The Role of Prolactin in Breastfeeding

Prolactin is a hormone produced by the pituitary gland in the brain, and it plays a crucial role in the process of lactation, or milk production, during breastfeeding. When a baby is born, the mother's body undergoes several changes to prepare for breastfeeding, and prolactin is one of the key hormones that drive these changes.

Prolactin is primarily responsible for stimulating milk production in the mammary glands. It does this by binding to receptors in the breast tissue, which triggers the synthesis of milk components such as lactose, lipids, and proteins. The amount of prolactin in the mother's blood increases significantly during pregnancy, but it is kept in check by high levels of estrogen and progesterone, which prevent milk production until after the baby is born.

Once the baby is born, the placenta is delivered and the baby begins to suckle at the breast, this stimulation sends signals to the hypothalamus, another part of the brain, which in turn stimulates the pituitary gland to release more prolactin. The more frequently the baby breastfeeds, the more prolactin is released, which increases milk production.

The prolactin level is highest about 30 minutes after the beginning of the feed, so its most important effect is to make milk for the next feed. During the first few weeks, the more a baby suckles and stimulates the breasts, the more prolactin is produced, which means more milk is produced. That’s why we say that milk production is driven by supply and demand. The more the baby demands, the more milk is made! Interestingly, prolactin levels have a typical 24-hour cycle — just like the human body's circadian rhythm. Prolactin peaks at night between the hours of 11 pm and 2 am, while the lowest prolactin levels happen in the late afternoon to early evening. This is why babies typically cluster feed overnight and in the late afternoon/early evening. Short frequent feeds help to build and increase your milk supply.

In addition to its role in milk production, prolactin also has several other effects that are important during breastfeeding. For example, it helps to suppress ovulation, which can prevent the mother from becoming pregnant again too soon after giving birth. But breastfeeding alone is not a reliable method for birth control, and other forms of contraception are recommended.

Prolactin also has a calming effect, which can be helpful during the stress and sleep deprivation that often accompany the early days of breastfeeding. This is because prolactin stimulates the production of oxytocin, another hormone that is involved in milk production and is also known as the "love hormone." Oxytocin is released when the baby suckles at the breast, which not only stimulates milk production but also produces a feeling of relaxation, bonding, and contentment in the mother.

Interestingly, research has also shown that prolactin may have a role in maternal behavior and bonding with the baby. Studies have found that mothers who have higher levels of prolactin during breastfeeding have more positive feelings toward their babies and are more likely to engage in nurturing behaviors such as holding and cuddling.

It is worth noting that while prolactin is a key hormone in milk production during breastfeeding, it is not the only one. Other hormones such as estrogen, progesterone, and cortisol also play important roles in regulating lactation and the production of breast milk. Additionally, a variety of environmental and lifestyle factors can also affect milk production and breastfeeding success.

In some cases, mothers may have difficulty producing enough milk or may experience other breastfeeding challenges despite adequate prolactin levels. In these cases, it is important to work with a lactation consultant or healthcare provider to identify causes for any underlying issues.

Prolactin is a crucial hormone in the process of lactation and breastfeeding. It stimulates milk production in the mammary glands, suppresses ovulation, and helps to promote feelings of relaxation and bonding between mother and baby. While it is not the only hormone involved in lactation, it plays a key role in ensuring that the baby receives the nourishment needed during this important time.

If you have questions about milk supply or milk production, please feel free to reach out to a Team Nourish Lactation anytime!