Impact of Hypertension and Preeclampsia Intervention Trial At Near Term-I (HYPITAT-I) on obstetric management and outcome in The Netherlands

Objective: The Hypertension and Preeclampsia Intervention Trial At near Term-I (HYPITAT-I) randomized controlled trial showed that, in women with gestational hypertension or mild pre-eclampsia at term, induction of labor, compared with expectant management, was associated with improved maternal outcome without compromising neonatal outcome. The aim of the current study was to evaluate the impact of these findings on obstetric management and maternal and perinatal outcomes in The Netherlands. Methods: We retrieved data for the period 2000–2014 from the Dutch National Perinatal Registry, including 143 749 women with gestational hypertension or pre-eclampsia and a singleton fetus in cephalic presentation, delivered between 36 + 0 and 40 + 6 weeks of gestation (hypertensive disorder of pregnancy (HDP) group). Pregnant women without HDP were used as the reference group (n = 1 649 510). The HYPITAT-I trial was conducted between 2005 and 2008. To study the impact of HYPITAT-I, we compared rate of induction of labor, mode of delivery and maternal and perinatal outcomes in the periods before (2000–2005) and after (2008–2014) the trial. We also differentiated between hospitals that participated in HYPITAT-I and those that did not. Results: In the HDP group, the rate of induction of labor increased from 51.1% before the HYPITAT-I trial to 64.2% after it (relative risk (RR), 1.26; 95% CI, 1.24–1.27). Maternal mortality decreased from 0.022% before the trial to 0.004% after it (RR, 0.20; 95% CI, 0.06–0.70) and perinatal death decreased from 0.49% to 0.27% (RR, 0.54; 95% CI, 0.45–0.65), which was attributable mostly to a decrease in fetal death. Both the increase in induction rate and the reduction in hypertensive complications were more pronounced in hospitals that participated in the HYPITAT-I trial than in those that did not. Following HYPITAT-I, the rate of induction of labor also increased (by 4.6 percentage points) in the reference group; however, the relative increase in the HDP group (13.1 percentage points) was significantly greater (P < 0.001 for the interaction). The reduction in maternal and perinatal deaths did not differ significantly between the HDP and reference groups. There was a decreased incidence of placental abruption in both HDP and reference groups, which was significantly greater in the HDP than in the reference group (P < 0.001 for the interaction). There was also an increased incidence of emergency Cesarean section in both HDP and reference groups; however, this change was significantly greater in the reference than in the HDP group (P < 0.001 for the interaction). Conclusion: Following the HYPITAT-I trial, there was a higher rate of induction of labor and improved obstetric outcome in term pregnancies complicated by HDP in The Netherlands.