Objective: To evaluate the efficacy of transvaginal cerclage
for twins with cervical dilation or short cervix and to explore the
indicated cervical length for transvaginal cerclage. Design:
Prospective cohort study. Setting: Two tertiary hospitals in
Shanghai, China. Population: A total of 177 twins with
asymptomatic cervical dilation or cervical length ≤15 mm between 16
0/7 and 25 6/7 weeks.
Methods: The logistic regression model and generalized
estimation equation were used to compare the pregnancy outcomes between
no-cerclage group and cerclage group followed by subgroup analysis of
different cervical length. NNT and Kaplan‒Meier curves were used to
estimate the efficacy of cerclage for twins in different groups.
Main Outcome Measures: The primary outcome was gestational age
at delivery and the neonatal survival rate within 3 months after birth.
The secondary outcomes were the gestational latency from diagnosis to
delivery and the risk of preterm birth before 26, 28, 32 and 34 weeks of
gestation. Results: Compared with no-cerclage group, the
gestational age at delivery (32.09±4.50 vs. 28.29±6.20 weeks,
p<0.000) and the gestational latency from diagnosis to
delivery (10.86 [7.14,13.86] vs. 3.00 [0.50,10.29] weeks,
p<0.000) were longer in the cerclage group. The rate of
neonatal survival (86.43% [223/258] vs. 47.92% [46/96],
p<0.000) in the cerclage group was significantly higher. In
the subgroup of twins with cervical dilation or cervical length
<10 mm, twins in the cerclage group had significantly longer
gestational age at delivery (31.33±4.63 vs. 23.44±4.25 weeks,
p<0.001) and gestational latency from diagnosis to delivery
(9.07 [6.29-13.57] vs. 0.43 [0.29-1.71] weeks,
p<0.001). For twins with cervical length of 10-15mm, although
the gestational latency (12 [9.14-13.86] vs. 9.93 [6.29-12.29]
weeks, p=0.037) was significantly longer, there was no difference in
gestational age at delivery (33.05±4.16 vs. 32.40±4.33 weeks, p=0.300)
or neonatal survival rate (87.72% [100/114] vs. 80.77%
[42/52], p=0.238) between the two groups. Conclusion:
Cerclage was associated with improved maternal and neonatal outcomes in
twins with cervical dilation or cervical length <15 mm. More
evidence is needed to confirm the efficacy of transvaginal cerclage for
twins with cervical length of 10 - 15 mm.