Cervical length at 23 weeks of gestation: the value of Shirodkar suture for the short cervix.

OBJECTIVE To examine the possible benefit of cervical cerclage in women with a very short cervix identified during routine sonographic assessment of cervical length at 23 weeks of gestation. METHODS Transvaginal sonography was used to measure cervical length at 23 weeks of gestation in 2702 women with singleton pregnancies attending for routine antenatal care. In 43 (1.6%) cases the cervical length was < or = 15 mm. The 43 women in this group were referred to their obstetricians for the further management of pregnancy; in 21 cases, the pregnancy was managed expectantly and in 22 a Shirodkar suture was inserted under spinal anesthesia. The two groups were compared in terms of patient characteristics and pregnancy outcome. RESULTS The 22 patients that were treated with cervical cerclage were not significantly different from the 21 given expectant management in ethnic origin, ponderal index, cigarette smoking or past obstetric history. The median cervical length was 10 mm in both groups. In the cervical cerclage group, 21 delivered after 32 weeks and one (5%) had spontaneous onset of labor and delivery before 32 completed weeks; all 22 infants survived. In the expectant management group, 11 (52%) had spontaneous onset of labor and delivery before 32 weeks; 20 infants survived but one baby died in the neonatal period. CONCLUSIONS In women with a cervical length of < or = 15 mm at 23 weeks there is a more than 50% chance of spontaneous delivery at less than 32 weeks. Insertion of a Shirodkar suture in women with a very short cervix may be associated with a ten-fold reduction in risk for such early delivery.