Follow-Up of Asymptomatic High-Risk Patients with Normal Cervical Length to Predict Recurrence of Preterm Birth

Abstract

Background: A midtrimester cervical length (CL) <25 mm is associated with spontaneous preterm birth (sPTB). However, as CL ≥25 mm is not enough to exclude recurrence in high-risk patients, follow-up CL measurement later in pregnancy has been proposed. Objectives: To evaluate whether CL measurement at 26±1 weeks in asymptomatic high-risk patients improves the prediction of sPTB recurrence. Methods: A retrospective cohort of high-risk women because of previous sPTB was analyzed. Patients with a CL ≥25 mm at 20±1 weeks and subsequent CL measurement at 26±1 weeks were included. The exclusion criteria were incomplete follow-up, any treatment before CL assessments, and medically indicated preterm birth. The association and predictive performance of CL at 26±1 weeks for sPTB was studied. Results: Of 131 patients with a CL measurement at 26±1 weeks, 19 and 4.6% presented sPTB before 37 and 34 weeks, respectively. The rate of sPTB before 37 weeks was higher in women with a CL <25 mm (37.5 vs. 16.5%, RR 2.3 [1.07–4.8], p = 0.045), although the detection rate of CL at 26±1 weeks to predict sPTB before 37 weeks was 24% (95% CI 10–46%). The performance did not improve regardless of the selected cutoff. Conclusions: In asymptomatic high-risk patients, CL <25 mm at 26±1 weeks is associated with higher risk of sPTB. However, the prediction of recurrence by CL was low and did not improve, regardless of the selected cutoff.

Universal cervical length screening for preterm birth is not useful after 24 weeks of gestation

“…The use of a 25‐mm CL threshold, the same used for universal screening in the 18–24 week window, only identifies a small proportion of women who will deliver preterm. The screen‐positive rate for CL ≤ 25 mm in our cohort was 2.5% at 24 +0 –27 +6 weeks and 6.1 at 28 +0 –32 +0 weeks, which is similar to that reported on previous studies in asymptomatic singleton pregnancies that were screened at approximately 24–30 weeks of gestation 14,16–19 …”

“…The screen-positive rate for CL ≤ 25 mm in our cohort was 2.5% at 24 +0 -27 +6 weeks and 6.1 at 28 +0 -32 +0 weeks, which is similar to that reported on previous studies in asymptomatic singleton pregnancies that were screened at approximately 24-30 weeks of gestation. 14,[16][17][18][19] The prevalence of sPTB in our population was low (1.9%), and is lower than those reported on previous studies (range 4.3%-12.5%). 5,16,17 The difference may be explained by the criteria used…”

“…The screen‐positive rate for CL ≤ 25 mm in our cohort was 2.5% at 24 +0 –27 +6 weeks and 6.1 at 28 +0 –32 +0 weeks, which is similar to that reported on previous studies in asymptomatic singleton pregnancies that were screened at approximately 24–30 weeks of gestation. 14 , 16 , 17 , 18 , 19 …”

Assessment of utero‐cervical angle and cervical length as predictors for threatened preterm delivery in singleton pregnancies

“…Performance of UCA and CL measurements with relation to preterm delivery and the time interval until delivery in patients with contractions was another issue addressed in our study and showed significance for gestational age, CL, and UCA. Recent studies confirmed the relationship between CL and duration of pregnancy for threatened abortions and recurrence in asymptomatic pregnancies 24,25 . Our study showed a correlation between CL and UCA with the duration of pregnancy for TPL; specifically, the shorter CL and the wider the UCA, the greater the risk for preterm delivery.…”