Pregnancy Hormones

Hormones, Hormones, Hormones… What are the major pregnancy hormones and how will they affect your body both before and after delivery?

This is a copy of the post that originally appeared on The Push Revolution.  Learn more about Dr Courtney Amerin and CNM Katie Danielson below!

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I recently interviewed Courtney and Katie on the Growing Our Family Pregnancy Podcast! You can find the full episode with links HERE, or listen on AppleGoogleSpotifyPandora, or wherever you get your podcasts! ! 

Have you ever wondered what hormones were and how they were related to pregnancy and postpartum? In our recent podcast (The PUSH Revolution Podcast on iTunes), we sat down and discussed a few important ones that we thought you should know about. We also briefly touched on what kind of normal changes you can expect after you have a baby. 

One of the biggest reasons we wanted to bring light to these topics is that hormones often have a lot of negative associations with them. We hear over and over again how they make you crabby, tired, decrease your sex drive, make you gain weight, etc., etc., etc. And while there may be some truths behind some effects, it’s hard to point fingers and say for sure if it is just that: HORMONES! 

What exactly is a hormone in the first place?!

Hormones act as a kind of instant messenger system for the body. They are released into the bloodstream and travel to different parts of the body and attach to cells which trigger them to start a process or make another hormone. Hormones can affect your growth, your appetite, and metabolism when puberty and menopause will start and can even affect fertility. They are more than a symptom, they are the text messages of the body, sent from one area to another to coordinate your body and make the magic happen!


HCG is the first pregnancy hormone, it’s what all of the over-the-counter pregnancy tests look for, as well as what your providers will test for. This hormone is produced by the cells that are surrounding the pregnancy. HCG tells your ovary where the egg was released to turn that cyst into what is called the corpus luteum, and that is what provides the progesterone to keep the pregnancy going in the first trimester. It’s like a feedback loop between your uterus and your ovary. HCG doubles every 48 hours in the first 10 weeks and peaks around 2-3 months (or 60-90 days) but is present during the entire pregnancy. This means that any time in your entire pregnancy, you can take an over-the-counter pregnancy test and it will come back positive.

HCG isn’t a very specific number all by itself. Providers don’t usually look at the specific number, but instead will look at how that number is multiplying as your pregnancy progresses. This means that even if two women conceive on the same exact day and take a test at the same moment, their HCG levels can be different, and that is normal. Your levels can also depend on other factors such as if you are carrying a singleton or multiples.

Over the counter pregnancy tests can start to detect HCG levels around 5 days before your missed period. Unless your provider is running a blood test, their pregnancy tests are pretty much the same as what you can get over-the-counter. And just to note, there is no difference between the $30-$40 pregnancy tests and the $1 pregnancy tests. 


Estrogen is a sex hormone that is produced mainly by the ovaries but is also produced in our fat cells and adrenal glands. It is regulated by something called a feedback system that acts as a checks and balance system to make sure that you have the right amount of hormones circulating in your body.  This is an amazing hormone that actually changes based on where you are in your life, such as in your childbearing years, pregnancy or postmenopausal. Estrogen affects many aspects of a person’s life: it leads to breast development, helps keep our bones strong, regulates our periods, and helps to further develop the uterus and vagina. 

During pregnancy, estrogen increases significantly and helps the uterus grow-and grow it does! It goes from being the size of your fist to the size of a watermelon in 9 months! It also helps trigger parts of the baby’s development and regulates other hormones. Estrogen also causes some noticeable outward changes too, like facial skin darkening (also called melasma or the “mask of pregnancy”) and the linea negra, or dark line, which is a dark line that can appear down the middle of the abdomen. These usually fade over time once pregnancy is complete.

Essentially, estrogen is the party planner of hormones: it wants everything to GO GO GO!


Progesterone is an important hormone that sustains pregnancy. It also has many roles like stimulating breast tissue growth, helping the uterus grow and softening pelvic ligaments.

 In pregnancy, the most important role of progesterone is decreasing smooth muscle contractions in the body. There are many smooth muscles in your body. These are muscles that you don’t have control over such as the lining in your stomach or blood vessels. The decrease in smooth muscle contraction can lead to constipation, heartburn, it can also lead to kidney infections from bladder infections. The high levels of progesterone will continue throughout the pregnancy, until the birth of the placenta. 

Progesterone is the peacekeeper of hormones: it wants everything to just chill and relax while the baby grows.


Relaxin’s purpose is to make things nice and soft during pregnancy. During the menstrual cycle, it helps by inhibiting contractions and preparing the lining inside the uterus to help it prepare for a pregnancy. It’s going to be at the highest levels during the first trimester, which is when a lot of women will notice round ligament pains. You’ll also hear about it again during the third trimester of pregnancy when you are experiencing some hip, back, symphysis pubic, or other pains.

