Fetal sex alters maternal anti-Mullerian hormone during pregnancy in cattle

•Intercotyledonary membranes and cotyledons were found to express AMHR2 between days 38–80 of gestation.•Fetal AMH level between gestation days 54 and 220 was significantly higher in male vs. female fetuses.•Placenta expresses AMHR2 between gestation days 38 and 80 at similar levels in both fetal sexes.•Fetal sex alters maternal Pl AMH during pregnancy in cattle. Anti-Mullerian hormone (AMH) is expressed by both male and female fetuses during mammalian development, with males expressing AMH earlier and at significantly higher concentration. The aim of the current study was to explore the potential impact of pregnancy and fetal sex on maternal AMH and to determine if plasma (Pl) AMH or placenta intercotyledonary membrane and cotyledonary AMH receptor 2 (AMHR2) mRNA expression differ in pregnant cows carrying male vs. female fetuses. AMH levels in blood were measured using a bovine optimized ELISA kit. Cows pregnant with a male fetus were observed to have a significantly greater difference in Pl AMH between day 35 and 135 of gestation. Average fetal AMH level between 54 and 220days of gestation was also observed to be significantly higher in male vs. female fetuses. Intercotyledonary membranes and cotyledons were found to express AMHR2 between days 38 and 80 of gestation at similar levels in both fetal sexes. These findings support the hypothesis that fetal sex alters maternal Pl AMH during pregnancy in cattle.