Breastfeeding, prolactin, and ovulation during the puerperium

A series of hormonal changes follows the completion of pregnancy. These changes are necessary for the initiation and maintenance of lactation for the survival of the infant and for the prevention of another conception. Hormones involved in this process include estrogen, progesterone, insulin, glucocorticoids, thyroid, growth hormone, and human placental lactogen. Prolactin is a major regulating factor in the immediate postpartum period for the initiation and establishment of lactation. In a non- breastfeeding individual, serum prolactin will drop to nonpregnant levels within 1 week after delivery. In a lactating woman, prolactin levels may remain elevated for up to 80 days postpartum. Despite normalization of prolactin levels after that time interval, milk production and lactation may be sustained, providing that frequent breastfeeding continues. Vigorous breastfeeding patterns and nipple stimulation are factors that sustain lactation while also delaying the resumption of ovulation, even in the presence of normal prolactin levels.