Hypertension and Pre-eclapmsia Intervention Trial At Term
Go to the HYPITAT page
May 9 2008: First results
The first results of the Hypitat study indicate that induction of labor has multiple advantages over an expectant management in term pregnancies with pregnancy-induced hypertension or mild preeclampsia. The Hypitat symposium presentations can be found on the Hypitat website.
10% to 15% of all pregnancies are complicated by hypertensive disorders, i.e. pregnancy induced hypertension or pre-eclampsia (19.000 women per year in The Netherlands). The large majority of these cases occur at term. There is no causal treatment but termination of pregnancy. In case ofpre-term pregnancies complicated by hypertension, conservative management is advocated to as long as the risks for the mother are acceptable. However, there is no consensus whatsoever on the question in such cases at term. Induction of labour might prevent maternal and neonatal complications, but it isalso thought to increase the instrumental delivery rate. Nothing is known about the impact of both policies on the psychological well-being of the mother, as well as the costs of both. In The Netherlands in 2002, labour was induced in 9.000 women with pregnancy induced hypertension or pre-eclampsia, whereas labour started spontaneously in 10.000 women.
Multicentre prospective randomised controlled trial.
Women with a singleton pregnancy and pregnancy-induced hypertension or pre-eclampsia with a gestational age between 36 0/7 weeks and 41 0/7weeks.
Induction of labour, if necessary preceded by artificial cervical ripening versus expectant monitoring.
The primary outcome measure will be severe maternal morbidity, which can be complicated by maternal mortality in rare cases. Severe maternal morbidity will be defined as diastolic BP >= 110 mmHg, systolic BP >= 170 mmHg, major postpartum hemorrhage (blood loss > 1000 ml within 24 hours after delivery), eclampsia, HELLP syndrome, pulmonary edema, trombo-embolic disease and/or abruptio placentae.
Secondary outcomes will be neonatal mortality or neonatal morbidity, caesarean section rate, instrumental vaginal delivery rate, maternal quality of life and quality of recovery and costs. Adverse neonatal outcome will be defined as a 5-minute Apgar score below 7, an umbilical artery pH below 7.05 or admission to the neonatal intensive care.
The analysis will be by intention to treat. The aim of induction of labour is to reduce the rate of severe complications of hypertensive disease. In women with a singleton pregnancy in cephalic presentation at term (>36 weeks), the prevalence of such complications in 2003 and 2004 was 12%. To our opinion, the disadvantages of induction of labour outweigh the advantages when the complication rate is reduced to 6%. In order to detect such a difference, we will need two groups of 360 patients (two-sided test, alpha .05; beta .80). In anticipation of equivalence in maternal and neonatal outcome and quality of life the economic analysis will be a cost-minimisation analysis. For each of the two strategies, will calculate costs of perinatal care for mother and child.
Total study time 36 months. Preparation three months, recruitment 27 months, analysis and report six months. Both data analysis and economic analysis will be performed within thecontext of a consortium of perinatal centres that are already collaborating in the Zon-MW fundedDIGITAT-study (Zon-MW 945-04-558).
Dr. M.G. Van Pampus, gynaecologist, UMCG Groningen
Dr. B.W. Mol, gynaecologist, MMC Veldhoven
Health Technology Assessment
Prof. Dr. G.J. Bonsel, AMC Amsterdam
Dr. S. Le Cessie, epidemiologist LUMC
Dr. E. Birnie, health economist, AMC
Drs. D. Bijlenga, AMC
Drs. C.M. Koopmans, UMCG
Drs. S.M.C.Vijgen, AMC
ZonMw - www.zonmw.nl