Prenatal diagnosis of sex discordance is a relatively new phenomenon. Prior to cell‐free DNA testing, the diagnosis of a disorder of sexual differentiation was serendipitous, either through identification of ambiguous genitalia at the midtrimester morphology ultrasound or discovery of genotype‐phenotype discordance in cases where preimplantation genetic diagnosis or invasive prenatal testing had occurred. The widespread integration of cfDNA testing into modern antenatal screening has made sex chromosome assessment possible from 10 weeks of gestation, and discordant fetal sex is now more commonly diagnosed prenatally, with a prevalence of approximately 1 in 1500‐2000 pregnancies. Early detection of phenotype‐genotype sex discordance is important as it may indicate an underlying genetic, chromosomal or biochemical condition and it also allows for time‐critical postnatal treatment. The aim of this article is to review cfDNA and ultrasound diagnosis of fetal sex, identify possible causes of phenotype‐genotype discordance and provide a systematic approach for clinicians when counseling and managing couples in this circumstance.

中文翻译：

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NIPT 和超声检查胎儿性别不一致。

性别不一致的产前诊断是一个相对较新的现象。在无细胞 DNA 检测之前，性分化障碍的诊断是偶然的，无论是通过在中期形态学超声中识别出模糊的生殖器，还是在植入前遗传学诊断或侵入性产前检测的情况下发现基因型-表型不一致。cfDNA 检测与现代产前筛查的广泛整合使得从妊娠 10 周开始进行性染色体评估成为可能，现在胎儿性别不一致在产前更常见，其患病率约为 1500-2000 次妊娠中的 1 次。早期发现表型-基因型性别差异很重要，因为它可能表明潜在的遗传、染色体或生化条件，它还允许时间紧迫的产后治疗。本文的目的是回顾胎儿性别的 cfDNA 和超声诊断，确定表型 - 基因型不一致的可能原因，并为临床医生在这种情况下咨询和管理夫妻提供系统方法。