Short cervical lengths initially detected in mid-trimester and early in the third trimester in asymptomatic twin gestations: Association with histologic chorioamnionitis and preterm birth.

Jeong Woo Park,Kyo Hoon Park,Eun Young Jung,Soo-Hyun Cho,Ji Ae Jang,Ha-Na Yoo,Brenda A Wilson

doi:10.1371/journal.pone.0175455

Jeong Woo Park, Kyo Hoon Park + Show 5 more

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https://doi.org/10.1371/journal.pone.0175455

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Abstract

ObjectiveTo determine whether short cervical lengths (≤20 mm) that were initially detected in mid-trimester and early in the third trimester are independently associated with increased risks of subsequent histologic chorioamnionitis and spontaneous preterm birth (SPTB, defined as a delivery before 34 weeks) in asymptomatic women with twin pregnancies.Material and methodsThis is a prospective study including 292 consecutive asymptomatic women with twin gestations. Cervical length measurements were carried out at 20 to 24 weeks’ gestation and at 28 to 32 weeks’ gestation. Both placentas of each twin pair were examined histologically after delivery. The generalized estimation equations models and logistic regression analysis were used for statistical analyses.ResultsMultivariable generalized estimation equations analysis revealed that short cervical length at mid-trimester was independently associated with an increased risk for subsequent histologic chorioamnionitis, whereas short cervical length initially detected early in the third trimester was not. By using the likelihood of SPTB as an outcome variable, multivariable logistic regression analysis indicated that short mid-trimester cervical length and histologic chorioamnionitis were independently associated with a greater risk for SPTB. Similarly, based on the multivariable analysis, a short third trimester cervical length was independently and significantly associated with a greater risk for SPTB.ConclusionsIn asymptomatic women with twin pregnancies, a short mid-trimester cervical length is independently associated with an increased risk of both subsequent histologic chorioamnionitis and SPTB, whereas a short cervical length initially detected early in the third trimester is independently associated with preterm delivery, but not subsequent histologic chorioamnionitis.

Highlights

Twin pregnancies have increased during the last decade, reaching 33.2 per 1000 births in 2009, and have a six to ten times increased risk of preterm birth compared with singleton pregnancies [1]
Multivariable generalized estimation equations analysis revealed that short cervical length at mid-trimester was independently associated with an increased risk for subsequent histologic chorioamnionitis, whereas short cervical length initially detected early in the third trimester was not
In asymptomatic women with twin pregnancies, a short mid-trimester cervical length is independently associated with an increased risk of both subsequent histologic chorioamnionitis and spontaneous preterm birth (SPTB), whereas a short cervical length initially detected early in the third trimester is independently associated with preterm delivery, but not subsequent histologic chorioamnionitis

Summary

Introduction

Twin pregnancies have increased during the last decade, reaching 33.2 per 1000 births in 2009, and have a six to ten times increased risk of preterm birth compared with singleton pregnancies [1]. A short cervical length at mid-trimester is associated with an increased risk of intra-uterine infection/ inflammation [5,6,7, 10]. In contrast to a short cervical length at mid-trimester, the effect of a short cervical length initially detected early in the third trimester on intra-uterine infection/inflammation and preterm delivery is unknown, despite the fact that cervical shortening in the third trimester is a relatively common finding in twin gestations [14]. The purpose of the study was to determine whether short cervical lengths that were initially detected in the mid-trimester and early in the third trimester are independently associated with increased risks of subsequent histologic chorioamnionitis and spontaneous preterm birth (SPTB) in asymptomatic women with twin pregnancies

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Conclusion