Close to half of twin gestations end before term, and more than 20% deliver before 34 weeks’ gestation. The risk of preterm delivery (PTD) reportedly increases as cervical length (CL) decreases. Reports that PTD is more frequent when a cerclage is placed for cervical shortening prompts the question of whether routinely measuring CL alters the outcome of twin pregnancies. This retrospective review compared outcomes in twin gestations with, and those without a CL. Of 262 women enrolled in the study, 184 had CLs and 78 did not. Those with CLs were likelier to be older and they presented significantly earlier for their first ultrasound study. Similar numbers of women in the two groups had a history of PTD or two or more spontaneous abortions. A median of 4 CL measurements was made.
No differences between the CL and no-CL groups were found with respect to gestational age at delivery, preterm labor, or PTD before 28, 34, or 37 weeks’ gestation. Rates of spontaneous abortion before 24 weeks also were similar in the two groups, as were cervical risk factors. There were no significant differences in antepartum hospital admission, cerclage placement, or use of tocolytic agents. Women in the CL group were admitted for an average of 34.5 days, compared to 31.3 days for the no-CL group, a significant difference. Antepartum length of stay, however, did not correlate with the number of CLs. Neonatal outcomes including birth weight and admission to neonatal intensive care were comparable in the two groups. Logistic regression analysis, controlled for potential confounding factors, showed that antepartum admission was an independent risk factor for birth before 34 weeks’ gestation. The odds ratio was 1.06, with a 95% confidence interval of 1.00-1.12.
Routine measurements of CL did not substantially either maternal or neonatal outcomes in this study of twin gestations.