Context: Limited data are available on the exact incidence of disorders of sex development (DSD) with genital ambiguity at birth.
Objective: To determine frequency of ambiguous genitalia in newborns.
Design: Prospective multicenter study.
Setting: Three tertiary care hospitals.
Patients or other participants: All 14,177 babies born during the study period were included.
Main outcome measures: All newborns were examined at birth; data on weeks of gestation, birth weight, and length were collected. A structured questionnaire was used for data collection. Quigley and Prader scales were used for phenotypic grading. Clinical and genetic investigations were performed.
Results: Eighteen babies with ambiguous genitalia were found among 14,177 newborns (1.3/1000). Fifteen newborns had 46,XY DSD, one had 46,XX congenital adrenal hyperplasia, and one had 45,X/46,XY mixed gonadal dysgenesis. Karyotype analysis was not done in one baby who died in the neonatal period. The ratio of prematurity was higher in the DSD group (44% vs 11%; P < 0.001) and the ratio of small for gestational age was also higher in the DSD group (22% vs 5%; P = 0.007). Eight babies with DSD had mothers who had additional medical conditions, such as preeclampsia, depression, insulin resistance, and gestational diabetes mellitus.
Conclusion: The frequency of ambiguous genitalia was higher than in previous studies, but, as with any experiment, the finding should be met with caution because this study was conducted in tertiary care hospitals. In addition, lower birth weight in the DSD group supports the hypothesis that early placental dysfunction might be important in the etiology of male genital anomalies.
Keywords: ambiguous genitalia; androgen insensitivity; birth defects; disorders of sex development; gonadal dysgenesis; preeclampsia.