start of IOL for newly diagnosed HDPs. STUDY DESIGN: This was an observational study of nulliparous patients with singleton term pregnancies who underwent IOL with a Bishop score <= 5 after a new diagnosis of gestational hypertension or preeclampsia without severe features from 2018 to 2020. The primary outcome was subsequent development of severe features of preeclampsia after start of induction (progression of HDP), such as new laboratory abnormalities, symptoms, or severe hypertension by 6 weeks postpartum.(1) Potential sociodemographic and clinical factors predictive of progression of HDPs were evaluated using chi-square tests and multivariate regression adjusted for potentially confounding factors. The timing of progression of HDPs during IOL, the immediate postpartum period (delivery to hospital discharge), or during the delayed postpartum period (discharge to 6 weeks postpartum) was compared. RESULTS: Of 812 patients who underwent IOL for gestational hypertension or preeclampsia without severe features, 16.3% developed progression of HDPs after starting induction. Of 132 patients with progression of HDPs, the majority (52.3%) occurred during labor, although progression also occurred during both the immediate (26.5%) and the delayed (21.2%) postpartum period. There was no difference in the timing of progression between those with gestational hypertension and those with preeclampsia without severe features (P1/4.84). Advanced maternal age (AMA) older than 35 years was associated with the progression of HDPs (22.6% vs 13.5% under age 35 years; P<.01), whereas other factors were not associated with progression (Table). AMA was associated with almost twice the risk for progression (adjusted odds ratio, 1.92; 95% confidence interval, 1.29-2.86) after adjusting for diagnosis, race, insurance, and gestational age. HDP progression was more frequent among those with unplanned cesarean delivery (CD) than among those with vaginal delivery (20.7% vs 13.3%; P<.01) (Table), and this association persisted whether HDP progression occurred before or after the delivery. CONCLUSION: Term nulliparous patients who underwent IOL for gestational hypertension and preeclampsia without severe features had a 16.3% rate of progression to severe features of preeclampsia. HDP progression was more frequent among those with AMA and those who had unplanned CD, regardless of timing of progression before or after delivery. Factors that contributed to the association between progression of HDP and unplanned CD should be investigated further in studies, particularly given the high unplanned CD rate in this study. Finally, we demonstrate that the risk for HDP progression does not end at the decision to deliver, but it also extends into labor and the postpartum period, even after discharge. This is consistent with other short- and long-term health complications from HDP that have been increasingly recognized3-5 and strengthen a call for a paradigm shift in which delivery is no longer considered a cure for HDP.