Everything You Need to Know

To say that a woman’s body goes through a lot during pregnancy and giving birth is a gross understatement. But the process of pregnancy, labor, and delivery can be made just a little bit smoother by the body’s reproductive hormones that support the ability to grow and deliver a baby, and help you recover and care for your new baby in the weeks and months after delivery. Leading this charge are four essential hormones that govern many of these processes: estrogen, progesterone, oxytocin, and prolactin.

Hormones are chemical messengers that coordinate different functions in your body. Men and women have more than 50 hormones, which are part of the endocrine system, and they are responsible for everything from regulating blood sugar and blood pressure to controlling your mood.

For women, several hormones play a big role during and immediately after pregnancy, the period that’s know as postpartum (which the American College of Obstetrics and Gynecology defines as lasting up to 12 weeks after giving birth). These include:

• Estrogen: This group of sex hormones are an important part of reproductive health, including getting the uterine lining ready for the baby, helping to maintain the pregnancy, and playing a role in delivery. Normally formed in the ovaries, it is largely produced in the placenta during pregnancy. Pre-pregnancy estrogen levels vary quite widely in women and can be anywhere from 30 to 400 pg/mL on a blood test (depending on the time of the menstrual cycle), then increase over the course of a pregnancy.

• Progesterone: Another sex hormone, progesterone levels increase during pregnancy to help maintain the pregnancy, thicken the lining of the uterus, and suppresses contraction to avoid preterm labor. In someone who isn’t pregnant, progesterone levels vary based on the stage of the menstrual cycle, with normal levels being 0.1 to 0.7 ng/mL during the follicular stage and 2 to 25 ng/mL during the luteal phase. Levels then climb throughout pregnancy.

• Oxytocin: This hormone is released to help produce contractions during labor. It’s also involved in milk production and helps strengthen the bond between you and your baby. Like estrogen, oxytocin levels also very widely pre-pregnancy and increase throughout pregnancy, spiking at delivery.

• Prolactin signals breast tissue to grow during pregnancy and helps produce milk for breastfeeding after birth. Nonpregnant women have prolactin levels below 25 ng/mL. Levels then climb throughout pregnancy and spike after delivery.

Immediately after delivery of both the baby and the placenta (this part is key), your hormone levels start to change rapidly, creating a variety of changes.

Estrogen Drops

“During pregnancy, the placenta produces high levels of estrogen. Once the placenta is delivered, this source of estrogen is abruptly removed,” explains Salome Masghati, M.D., a gynecologist based in Las Vegas, NV. This creates an abrupt estrogen deficiency, which can lead to a host of symptoms in the first few weeks postpartum, including:

• Changes in skin and hair

• Fatigue

• Mood swings

“The mood changes are due to the fact that estrogen usually supports neurotransmitter levels in the brain associated with mood,” explains Dr. Masghati.

Progesterone Drops

“Similar to estrogen, progesterone is high during pregnancy and drops rapidly after delivery,” says Sara Twogood, M.D., a board-certified obstetrician and gynecologist based in Los Angeles and the co-founder of Female Health Education, an online patient education platform. That’s because, like estrogen, progesterone is produced by the placenta, which follows the baby out.

“The lower levels of progesterone can help get rid of some of the unpleasant pregnancy symptoms like constipation and bloating, but the rapid drop is also thought to contribute to the baby blues and postpartum depression, too,” Dr. Twogood adds.

Prolactin Spikes

Unlike estrogen and progesterone, prolactin levels spike after delivery. “Prolactin is the hormone that helps with breast milk production,” says Dr. Twogood. “Its level increases significantly after birth and those first few days as milk is being produced.” This hormone is stimulated by breastfeeding, so the more frequent your attempts at nursing during these early weeks, the higher your levels of prolactin will be.

Oxytocin Remains High

Oxytocin, a.k.a. the “love hormone,” is the only one that is both high during pregnancy and remains high after delivery. “Oxytocin stimulates mothering feelings after birth as a mother touches, gazes at, and breastfeeds her newborn,” explains Dr. Masghati. “It is also released in response to breastfeeding and plays a key role in uterine contractions to reduce postpartum bleeding. It’s an important hormone for bonding between mother and baby, feelings of love and attachment, and milk ejection during breastfeeding.”

While prolactin is responsible for milk production, oxytocin is what causes the milk that is already in the breast to “let down,” or flow to the nipple for the current feed.

The period three to six weeks after delivery typically features a leveling off of sorts when it comes to postpartum hormones, as not much changes.

Estrogen Remains Low

Your body is still adjusting to the loss of the placenta, so estrogen production stays low, says Dr. Masghati. After you give birth, your ovaries will eventually become the primary estrogen producers again, but this could take some time. “It sometimes takes a few cycles until ovulation resumes normally. If a woman is breastfeeding, the lactation process further suppresses ovulation and estrogen production,” Dr. Masghati notes. “Continued low estrogen can maintain the initial postpartum symptoms such as mood swings and vaginal dryness.”

Progesterone Remains Low

Just like estrogen, this is the period in which progesterone production (which also happens in the ovaries) remains low because ovulation likely hasn’t restarted yet. “Women feel this in the form of persistent mood instability and other low-progesterone symptoms such as menstrual irregularity,” says Dr. Masghati.

Prolactin Remains High if Breastfeeding

As the hormone responsible for breastmilk production, prolactin levels will remain high if you are breastfeeding your baby. Physical stimulation of the nipple is what prompts prolactin to be produced, so the more often your baby eats, the higher your levels will generally be. “In most women, that will suppress ovulation, which keeps progesterone and estrogen levels low,” Dr. Masghati adds.

