Ambiguous sex: prevalence at birth in a University Obstetric Wards in Santiago, Chile

Background: Ambiguous sex has a great phenotypic variability and is a serio us medical and social problem. Aim: To study the prevalence of ambiguous se x among newborns. Material ans methods: As part of the ECLAMC (Cooperative Latin American Study of Congenital Malformations) all newborns with malform ations are registered and the next normal newborn is considered as a contro l. Results: 50.253 births occurred (between malformations was 6.78% and the prevalence of ambiguous sex was 4.7 per 10.000 births. Affected children h ad a lower birth weight, lower gestational age and a lower maternal age tha n cardiovascular systems (60.7%). Thirty two percent of affected children a nd specific syndromes. Conclusions: The prevalence of ambiguous sex in this study was 4.7 per 10.000 births, which is higher than that reported in the ECLAMC (1.9 per 10000).