Promoting awareness of neonatal menstruation
Neonatal uterine bleeding (NUB) has been carefully studied in the past through case reports, small series, clinical cohort studies, pathology investigations of fetal and neonatal. Following a historical recount, this review summarizes biological mechanisms conditioning NUB, starting from the persistence till birth of an 'ontogenetic progesterone resistance' (OPR), causing decreased responsiveness of target tissues to bioavailable progesterone.