If you choose not to or are unable to breastfeed, your prolactin levels will be back to pre-pregnancy levels by this point postpartum.

Oxytocin Remains High

Oxytocin levels at this point are similar to prolactin. “Oxytocin levels remain high if breastfeeding continues because breastfeeding stimulates oxytocin release,” Dr. Masghati explains. “A woman will usually feel continued bonding and support for milk ejection.”

But even if you aren’t breastfeeding, oxytocin levels may stay elevated during this period. Pleasant, loving touch between the mother and baby stimulates oxytocin production, as does skin-to-skin contact.

The hormonal changes that occur around six months postpartum depend on two major factors: if you have started to ovulate and if you are still breastfeeding.

Estrogen Starts to Rise

“Estrogen levels can start to rise if breastfeeding goes down or is stopped, which can allow ovulation and normal menstrual cycles to resume,” explains Dr. Masghati. When you get your first period postpartum varies drastically from person to person.

If you are not exclusively breastfeeding, your period might come between six and 12 weeks postpartum and would be associated with rising estrogen levels. But if you are exclusively breastfeeding, you can expect your period to remain absent—and your estrogen levels to remain low—until you introduce formula and/or solid food.

Progesterone Starts to Rise

“As with estrogen, as breastfeeding decreases, the inhibitory effect on the hypothalamic-pituitary-ovarian axis lessens, allowing for the resumption of ovulation and progesterone production,” says Dr. Masghati.

You may be able to physically feel this change. “Women can feel more improvement in mood stability and regularity in menstrual cycles. They will usually have a bit easier time sleeping through the night and feel less irritable,” Dr. Masghati says. “However, the stress of being a new mom and having a newborn can still take a toll on sleep and nervous system, so sometimes those improvements aren’t always felt by the woman.”

Prolactin May Start to Drop

Whether this hormone decreases depends on whether or not you are still breastfeeding and how much. According to the most recent Breastfeeding Report Card from the Centers for Disease Control and Prevention (CDC), 24.9% of babies born in 2019 were still exclusively breastfed at six months old, while 55.8% of babies were still receiving some breastmilk, which leaves 44.2% with mothers who are not breastfeeding. If you fall into one of the first two categories, you’ll still be producing some prolactin. If you’re not breastfeeding, your prolactin levels will have returned to normal by this point.

Oxytocin May Start to Drop

“Lowering oxytocin can be felt through reduced milk ejection reflex,” notes Dr. Masghati. “But as long as the mother is breastfeeding, she will feel support for bonding and a positive mood when breastfeeding. As breastfeeding goes down, so do oxytocin levels. However, a mother can continue bonding with her child through hugging and physical touch.”

The answer to this question depends on how long you choose to breastfeed, if at all, and how long it takes for your menstrual cycle to return. But, in general, here’s how long it takes these hormones to return to normal, pre-pregnancy levels (note that these timeframes can be highly dependent on how long breastfeeding is continued):

• Estrogen: 12 weeks to 12 months postpartum, depending on when menstrual cycle resumes

• Progesterone: 12 weeks to 12 months postpartum, depending on when menstrual cycle resumes

• Prolactin: 1 to 2 weeks postpartum if not breastfeeding, or 1 to 2 weeks after breastfeeding is stopped

• Oxytocin: varies widely depending on the person, whether they are breastfeeding, and the amount of skin-to-skin contact and bonding they do with their baby

“Postpartum depression is a mood disorder of depressive and/or anxiety symptoms during the postpartum period,” explains Dr. Twogood. Around 70% to 80% of new mothers experience mood swings or some negative feelings (known as the “baby blues”) shortly after giving birth, according to the American Pregnancy Association. If those negative feelings don’t go away within a couple of weeks post-delivery, or they become more severe, you may have postpartum depression.

According to the government’s Office on Women’s Health, one in eight new moms report experiencing symptoms of postpartum depression in the year following childbirth. Per the Office on Women’s Health, these symptoms can include:

• Eating more or less than usual

• Feeling angry or moody

• Feeling guilty, shameful, or worthless

• Feeling sad or hopeless

• Loss of interest, joy, or pleasure in thing you used to enjoy

• Possible thoughts of harming the baby or yourself

• Sleeping more or less than usual

• Unusual crying or sadness

• Withdrawing from friends and family

It might seem logical to attribute the fluctuation in hormones during this time to the incidence of postpartum depression, but the explanation is more complex, experts say. “While lower estrogen and progesterone levels can contribute to postpartum depression, they are not the only cause,” notes Dr. Twogood. “Almost everyone postpartum experiences these low hormones but not everyone gets postpartum depression and anxiety.”

Just as your body knows what to do once you become pregnant, it knows what to do to help you recover and care for your baby postpartum. But while having the baby blues or feeling somewhat off for a couple of weeks is common among new mothers, anything more than that is worth a call to your doctor or health care provider.

“If the symptoms persist more than two weeks or are so severe that they interfere with a women’s ability to take care of herself or her baby, if she experiences thoughts of harming herself, the baby or others, if she doesn’t experience joy or feels overwhelmed to the point she can’t get out of bed, it is important to seek help as soon as possible,” says Dr. Masghati.

While self-care is important (including eating well and getting rest when you can), your doctor may recommend therapy, support groups, and in some cases medication to help reduce postpartum depression or anxiety.

This article was originally published January 23, 2023 and most recently updated July 9, 2024.

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