Transvaginal sonographic cervical length for the prediction of spontaneous preterm birth in twin pregnancies: a systematic review and metaanalysis

Abstract

Objective To assess the accuracy of transvaginal sonographic cervical length (CL) in predicting spontaneous preterm birth in women with twin pregnancies. Study design Systematic review and metaanalysis of predictive test accuracy. Results Twenty-one studies (16 in asymptomatic women and 5 in symptomatic women) with a total of 3523 women met the inclusion criteria. Among asymptomatic women, a CL ≤20 mm 20-24 weeks’ gestation was the most accurate in predicting preterm birth <32 and <34 weeks’ gestation (pooled sensitivities, specificities, and positive and negative likelihood ratios of 39% and 29%, 96% and 97%, 10.1 and 9.0, and 0.64 and 0.74, respectively). A CL ≤25 mm 20-24 weeks’ gestation had a pooled positive likelihood ratio of 9.6 to predict preterm birth <28 weeks’ gestation. The predictive accuracy of CL for preterm birth was low in symptomatic women. Conclusion Transvaginal sonographic CL 20-24 weeks’ gestation is a good predictor of spontaneous preterm birth in asymptomatic women with twin pregnancies.

Cervical length for the prediction and prevention of preterm birth

“…Among asymptomatic women, a CL ≤20 mm at 20-24 weeks gestation predicts sPTB at <32 and <34 weeks gestation, whereas a CL ≤25 mm predicts preterm birth at <28 weeks gestation [62]. However, the negative predictive value is quite low, so a normal CL is less accurate in predicting the absence of sPTB.…”

Effect of vaginal progesterone in combination with cervical cerclage on improved gestational age and perinatal outcome in twin pregnancy: A prospective randomized study

“…7 Sonographic assessment of cervical length (CL) has long been shown to have comparable efficacy in predicting preterm delivery in twin gestations as in singletons. 8 However, the two mainstays of therapy to reduce the risk of preterm delivery in singletons with short cervix, cervical cerclage and progesterone therapy, have yielded equivocal results in twins. 9 To date, there is no strong evidence that either intervention reduces the risk of preterm delivery in twin gestations complicated by short cervix.…”

The Change in Cervical Length Over Time as a Predictor of Preterm Delivery in Asymptomatic Women With Twin Pregnancies Who Have a Normal Mid-Trimester Cervical Length

“…We assumed that 5% of women with twin pregnancies and a CL > 25 mm at 20-24 weeks gestation have SPTDs at <32 weeks' gestation because previous studies have reported that the rate was 8.5-9.2% (Goldenberg et al, 1996;Guzman et al, 2000), and one half of women with SPTDs at <32 weeks' gestation have a CL > 25 mm at 20-24 weeks' gestation (Conde-Agudelo et al, 2010;Fox et al, 2009;Goldenberg et al, 1996;Yang et al, 2000). Therefore, using an alpha of 0.05 and a power of 0.8, we calculated that a sample size of 189 women would be needed to detect a 15% difference in the change in CL with a standard deviation (SD) of 16% (based on a pilot study).…”

“…A recent meta-analysis indicated that among asymptomatic women with twin pregnancies, a CL ≤ 20 mm at 20-24 weeks' gestation is the most accurate in predicting preterm birth at <32 and <34 weeks' gestation, but a 'normal' CL (defined as a CL > 25 mm) was less accurate in predicting the absence of preterm birth (Conde-Agudelo et al, 2010). Similarly, several studies have reported that approximately one half of women with spontaneous preterm delivery (SPTD) at < 32 weeks have a CL > 25 mm at 20-24 weeks (Conde-Agudelo et al, 2010;Fox et al, 2009;Goldenberg et al, 1996;Yang et al, 2000). At present, however, there is no effective tool to predict the risk of SPTD in the absence of a short CL, despite the fact that by identifying such a high-risk group for SPTD, possible interventions in this cohort can be studied to test their effectiveness.…”