Preliminary preventive protocol from first trimester of pregnancy to reduce preterm birth rate for dichorionic–diamniotic twins

Objective: The preterm birth rate of twins is reportedly higher than that of single pregnancies. We performed preliminary preventive interventions at our center focused on evaluating the risk of each case before 14 weeks of gestation to reduce the spontaneous preterm birth rate. Materials and methods: The participants included 184 dichorionic–diamniotic twins delivered at our center during the 8 years from 2006. We evaluated each patient regarding high-risk status (at least 1 additional factor as follows: threatened abortion, history of chorioamnionitis, cervicitis, and bacterial vaginosis), based on available evidence; patients deemed high risk gave their informed consent and underwent treatment for cervicitis and cerclage if indicated. We divided the patients into two groups depending on whether the management was initiated before (Group A) or after (Group B) 14 weeks. We further divided Group A into three: Group 1 underwent treatment for cervicitis, Group 2 underwent cervical cerclage in addition to treatment for cervicitis, and Group 3 did not undergo preventive treatment. We retrospectively compared the preterm birth rates of the two groups, and we also compared them between the higher-risk group (Group 1 + 2) and the no additional risk group (Group 3) in Group A. Results: The spontaneous preterm birth rate < 36 weeks was significantly lower in Group A (4/90; 4.4%) than in Group B (18/94; 19.1%) (p = 0.001). However, there were no significant differences between Group 1 + 2 and Group 3 (2/42 vs. 2/46). Focusing on the spontaneous preterm birth rate < 34 weeks, Group A had a lower rate than Group B (2/90; 2.2% vs. 13/94; 13.8%, p = 0.0012). Conclusion: Even though this was a preliminary study, the results are promising, and we propose custom-made management for dichorionic–diamniotic twins: (1) earlier management from before 14 weeks; (2) high-risk selection for cervicitis and a short cervix; and (3) intervention with anti-inflammatory agents and cerclage if indicated.