Pregnancy outcomes according to the degree of cervical dilation
We separately analyzed the subgroups with cervical dilation ≥3cm and <3cm. In the subgroup of twin pregnancies with cervical dilation ≥3cm, 24 women were in the case group and 15 were in the controls. There were no significant differences between the groups in sPTB at <32, and <34 weeks; however, there were significant differences in median GA at delivery (30.5 vs 26 weeks, Bate:4.96, 95%CI: 2.69-7.23, p< 0.001), median pregnancy latency (44 vs 22 days, Bate:35.14, 95%CI: 13.97-56.31, p = 0.002), sPTB at <28 weeks (16.7% vs 73.3%, aOR: 0.08, 95% CI: 0.01–0.41, p = 0.003), <30 weeks (33.3% vs 93.3%, aOR: 0.03, 95% CI: 0.01–0.38, p = 0.006) and birth weight (1542.35 vs 802.5 g, Bate:735.41, 95%CI: 355.68-1115.14 p< 0.001)(Table 4 and Table 5). The Kaplan–Meier curves generated for GA at delivery by cervical dilation ≥3cm and log-rank test for pregnancy prolongation showed significant differences between the groups (p<0.001) (Figure 3).
In the subgroup with cervical dilation <3cm, 18 women were in the case group and 27 in the controls. There were significant differences in median GA at delivery (32.5 vs 28 weeks, Bate: 3.24, 95%CI: 1.48-5.01, p= 0.001), median pregnancy latency (59 vs 29 days, Bate:20.54, 95%CI: 6.13-34.95, p = 0.007), sPTB at <28 weeks (0% vs 34.0%, aOR: 0.21, 95% CI: 0.05–0.98, p = 0.047), sPTB at <32 weeks (50.0% vs 81.5%, aOR: 0.17, 95% CI: 0.04–0.75, p= 0.019), and the rates of birth weight >1000g (88.9% vs 55.6%, aOR: 0.12, 95% CI: 0.02–0.74, p = 0.022).(Table 4and Table 5). The Kaplan–Meier curves generated for GA at delivery by cervical dilation <3cm and log-rank test showed a significant difference in prolongation of pregnancy between the groups (p = 0.038) (Figure 4).