New management strategy of pregnancies at risk of congenital adrenal hyperplasia using fetal sex determination in maternal serum: French cohort of 258 cases (2002-2011).

Context: Prenatal dexamethasone (DEX) treatment has been proposed since 1984 to prevent genital virilization in girls with congenital adrenal hyperplasia (CAH). DEX is effective in CAH females if initiated before the sixth week of gestation, but its safety in children treated in utero remains controversial regarding cognitive functions.
Objective: To avoid prenatal DEX in males and initiate DEX in due time in CAH females, we proposed in 2002 a protocol for fetal sex determination in the maternal serum (SRY test).
Design and Setting: We conducted a retrospective study of the management of 258 fetuses in the period 2002 through 2011 in pregnancies managed in referent medical centers with an institutional practice.
Patients: A total of 258 fetuses at risk of CAH (134 males and 124 females) were included.
Intervention: DEX was offered after informed consent to pregnant women.
Main Outcome Measure: The sensitivity of an early SRY test was evaluated after data collection.
Results: The SRY test is sensitive from 4 weeks and 5 days of gestation. It avoided prenatal DEX in 68% of males, and this percentage increased over the years. DEX was maintained until prenatal diagnosis in non-CAH females. Virilization was prevented in 12 CAH girls treated at the latest at 6 weeks gestation and minimized in 3 girls treated between 6 and 7 weeks gestation. Maternal tolerance was correct. No fetal malformations were noted in the 154 children treated in utero.
Conclusions: The SRY test is reliable to avoid prenatal DEX in males, but its application must be improved. Prenatal DEX should be maintained to prevent virilization and traumatic surgery in CAH girls after informed consent and information provided to families about the benefit to risk ratio in limiting hyperandrogenism during fetal life. Our large multicentric French cohort has helped to better assess the risks previously reported.