Prolactin and the Importance of Nighttime Nursing or Pumping

Prolactin and the Importance of Nighttime Nursing or Pumping

Written by Wendy, IBCLC.

Waking up to nurse your baby can be exhausting. After a while, most of us mamas get used to it, and babies and toddlers do eventually outgrow the need to nurse at night (when that is varies widely!). But when you are in it, it is so easy to feel irritated, defeated … and did I mention, exhausted?

Rest assured, you are truly doing what is best for your baby. Not only is nighttime nursing an opportunity to snuggle and meet your baby’s need for love and nutrition, but there are actually some really cool science facts about why nighttime nursing (or pumping) is so important when it comes to milk supply.


It’s all about hormones, baby. The two main hormones at work during breastfeeding are oxytocin and prolactin. Oxytocin is the hormone responsible for milk removal and let-down. In response to suckling or pumping, the release of oxytocin causes the cells around the alveoli to contract and release milk.

During pregnancy, prolactin helps in the development of your mammary tissue in preparation for breastfeeding. After birth, prolactin is secreted every time your baby suckles or your breasts are pumped. Prolactin sends the message to your pituitary gland to continue making milk for your baby. The more you stimulate your breasts, the more prolactin will be released, and more milk you will produce. It’s a beautiful thing.


Although prolactin is released most closely in response to nursing or pumping, it has its own natural secretion schedule as well. Studies have shown that prolactin release follows a circadian rhythm, with highest levels of secretion at night and in the morning. Researchers aren’t sure why, but if you think about it, nighttime and mornings are when you and your baby are most likely to be still and get to the business of feeding, even if you are most exhausted then.

However, most of us breastfeeding moms don’t need a study to tell us that our bodies produce the most milk at night and in the morning. Any mama who has missed a feeding them will tell you that her overfilled breasts sent the message to her loud and clear!


The next time anyone criticizes you for nursing your baby at night, you can tell them “It’s biology!” and send them on their merry way. Knowing that nature designed it so your baby would naturally want to eat more at night can be reassuring during those all-night nurse-a-thons when it feels like the last thing you want to do is nurse.

Especially during the first six weeks, emptying your breasts at least every 2-3 hours, including at night, is vital to establishing a robust milk supply and keeping that prolactin stimulated. But your prolactin levels are highest at night and the morning throughout the duration of breastfeeding, and many of us find that our babies continue to want at least a few nighttime sessions and early morning chow-down for quite a while. Take solace in the fact that this is normal, and an important way to maintain your supply.


Moms who are dealing with low milk supply and are trying to balance supplementing with breastfeeding may find that during the night time or morning hours, they actually don’t have to supplement as much, because their milk supply is higher and their baby is more satisfied at the breast. Knowing how the prolactin circadian rhythm works and taking advantage of those surge times can help you make a nursing/supplementing schedule that feels more natural and works for you.

The same goes for moms who need to pump for any reason. For example, if you are trying to build up a pumping stash in preparation for returning to work, you may want to pump first thing in the morning, when you are guaranteed to have a ton of milk, and when your baby will still have plenty of milk leftover. Keep in mind, too, that if you are exclusively pumping, it is vital to pump once or twice in the middle of the night to maintain your milk supply.

How about you? Do you notice a milk supply surge at night and in the early morning? Did you know about the prolactin/milk supply link before?

Picture of Wendy


Wendy (she/her) is a writer, editor, and IBCLC. She writes frequently about breastfeeding, parenting, and health. She believes in the power of providing families with smart, evidence-based information so they can make decisions that work best for their family. Find her

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