Influencers of Milk Production

Most people know about prolactin and oxytocin as the hormones of lactation, but do you know how they work and what other hormones, neurotransmitters, and proteins can decrease your milk production? These are known as influencers of milk production.

Prolactin is the hormone responsible for development of mammary glands and milk production. The best way to increase prolactin is with comfortable suckling or nipple stimulation.

Oxytocin is known as the love hormone, increasing feelings of attachment, trust, and bonding. Spikes in oxytocin cause contractions of mammary alveoli, leading to milk ejection reflexes (aka let-downs). These let-downs increase milk flow out of the breast and allow milk fat to be released from the ductal walls, decreasing risk of blocked ducts and increasing calorie content of milk. Oxytocin also decreases dopamine (read on to find out what dopamine does to milk production). Oxytocin levels are increased by activating sensory neurons, such as holding baby skin-to-skin, smelling your baby, and comfortable suckling or nipple stimulation.

Prolactin and oxytocin act independently but their combined action is essential for lactation.

Dopamine is both a hormone and a neurotransmitter that is controlled partly by oxytocin. Dopamine blocks prolactin! Dopamine levels drop during sleep and immediately increase upon awakening. It is ideal to remove milk when dopamine levels are low, so good idea to feed or pump during the night, and definitely as soon as you wake up. And getting sleep when you can is ideal to increase prolactin.

The feedback inhibitor of lactation (aka FIL) is a protein that decreases milk production anytime your breasts become full of milk. Anytime your breasts get engorged or hard because of being overly full of milk, this protein kicks in to permanently decrease milk production. This is how people who do not want to breastfeed their babies end up drying up their milk supply. So being sure you do not reach your maximum breast capacity (see blog that describes milk/breast capacity for more information) is paramount to a robust milk supply.