Randomized Study of Pessary vs Standard Management in Women With Increased Chance of Premature Birth

Prematurity is responsible for more than half of all neonatal deaths and whilst advances in neonatal care have dramatically improved survival of extremely premature infants, there remains a significant risk of handicap and disability in survivors and an associated social and economic burden.

In singleton pregnancies the rate of spontaneous premature birth before 34 weeks is about 1% and the risk of spontaneous early delivery is inversely related to cervical length. The group with cervix of 1-15 mm accounted for 28% of all spontaneous deliveries before 34 weeks and those with cervix of 16-25 mm accounted for 21%. The rate of spontaneous premature birth before 34 weeks is about 13% in twin pregnancies.

Potential methods for the prevention of preterm delivery include bed rest, cervical cerclage and prophylactic administration of progesterone. The prophylactic administration of progesterone beginning in mid-gestation to women who previously had a premature birth and in those with a short cervix has been shown to reduce the rate of spontaneous preterm birth before 34 weeks. On the other hand, randomized studies reported that, in twin pregnancies, bed rest was associated with a significant increase, rather than decrease, in the rate of early preterm delivery.

There is some evidence that the rate of premature birth can be dramatically reduced by the insertion of a vaginal pessary (cerclage pessary, CE0482, MED/CERT ISO 9003 / EN 46003).

This will be a multicenter trial in the UK and other countries. During routine ultrasound scan at 20-24 weeks of gestation for examination of fetal anatomy and growth, all women with twin pregnancy or with singleton pregnancy found to have a cervix of <25 mm in length and where the fetuses are found to be alive with no major abnormalities, severe twin to twin transfusion syndrome or severe fetal growth restriction in one of the fetuses (in the case of twin pregnancy), will be invited to participate in a randomized trial of standard management vs vaginal insertion of a cerclage pessary. For singleton pregnancy, in both arms the patients with cervical length <15 mm will be given prophylactic progesterone (200 mg vaginal capsule per night up to 34 weeks). Randomization and insertion of the pessary (in those allocated to this group) will be carried out within 5 days after the 20-24 weeks scan.