3.3.1 Abortion rate before 28 weeks
Five studies were included for this analysis[9-11,
14, 15]. Due to statistical homogeneity across studies
(P =0.97, I 2=0%), a fixed-effect model
was applied. Results showed that the abortion rate before 28 weeks was
comparable between the cervical pessary group and the cervical cerclage
group (RR =0.57, 95%CI : 0.29 to 1.09, P =0.97)
(Figure 1-2).