Non-invasive prenatal testing (NIPT) is accurate for fetal sex determination in singleton pregnancies, but its accuracy is not well established in twin pregnancies. Here, we present an accurate sex prediction model to discriminate fetal sex in both dichorionic diamniotic (DCDA) and monochorionic diamniotic/monochorionic monoamniotic (MCDA/MCMA) twin pregnancies. A retrospective analysis was performed using a total of 198 twin pregnancies with documented sex. The prediction was based on a multinomial logistic regression using the normalized frequency of X and Y chromosomes, and fetal fraction estimation. A second-step regression analysis was applied when one or both twins were predicted to be male. The model determines fetal sex with 100% sensitivity and specificity when both twins are female, and with 98% sensitivity and 95% specificity when a male is present. Since sex determination can be clinically important, implementing fetal sex determination in twins will improve overall twin pregnancies management.

无创产前检查（NIPT）对于单胎妊娠中的胎儿性别确定是准确的，但在双胞胎怀孕中其准确度尚不明确。在这里，我们提出了一个准确的性别预测模型，以区分二绒毛膜羊膜炎（DCDA）和单绒毛膜羊膜/单绒毛膜羊膜炎（MCDA / MCMA）双胎妊娠中的胎儿性别。回顾性分析总共使用了198例有性别记录的双胞胎孕妇。该预测基于使用X和Y染色体的归一化频率以及胎儿比例估计的多项逻辑回归。当一个或两个双胞胎被预测为男性时，进行第二步回归分析。当双胞胎都是女性时，该模型以100％的敏感性和特异性确定胎儿性别，当男性出现时，灵敏度为98％，特异性为95％。由于性别确定可能在临床上很重要，因此在双胞胎中实施胎儿性别确定将改善整体双胞胎怀孕管理。