Time interval to delivery in asymptomatic twin pregnancies with a short cervix at 23-28 weeks' gestation.

OBJECTIVES

To evaluate the risk and timing of spontaneous preterm birth (PTB) in asymptomatic twin pregnancies with a short cervical length (CL≤25 mm) at 23-28 weeks of gestation.

METHODS

Multicenter retrospective cohort study of asymptomatic twin pregnancies with a short CL between 23 and 28 weeks' gestation within a university health system from 1/2012 to 12/2019. Cases were divided into 4 groups based on CL measurement (≤10 mm, 11-15 mm, 16-20 mm, and 21-25 mm). The primary outcome was time interval from presentation to delivery. Secondary outcomes included delivery within one and two weeks of presentation, and delivery prior to 32, 34, and 37 weeks, respectively.

RESULTS

104 patients were included. The time interval from presentation to delivery was significantly different among the four groups (p<0.001), with the CL≤10 mm group having the shortest time interval to delivery. Regardless of the CL measurement, spontaneous PTB within one and two weeks was extremely uncommon and occurred in only one patient within the study cohort (1/104, 1.0%). The risk of spontaneous PTB was highest in the shortest CL group (CL ≤ 10 mm; 53.8% PTB<32 weeks, 61.5% PTB<34 weeks, 92.3% PTB<37 weeks).

CONCLUSIONS

Asymptomatic twin pregnancies with a CL ≤ 10 mm had the shortest time interval to delivery and thus represent a specifically high risk group for sPTB. Although all patients were at high risk of sPTB, only one delivered within 1 or 2 weeks of presentation.