Clinical Utility of Increased Nuchal Translucency at 11–13 Weeks of Gestation in Twin Pregnancies Based on the Chorionicity

Siwon Lee,You Jung Han,Moon Young Kim,Jin Hoon Chung,Hye Yeon Boo,Hyun-Mi Lee

doi:10.3390/jcm10030433

Abstract

To assess clinical implications of increased nuchal translucency (INT) in twin pregnancies based on the chorionicity. This was a retrospective review of the twin pregnancies who underwent first trimester ultrasound with nuchal translucency (NT) measurement at 11–13 weeks of gestation from January 2006 to December 2014. Data were collected using the OB database and the chart review. Pregnancy outcomes, including gestational weeks at the delivery, abnormal fetal karyotypes, fetal structural anomalies, and twin-specific complications, were analyzed. A total of 1622 twin pregnancies with INT ≥ 95th percentile in one or both fetuses were identified. In all twin pregnancies with INT, abnormal fetal karyotypes were identified in 17 (8.6%) patients (odds ratio = 13.28, CI = 5.990–29.447, p = 0.000) and twin-specific complications were identified in 23 (11.6%) patients (odds ratio = 2.398, CI = 1.463–3.928, p = 0.001) compared to those with normal NT. Among the INT group, when the groups were subdivided into monochorionic (MC) and dichorionic (DC) pregnancies, 14.8% and 29.6% of the MC pregnancies had structural anomalies in one or both fetuses (odds ratio = 5.774, 95% CI = 1.445–23.071, p = 0.01) and twin-specific complications (odds ratio = 4.379, 95% CI = 1.641–11.684, p = 0.03), respectively, compared to DC pregnancies with 2.9% for structural anomalies and 8.8% for twin-specific complications. The prevalence of abnormal fetal karyotypes was not statistically different in patients with INT when compared between MC and DC pregnancies (p = 0.329). INT was associated with a higher rate of twin-specific complications and fetal structural anomalies in MC twin pregnancies rather than abnormal fetal karyotype. Therefore, NT measurement in MC twin pregnancies can be a useful tool for predicting adverse pregnancy outcomes. Appropriate counseling and surveillance based on the chorionicity are imperative in the prenatal care of twin pregnancies.

Highlights

Several researchers have reported a comparison of increased nuchal translucency (INT) versus normal nuchal translucency (NT) in either DC or MC twins [20,21], those studies did not focus on the pregnancy outcomes in relation to INT in twin pregnancies based on the chorionicity
Our data suggest that INT in the first trimester ultrasound in twin pregnancy should be considered in different aspects based on the chorionicity
Our study emphasizes that INT in DC twin pregnancies correlates with the increased incidence of abnormal fetal karyotype, which is similar to that of singleton pregnancies based on individual NT measurement

Summary

Introduction

The incidence of multiple gestations is rising, due to an increased rate of assisted reproductive techniques (ART) and advanced maternal age [1]. The risk of chromosomal abnormalities is increasing because of advanced maternal age as a result of delayed childbearing [2]. Options for the aneuploidy screening in twin pregnancies are similar to those performed in singleton pregnancies, including nuchal translucency measurement, maternal serum screening test, and cell-free DNA (cfDNA) test. Interpretation of the maternal serum screening test is challenging in multiple pregnancies, and the detection rate (DR)

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