['The aim of this study is to examine the hypothesis that prolonged rupture of membranes (PROM) is associated with increased cord blood erythropoietin (EPO) concentrations, proportional to the duration of ruptured membranes.', 'This study is a prospective, cross-sectional, observational (noninterventional) cohort study of mother-infant pairs. Criteria for inclusion were as follows: active labor with or without ruptured membranes and vaginally delivered neonates. Excluded were infants with major factors known to be associated with a potential increase in fetal erythropoiesis.', 'A total of 40 mother-infant pairs were recruited. EPO was not influenced by duration of ruptured membranes and significantly correlated only with maternal body mass index.'] Does increased nucleated red blood cells count in prolonged rupture of membranes is not erythropoietin driven?