[Clinical outcomes and influence factors of 435 singleton pregnancies with short cervix]

Objective: To investigate the clinical outcomes of different treatment options on singleton short cervix and its influence factors. Methods: Totally 435 cases of singleton pregnancies who were diagnosed with short cervix (≤25 mm) between 12 to 33⁺⁶ gestational weeks in Peking University First Hospital from January 2018 to December 2018 were enrolled, including 21 cases with cervical length <10 mm, 414 cases with cervical length between 10 to 25 mm. The onset time was <24 gestational weeks in 106 cases, while 104 cases were at 24-29⁺⁶ gestational weeks and 225 cases of ≥30 gestational weeks. Gestational outcomes including delivery before 37 weeks, delivery before 34 weeks, neonatal birth weight (NBW) and adverse neonatal outcome (ANO) were compared among three treatment groups: rest group, progesterone group and cerclage group. Influence factors were also investigated. Results: (1) The incidence of short cervix in pregnancy was 7.07% (435/6 155), while 106 cases were at <24 gestational weeks (1.72%, 106/6 155), 104 cases (1.69%, 104/6 155) at 24-29⁺⁶ gestational weeks and 225 cases (3.66%, 225/6 155) at ≥30 gestational weeks. (2) In the group of cervical length <10 mm, rate of delivery before 37 and 34 weeks were 62% (13/21) and 57% (12/21) respectively. One case of progesterone treatment underwent miscarriage. Compared with rest group (n=8), delivery weeks [28.5 (25.0-40.0) vs 37.0 (28.0-40.0), P=0.020] and NBW [1 245 g (630-3 830 g) vs 2 648 g (1 560-3 830 g), P=0.028] were higher in cerclage group (n=9), while ANO was not statistically different (P>0.05). (3) In the group of cervical length ≥10 mm before 24 gestational weeks, the delivery weeks, incidence of delivery before 34 weeks, adjusted incidence of delivery before 37 weeks, NBW and ANO were not statistically different (P>0.05) among rest group (n=36), progesterone group (n=26) and cerclage group (n=34). In vitro fertilization (OR=11.97, 95%CI: 1.88-76.44, P=0.009), infection (OR=46.03, 95%CI: 5.12-413.58, P=0.001), sludge on sonography (OR=9.87, 95%CI: 1.69-57.60, P=0.011) and history of short cervix (OR=7.24, 95%CI: 1.04-50.24, P=0.045) were independent risk factors of preterm birth. (4) In the group of cervical length ≥10 mm and gestational weeks between 24-29⁺⁶, the delivery weeks, incidence of delivery before 37 weeks, incidence of delivery before 34 weeks, NBW and ANO were not statistically different (P>0.05) among rest group (n=52), progesterone group (n=34) and cerclage group (n=9). Infection was an independent risk factor of preterm birth (OR=56.40, 95%CI: 4.67-680.61, P=0.002). (5) Outcomes of 223 cases were relatively good in the group of cervical length ≥10 mm beyond 30 gestational weeks. The incidence of delivery before 34 weeks was 6.3% (14/223). The delivery weeks, incidence of delivery before 37 and 34 weeks, NBW and ANO were not statistically different (P>0.05) among 3 groups. Infection (OR=10.91, 95%CI: 2.21-53.96, P=0.003) and history of preterm birth (OR=8.63, 95%CI: 1.25-59.65, P=0.029) were independent risk factors of preterm birth. Conclusions: Short cervix is a common complication of pregnancy. Cervical cerclage is related with better outcome for patients with cervical length <10 mm. Neither progesterone nor cervical cerclage improves pregnancy outcome for >10 mm cervical length patients comparing with rest. Infection, sludge, in vitro fertilization, history of short cervix and history of preterm birth are independent risk factors of preterm birth in short cervix pregnancies.