Progesterone is a powerhouse hormone that supports pregnancy by thickening the uterine lining, preventing contractions too early, and helping the body sustain a growing baby. It also plays a role in preparing the breasts for milk production.

Are you breastfeeding? Check out our other articles: Breastfeeding advantages, Breastfeeding FAQ, and Breastfeedings tricks for a perfect latch

During pregnancy, progesterone levels skyrocket by the third trimester. This hormone works alongside estrogen to maintain a stable environment for the baby. Progesterone is critical for maintaining the pregnancy by preventing uterus contractions and premature labor. Progesterone also prepares the breast tissue for lactation and even suppresses the maternal immune system so that the foreign tissue of the fetus is not rejected (Source 1).

Once the placenta is delivered, progesterone plummets almost immediately, which can contribute to postpartum mood swings and the infamous “baby blues”. This sudden drop is why many new moms feel like their emotions are all over the place. Hormones post birth shift rapidly during the first days, making this period feel unpredictable, yet by day 4 or 5 progesterone and estrogen start to rise again on their way back to normal levels and work to support breastfeeding and uterine recovery via postpartum cramping.

For non-breastfeeding moms, progesterone levels stabilize within a few weeks postpartum. If you’re breastfeeding, they remain lower due to prolactin (the milk-making hormone) until you wean.

Estrogen isn’t just about periods—it supports fertility, pregnancy, and overall well-being. It helps regulate mood, maintains bone health, and keeps skin and hair looking vibrant. EStrogen  has been thought to contribute to postpartum depression, yet research shows that it is not so straightforward. There are many other factors too such as circadian biology, inflammation, psychosocial challenges and corticosteroids (Source 2).  

Estrogen levels triple or even quadruple during pregnancy, helping the uterus grow, increasing blood flow, and preparing the mammary glands for lactation (Source 1).

After birth, estrogen takes a steep nosedive, sometimes to levels even lower than before pregnancy. This is one reason why many women experience night sweats, vaginal dryness, lower sex drive, and postpartum hair loss.  Hormones post birth can impact how you feel both physically and emotionally.

Experiencing postpartum hair loss? We can help, Julie, a pharmacist and trichologist and one of our teacher has some products for you, here.

For non-breastfeeding moms, estrogen begins rising again after 6–12 weeks and should be back to normal around six months. If you’re breastfeeding, estrogen stays low (which can impact libido) until you reduce or stop nursing.

Oxytocin is known as the “love hormone” because it fosters emotional bonding and feelings of connection. What does oxytocin do? It also triggers uterine contractions during labor and helps with milk letdown during breastfeeding.

Oxytocin levels gradually rise throughout pregnancy, peaking during labor to stimulate contractions. It also helps form the deep emotional connection between mom and baby.

Oxytocin remains elevated postpartum, especially in breastfeeding moms, as it is released during skin-to-skin contact and nursing. This hormone reduces stress, promotes healing, and strengthens maternal instincts, contributing to some of the breastfeeding advantages for baby and for mom. Our hormones post birth are all working together, and oxytocin rises in part to compensate for the huge drop in progesterone and estrogen. Yet mothers, especially those who are not breastfeeding, may still feel some “baby blues” due to the oxytocin decrease after birth.

Oxytocin levels remain high for as long as breastfeeding continues. In non-breastfeeding moms, levels start to decline within a few weeks postpartum but remain responsive to social bonding and affectionate touch.

Cortisol is often called the “stress hormone” because it regulates energy, metabolism, and the body’s response to stress. It naturally rises in the morning to help us wake up and falls at night to promote rest. Working in the same way also for our babies, many parents aim to follow the famous wake windows.

Pregnancy is a natural state of high cortisol. This increase helps regulate baby’s development and prepares mom’s body for the stress of labor (Source 3).

Many new moms feel overwhelmed due to the way hormones post birth influence stress and mood. After birth, cortisol levels don’t immediately drop—in fact, they may stay high due to sleep deprivation, the demands of newborn care, and postpartum anxiety (Source 4). Indeed research has shown a positive correlation between high cortisol levels and depressive symptoms postpartum. While there are many factors that contribute to risk of postpartum depression, our natural levels of hormones post birth do play a role.

Cortisol gradually balances out over several months, though prolonged stress (hello, motherhood!) can keep it elevated. Self-care, nutrition with a solid postpartum diet, and support are key in managing cortisol post-birth.

Melatonin is the hormone that tells your body when it’s time to sleep. It rises at night to promote rest and falls in the morning when it’s time to wake up. Hormones post birth affect one another, for example melatonin also impacts serotonin levels and can contribute to a negative mood.

Melatonin increases significantly after 24 weeks and peaks in the third trimester to help regulate the baby’s circadian rhythm. It also supports fetal brain development, and your baby receives maternal melatonin via the placenta which lasts until about week 1 of life. But once again the hormones post birth are not stable, and your baby does not produce their own melatonin until around 6 weeks of age. Learning about these fluctuations can help immensely to establish an effective newborn sleep schedule.

After delivery, melatonin levels can be disrupted, especially if sleep patterns are erratic (which, let’s be honest, they usually are with a newborn). New moms often experience lighter sleep, more awakenings, and overall sleep deprivation. Hormones post birth play a huge role in postpartum sleep struggles.

Once you start getting consolidated sleep (which depends on your baby’s sleep habits), melatonin production improves. Prioritizing dark, quiet environments, consistent sleep routines and morning natural light can help reset or regulate your body’s clock.