Human chorionic gonadotropin testing. Changing testicular response in infants with microphallus and gonadotropin deficiency.

The evaluation of microphallus often includes human chorionic gonadotropin (HCG) stimulation to evaluate testicular androgen production. The response in testosterone secretion after five days of stimulation with chorionic gonadotropin is abnormal in patients with either primary testicular defects or gonadotropin deficiency. The testes of gonadotropin-deficient children do respond if the chorionic gonadotropin therapy is continued for six weeks. The current study reports a normal response to the short course (five days) of chorionic gonadotropin therapy in two 2-month-old patients with XY chromosomes with microphallus whose clinical course and repeated testing at age 3 or 4 years indicated gonadotropin deficiency. The normal response in the neonatal period is probably the result of maternal chorionic gonadotropin priming of the fetal testes in utero. These results indicate that HCG testing is an unreliable method for identifying gonadotropin deficiency in the neonatal period.