A common surgical procedure to prevent the cervix opening during pregnancy-thought to reduce the risk of preterm delivery-is called into question by results of a study in this week's issue of THE LANCET.
Cervical cerclage (stitching to keep the cervix closed) has been widely used in the past 50 years to prevent early preterm birth. Kypros Nicolaides from Kings College Hospital, London, UK, and colleagues used ultrasound screening to identify women with a short cervix (assumed to be at a higher risk of premature delivery) and randomized 250 such women to receive either cervical cerclage or no surgery.
Only a small decrease in the proportion of premature births (defined as delivery at or before 33 weeks pregnancy) occurred among women given cervical cerclage (22%) compared with women not given surgery (26%). These proportions are far higher than the UK average for risk of premature delivery (1.5%), highlighting how the ultrasound measurement identified a subgroup of women with small cervices at a high risk of preterm delivery.
Professor Nicolaides comments: "The insertion of a Shirodkar suture in women with a short cervix does not substantially reduce the risk of early preterm delivery. Routine sonographic measurement of cervical length at 22-24 weeks identifies a group at high risk of early preterm birth."