High sensitivity and specificity in fetal gender identification in the first trimester, using ultrasound and Noninvasive Prenatal Screening (NIPS) in twin pregnancies, a prospective study.

Introduction: Determination of the fetal gender in the first trimester is important in twin pregnancy cases of familial X-linked genetic syndromes and helps determine chorionicity. We assessed and compared the accuracy of first-trimester ultrasound scans, and cell-free fetal DNA (CfDNA) in determining fetal gender in the first trimester of twin pregnancies.

Methods: Women with twin pregnancies were recruited prospectively during the first trimester.