High prevalence of micropenis in 2710 male newborns from an intensive-use pesticide area of Northeastern Brazil

Exposure to endocrine-disrupting chemicals (EDCs) has been suggested to contribute to the increasing trends of external genital malformation in male newborns. In Northeastern Brazil, the poor sanitary conditions found in the favelas encourage the widespread use of pesticides. This 2-year study of a total birth cohort of full-term male newborns in the regional hospitals of Campina Grande (Paraíba, Brazil) sought to (1) accurately establish for the first time the incidences of neonatal male genital malformations, (2) investigate the endocrine and genetic aetiologies of these malformations, and (3) evaluate their associations with possible prenatal exposure to EDCs. A total of 2710 male newborns were explored for cryptorchidism, hypospadias and micropenis. Cases were referred to the Pediatric Endocrine Clinic for endocrine and genetic investigations, and all parents were interviewed about their environmental/occupational exposure to EDCs before/during pregnancy by paediatric endocrinologists using a detailed questionnaire. We observed 56 cases of genital malformation (2.07%), including 23 cryptorchidism (0.85%), 15 hypospadias (0.55%), and 18 micropenis (0.66%). All cases exhibited normal/subnormal testosterone production and none presented androgen receptor or 5α-reductase gene mutation. More than 92% of these newborns presented foetal contamination by EDCs, as their mothers reported daily domestic use of pesticides (i.e., DDT) and other EDCs. Most of these undervirilized male newborns presented additional EDC contamination, as 80.36% of the mothers and 58.63% of the fathers reported paid or unpaid work that entailed the use of pesticides and other EDCs before/during pregnancy for the mothers and around the time of fertilization for the fathers. The high rate of micropenis in our population associated with an elevated percentage of parental environmental/occupational exposure to EDCs before/during pregnancy indicates that foetal contamination may be a risk factor for the development of male external genital malformation.