Background: Ambiguity of the external genitalia is usually identified at physical examination after birth. However, genital variations can be detected at the time of routine ultrasound (US) in pregnancy. Guidelines regarding the prenatal diagnostic process is mainly based on expert opinion, rather than clinical research. This makes it unclear to what extent prenatal testing for DSD is useful or practical. This retrospective cohort study was set out to evaluate the prenatal diagnostic process in the Radboudumc DSD centre, and to get insight in the prenatal diagnostic procedures in all Dutch academic centers.

Methods: Data of 18 pregnancies in which variations of the external genitalia were found on US were evaluated. Data regarding prenatal sonographic findings, prenatal diagnostic tests and postnatal diagnosis and gender assignment were collected. A survey was sent to all Dutch academic hospitals with questions about the local policy regarding the prenatal diagnostic process.

Results: In all pregnancies, the first advanced ultrasound was performed at approximately 20 weeks of gestation. In 16(89%) cases, a second ultrasound was performed at a median gestational age of 30 weeks. Prenatal counseling was provided in all cases. Prenatal diagnostic tests were performed in 33% of the cases: NIPT and/or amniocentesis. Seventy-two percent of the fetuses had ambiguous genitalia at the postnatal physical examination. Twenty-eight percent had normal external genitalia. The survey showed that there is no uniform policy regarding prenatal diagnostic tests in Dutch academic hospitals.

Conclusion: Detection of ambiguous genitalia at prenatal ultrasound is not a good predictor of postnatal appearance of ambiguous genitalia. Uncertainty about fetal sex is a stressful situation for parents, and adequate counseling by a specialist of the DSD team is of great importance. There is no consensus on the prenatal diagnostic process in pregnancies with ambiguous genitalia. More research is needed to establish national and international guidelines.