Objective: To investigate the association between mid-trimester residual cervical length (CL) and the risk of preterm birth in pregnancies after abdominal radical trachelectomy (RT).
Design: Retrospective cohort study.
Setting: University hospital.
Population: A total of 33 deliveries after 22 weeks' gestation in 30 women who underwent abdominal RT including prophylactic cervical cerclage and perinatal care between January 2002 and May 2016.
Methods: The association between mid-trimester residual CL (the distance between the cerclage and the external cervical os) and gestational age at delivery was investigated. Receiver-operating characteristics (ROC) curve analysis was performed to estimate the optimal cut-off values of the mid-trimester residual CL for the prediction of preterm birth.
Main outcome measures: Preterm birth before 34 weeks' gestation.
Results: Mid-trimester residual CL showed a significant correlation with gestational age at delivery (r = 0.36, P < 0.05). There was a significant difference in residual CL between women who did and those who did not give birth before 34 weeks (P < 0.05). Mid-trimester residual CL < 13 mm was a good predictor of birth before 34 weeks, with a sensitivity of 67%, specificity of 75%, positive predictive value of 55% and negative predictive value of 86% (area under ROC curve, 0.75).
Conclusions: Mid-trimester residual CL is significantly correlated with gestational age at delivery. Residual CL assessment could be used to reassure physicians and women that there is only a small chance of preterm birth in pregnancies after abdominal RT.
Tweetable abstract: Mid-trimester residual cervical length is a good predictor of preterm birth after radical trachelectomy.
Keywords: Abdominal radical trachelectomy; cervix; length; preterm birth; transvaginal.
© 2017 Royal College of Obstetricians and Gynaecologists.