Milk synthesis occurs continuously, as lactocytes produce lipids, lactose, proteins, and immunoglobulins that comprise human milk. Milk secretion occurs intermittently, when oxytocin stimulates the milk ejection reflex, causing contraction of myoepithelial cells and secretion of milk. Milk let ROCK1 down is inhibited by stressful stimuli. 71 For the infant to transfer milk, he or she must latch successfully. Infant suckling stimulates release of oxytocin and production of prolactin, and facilitates transfer of milk from the areola to the infant��s mouth. If the breast is not emptied regularly, engorgement occurs. This accumulation of milk in the alveoli appears to downregulate prolactin receptors in the mammary epithelium, leading to reduced milk production.

72 Successful establishment of lactation requires removal of progesterone and estrogen with delivery of the placenta, followed by a cycle of milk let down, successful latch, and removal of milk. Obstetricians can facilitate this process of ��let down, latch, and moving milk�� by encouraging immediate skin-to-skin contact after birth, followed by feeding on demand and ��rooming in,�� keeping the mother and infant together during the postpartum stay. Of note, in a small observational study, Keefe73 found that mothers who kept infants in their rooms at night slept as much as those who send their infants to the nursery. Hospital Practices and Breastfeeding Success Data from randomized studies show that maternity care practices have a substantial impact on breastfeeding success and infant health outcomes.

In the PROBIT trial,17 intervention hospitals implemented the BFHI. This set of evidence-based guidelines was developed by the WHO to increase initiation and duration of breastfeeding.74 Kramer and colleagues33 found that the intervention increased duration of exclusive and total breastfeed through the first year of life and resulted in improved health outcomes ranging from gastroenteritis to school-age verbal IQ. The BFHI has been widely implemented around the world, reaching more than 15,000 maternity hospitals in 134 countries. However, in the United States, fewer than 100 hospitals are certified as Baby Friendly. A recent study by the Centers for Disease Control and Prevention6 surveyed 2687 maternity centers to measure implementation of BFHI guidelines. The mean score was 63 out of 100 possible points.

The authors found that routine practices in many maternity hospitals are not supportive of breastfeeding. For example, 65% of hospitals reported that staff advise mothers to limit duration Batimastat of suckling at each feeding, and 70% distribute formula company marketing packs to breastfeeding mothers, despite evidence that both practices reduce breastfeeding success. Obstetricians can help close this quality gap by supporting efforts to eliminate outdated practices and providing evidence-based support for breastfeeding.