WILL (When to Induce Labour to Limit risk in pregnancy hypertension) - a multicentre, randomised controlled trial

In the UK every year, around 42,000 pregnant women develop high blood pressure before 37 weeks, leading to 12,000 women with serious problems, 25,000 emergency Caesarean sections and 240 stillbirths (when the baby dies before or during birth) There is little information to guide doctors and women with high blood pressure when they decide on timing of delivery At present, most of these women who reach 40 weeks (their due date) are offered induction (using hormones to start labour) or Caesarean section by choice For women with high blood pressure, it is possible that delivering the baby before 40 weeks would reduce the chance of health problems for the woman, emergency Caesarean delivery and stillbirth But it is also possible that an earlier delivery would increase the chance of newborn health problems Our trial, called WILL, is testing whether planned delivery at 38 weeks is better than monitoring women and babies until at least 40 weeks The WILL trial will run for 3 years in about 30 UK hospitals We will ask women to take part if they have reached 36 or 37 weeks of pregnancy and have high blood pressure and no other current problems Women who consent will be put into one of two treatment groups, at random One group will have a planned delivery at 38 weeks, by labour induction or elective Caesarean (by choice) The other group will be monitored until at least 40 weeks unless a medical problem develops before that Women continuing to 40 weeks will have the same care as they would usually have in the NHS, and the baby will be delivered before 40 weeks if there are signs of problems for the mother or baby Doctors and midwives will provide normal care before and after birth for all women The main aim of the WILL trial is to see if planned delivery at 38 weeks (compared with monitoring until at least 40 weeks) can reduce problems for mothers without causing problems for babies For example, mothers may develop serious health problems related to high blood pressure or dangerously high blood pressure values Newborns may need neonatal care, meaning the baby is separated from the mother Also, we want to collect information on any potential decrease in emergency Caesareans or stillbirth associated with planned delivery at 38 weeks (compared with monitoring until at least 40 weeks) We need 1080 women to take part to make the study large enough to show whether there are differences between the two groups of women and babies Our team of researchers and care providers is very experienced The safety of women and babies will be carefully monitored We will check that our trial procedures work well in 8 hospitals before extending the trial to all 30 hospitals We anticipate that the trial results will help the growing number of women with high blood pressure, and their midwives and doctors, to make decisions about timing of delivery