What is predictive of preterm delivery in the first trimester: isthmus or cervical length?

Abstract

Measurement of the cervico-isthmic complex enables detection of a number of patients who will go on to deliver before term. Further studies are necessary to confirm that isthmic length and not cervical length is predictive of preterm delivery.

Prediction of Preterm Delivery by Late Cervical Length Measurement after 24 Weeks

“…There is recent evidence that first-trimester CL is also predictive of preterm delivery, although other studies do not support these findings [13,14,15,16,17]. In addition, first-trimester CL may predict about 60% of the pregnancies that will have a second-trimester miscarriage [18].…”

“…In addition, first-trimester CL may predict about 60% of the pregnancies that will have a second-trimester miscarriage [18]. Still, mid-trimester (20-24 weeks) CL remains a better screening tool for prediction of preterm delivery compared to the measurement at 11-14 weeks [1,2,3,4,13,14,15,16,17]. Mid-trimester CL is particularly efficient in the prediction of very early (<28 weeks) birth [2,4].…”

Cervical length in late second and third trimesters: a mixture model for predicting delivery

“…Recently, CL measured in the first trimester at 11–14 weeks' gestation has been evaluated and shown by some research groups to be predictive of preterm delivery, albeit with lower sensitivity. Furthermore, first‐trimester CL appears to be prognostic of a short cervix in the second trimester.…”

Transvaginal sonographic cervical length in first and second trimesters in a low‐risk population: a prospective study

“…Combined first‐trimester screening (cFTS) provides a unique opportunity to assess the effectiveness of first‐trimester CL as a screening tool for PTD, although there is conflicting evidence regarding its predictive value. However, recent single‐center studies focusing on endocervical length suggest an association between first‐trimester CL and PTD.…”