Longitudinal changes in canal length at 16–35 weeks in normal twin pregnancies and twin pregnancies with preterm labor and delivery

Abstract

A short canal length at 16-19 weeks followed by rapid canal length shortening in the second trimester are specific characteristics in preterm labor and delivery of twin pregnancies. Sequential measurements of canal length in the second trimester starting at < 20 weeks may be a suitable parameter to predict preterm labor and delivery in twin pregnancies.

Prediction of Preterm Birth in Multiple Pregnancies: Development of a Multivariable Model Including Cervical Length Measurement at 16 to 21 Weeks’ Gestation

“…Here, the baseline hazard was 0.881 for very preterm birth and 0.442 for preterm birth, βX equals 0.187*lower education + −0.504*multiparous without previous preterm birth + 0.432*multiparous with previous preterm birth + 0.225*smoking + 1.41*triplet + 0.439*monochorionic + 0.631*CL < 30 mm + 0.206*randomization to progesterone, and βX = 0.192. When the above is applied to a non-smoking, highly educated, multiparous woman with a dichorionic twin pregnancy who had no previous preterm birth, no progesterone treatment, and a CL < 30 mm we find a risk of 1 -0.442^exp (−0.504 + 0.631 -0.192) = 54% of Since women with a short cervix early in pregnancy have a higher chance of spontaneous preterm birth than those with the same length later in pregnancy, 5,19,22,23 19 and Fox (n = 309) showed a mean CL of 42 mm at 16 weeks and 40 mm at 20 weeks (90% CI 34 to 50 mm and 31 to 49 mm, respectively). 9 In our study, the mean CL of women who delivered at term was 45 mm at 16 to 21 weeks (90% CI 30 to 60 mm), and did not change according to the gestational age at which the CL was measured.…”

Cervical Length Measurement for the Prediction of Preterm Birth in Symptomatic Women with a Twin Pregnancy: A Systematic Review and Meta-Analysis

“…Yoshizato et al [23] investigated women with a twin pregnancy and regular uterine contractions or cervical ripening. Women with a potential medical background leading to PTB, such as cone biopsy, uterine anomalies, maternal complication like hypertension or diabetes, history of miscarriage or PTB between 16 and 32 weeks, vaginal bleeding, or twin-to-twin syndrome were excluded.…”

Predictive value of cervical length in women with twin pregnancy presenting with threatened preterm labor

“…The association between CL and the risk of PTD in asymptomatic women with a twin pregnancy has been widely reported in the past. However, few studies have investigated the predictive role of CL in symptomatic women presenting with threatened PTL. In a recently published meta‐analysis, Liem et al included five studies with a total of 226 women with twin pregnancies presenting with PTL.…”

“…One of the most widely investigated tools for the prediction of PTD in women with a singleton pregnancy and threatened PTL is sonographic measurement of cervical length (CL). However, while there is a significant amount of evidence regarding the role of CL in asymptomatic women with twin pregnancies, there is only limited information regarding the performance of CL in women with twin pregnancies who present with threatened PTL.…”