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Prolactin and Oxytocin: Milk Makin' Stars

Sure, we all kinda know how breastmilk is made. Right? Baby latches, milk lets down, and well, milk comes a flowin'!

There's actually a lot of subtle moving parts that make it all work. Ladies, if you don't already think your body is an amazing design, we hope that reading this will give you a bit more appreciation for it!

IBCLC Kristi Ramey helps a breastfeeding mother

So outside of the mechanical forces necessary to signal a letdown (sucking), what else is involved?

"Stimulation of a brain area closely that has to do with the regulation of emotions, called the hypothalamus, produces oxytocin. When this is activated, it sends signals to the pituitary gland to produce different hormones. This includes those that take part in the breastfeeding process.

These hormones will travel through the blood to the mammary gland to stimulate those cells in charge of milk production (prolactin) and release (oxytocin)." 

What does that look like, in laymen's terms?

There are things (noises, smells, emotions, etc) that are supposed to signal "let's make milk" to our brain, which then begins to produce hormones. For example, when you are lactating and hear a baby cry, it can often trigger a letdown. That's the mammal brain being told, "There is a hungry infant nearby, let's solve that problem."

The milk makin' stars of lactation are prolactin and oxytocin.

Yes, you might recognize those from your childbirth ed classes, as they are also produced during pregnancy and birth!

Prolactin: This hormone is responsible for creating and growing mammary glands, as well as producing and filling those same glands during lactation. Every time you baby sucks at the breast, it stimulates the production of this hormone. The more you empty the breast, the more it signals to make this hormone. More demand=more hormone=more milk

This hormone can also reduce luteinizing hormone, which suppresses ovulation/menstruation. Feeding "on demand" instead of a strict schedule often extend this period suppression but not for a specific amount of time, and not for every woman!

Please note that it IS possible to get pregnant while nursing. Remember that you ovulate BEFORE you menstruate, so most women don't know their fertility has returned until they get that first period.

Oxytocin: Just like prolactin, this hormone is also triggered when baby suckles. However, instead of signaling milk production, oxytocin triggers the muscles around your milk ducts to squeeze. pushing the milk into the milk ducts. This is commonly referred to as the "letdown reflex". Some women feel each letdown (some as tingling, some as a zinging sensation) and some mothers don't feel anything at all!

Fun fact: This is also a hormone that encourages "inter-personal bonding", or emotional connection between people. It is a driving factor in your body's ability to appropriately bond with your newborn.

This all comes together to create the most nutrient rich food available for your baby.

Mothers really are incredible!

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