Ergonovine is no longer marketed in the United States. Ergonovine given in the immediate postpartum period lowers serum basal prolactin and suckling-induced prolactin possibly increases. However, the prolactin level in a mother with established lactation may not affect her ability to breastfeed. Ergonovine appears to decrease the rate of breastfeeding. Ergonovine is probably best avoided in mothers who wish to nurse, relying instead on suckling-induced oxytocin release to hasten uterine involution.