Hypertensive disorders of pregnancy (HDP), such as gestational hypertension and pre‐eclampsia; complicate about 10% of gestations and are major contributors to maternal; and neonatal morbidity and mortality. Despite extensive research efforts, the best treatment for HDP currently available is delivery of the placenta.

The Hypertension and Preeclampsia Intervention Trial At near Term‐I (HYPITAT‐I) randomized clinical trial; carried out from October 2005 to March 2008, showed that; compared to expectant management, induction of labor in women with gestational hypertension or mild pre‐eclampsia at term is associated with improved maternal outcome; without affecting Cesarean‐section rate and without compromising neonatal outcome or maternal quality of life.

Women with gestational hypertension

They 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, they 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. 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; and perinatal death decreased from 0.49% to 0.27%, 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 in the reference group; however, the relative increase in the HDP group (13.1 % points) was significantly greater.

Maternal and perinatal deaths

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. 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

This study has shown an improvement in the quality of obstetric healthcare in The Netherlands between 2000 and 2014 for term pregnancies complicated by HDP. After HYPITAT‐I, induction of labor increased in this group of pregnant women, which might have contributed to the observed reductions in maternal morbidity and mortality and perinatal mortality.