Factor Associated with the Successful Prevention of Preterm Birth in Singleton Pregnant Women with a History of Spontaneous Preterm Birth or Incompetent Cervix

Abstract

Background and Objective:    To study the factors associated with the successful prevention of preterm birth in singleton pregnant women with a history of spontaneous preterm birth or incompetent cervix.

Materials and methods: This prognostic research, retrospective cohort design recruited singleton pregnant women with a history of spontaneous preterm birth or incompetent cervix, who had antenatal care at Maharat Nakhon Ratchasima Hospital and delivered between October 2017 and September 2020. They received 17-alpha-hydroxy-progesterone caproate; (17-OHPC) 250 mg intramuscular injection weekly from 16 – 36 weeks gestation and measured cervical length biweekly from 16 – 24 weeks gestation. They received a cervical cerclage immediately if short cervix (less than 25 mm). By the way, the incompetent cervix group could receive a cervical cerclage immediately at 12 – 14 weeks gestation without the measurement of cervical length and continued 17-OHPC 250 mg intramuscular injection weekly from 16 – 36 weeks gestation. Age, body mass index (BMI), progestogen administration, transvaginal ultrasound cervical length (TVU-CL), cervical cerclage, and delivery status were recorded. Pregnant women with severe fetal anomalies, unknown delivery status, stillbirth, and indicated preterm birth were excluded from this study.

Results: We recruited 120 cases in the study, but 6 cases were excluded. 114 cases were remaining in this study. 78 cases had term delivery (68.4%). There was no difference in age, BMI, cervical length,  and progestogen administration between the term and preterm delivery groups. When analyzed in the cervical cerclage group (18 cases): 12 cases had a term delivery (66.7%). They received a cervical cerclage at 17.4 ± 4.1 weeks gestation: the incompetent cervix group was done at 15.2 ± 3.2 weeks gestation and the short cervix group was done at 20.5 ± 3.1 weeks gestation. There was a statistical significance that the term delivery group received a cervical cerclage faster than the preterm group. (p=0.022)

Conclusion: There was no difference in age, BMI, and previous pregnancy history between the term and preterm delivery groups. However, we found a trend that may increase preterm birth such as the short cervix at the first time, delayed cervical cerclage, or previous preterm birth ≥ 2 times. Nevertheless, cervical cerclage before 16 weeks gestation without waiting to measure cervical length may increase the prevention of preterm birth.