Because Relaxin works on softening all of your ligaments up, it’s important to be mindful of how you are moving, practice getting up slowly, and even sleeping with a pillow between your legs to help keep you joints in a proper alignment. Relaxin is so important to help your hips and pelvis open up in preparation for that baby. However, like most other hormones, it is not specific to just your pelvic region. All of your joints will start to loosen up which can cause other issues such as knees popping out of place or pains in areas like your wrists and elbows.   


Known as the “love hormone”, oxytocin is probably the most talked about hormone during and after pregnancy.  It helps you bond with someone and gain trust with them. During intercourse, oxytocin is secreted which helps you bond with your partner. But, oxytocin is also secreted during breastfeeding and cuddling with your newborn so you start bonding with them too!

During pregnancy, the main role oxytocin plays is during labor to create strong rhythmic contractions to help deliver the baby and help stop bleeding after the baby is born. Postpartum, oxytocin help allow the milk in your breast to come out during breastfeeding.

Sometimes during delivery, we use synthetic oxytocin (Pitocin) as a tool to help start contractions if labor hasn’t started naturally, or strengthen contractions if labor has stalled. We also use synthetic Pitocin immediately postpartum to help contract the uterus and decrease the risk of postpartum bleeding after the placenta has been delivered.


Prolactin is often associated with lactation and milk production. This hormone is the number one influencer in breast development and milk production. Prolactin creates the milk and oxytocin opens the gate! 

It usually takes 3-4 days after the birth of the baby for the breasts to secrete milk or to have “your milk come in.” This is not to say that your breasts are empty when you deliver though. The first form of milk is called colostrum and this is the most nutrient-rich milk you will produce and is very good for your baby. For the first few feeds, your milk will be more thick and yellow (colostrum) and then will change to a thinner white milk with the help of prolactin. 

It can feel like your breasts are up to your chin! This is normal and will pass! You might have a slight elevation in your temperature or “milk fever. ” Producing milk is HARD WORK and you might find yourself feeling like the hungry caterpillar trying to eat everything in sight. Don’t panic: this will pass!! Breast or chest feeding is a supply and demand chain. The more you do it, the more oxytocin and prolactin you will produce and the more milk you will make. 

Is this normal?! 

Let’s review a few normal changes that your body will undergo after having a baby, all without you having to think about it!

The Uterus

The uterus, also known as the womb, is an amazing organ. It houses the baby during development and goes from being the size of a watermelon back to the size of your fist in about 6 weeks after the baby is born! During this process, you may experience cramping and pain, especially with breastfeeding (thanks oxytocin!!). To help ease these symptoms you can try: 

  • Emptying your bladder
  • Laying down on your abdomen with a pillow or heating pad underneath you
  • Taking pain medication such as Tylenol, Ibuprofen or an herbal tincture, such as After Ease


Vaginal bleeding, also known as Lochia, is a normal part of recovery. It can be a bummer to go from NO bleeding for 9 months to having a lot of it overnight! You can expect this bleeding to last about 4-6 weeks and it will change over that time in color and amount. During the first 3-5 days, expect to see dark red bleeding. As the weeks go on, it will become brown, then tan, then white, before stopping altogether.

Especially during the first few days, it can be normal (and sometimes alarming) to see a blood clot in the toilet or on your pad. Often times this is FINE. If you have been laying down or sitting for a while and you stand up, you might have a clot come out. Basically what is happening is the blood is pooling in the vagina and forming a nice sized clot. When you stand up, it has to come out! 

If you continue to pass clots that are larger than a golf-ball, or you are saturating your pad in less than an hour for more than 2 hours, or the blood had a foul smell to it you should contact your provider immediately. 


Your breasts may look completely foreign to you. They have been undergoing many changes during pregnancy in preparation to produce milk for the baby. As we said previously, you can expect colostrum for the first few days and your normal milk to come in around days 3-4 after baby is born, however, everyone is DIFFERENT, so it could be sooner or it could be later. The best advice is if you are planning on nursing your baby, continue to feed or pump. The more you do it, the more it will stimulate your milk production. 

Your breasts may be slightly firm or engorged during the first few days, but this should pass quickly. Make sure that you are alternating sides and emptying the breasts completely. We always share the advice that when milk comes out of one side, it will also come out of the other! You can wear nursing pads or a milk collection device such as the Haakaa Breast Shells Nursing Cups Milk Saver to save your shirt from wet spots. 


Your kidneys are going through some changes too! It’s not uncommon to wake up in the middle of the night feeling like you are drenched in sweat. You aren’t overheating, and chances are you don’t have a fever, it’s most likely your kidneys working hard to restore balance. The good news is this doesn’t last long, and you can dress appropriately and throw down a towel that you can change with each sleep. Make sure you are drinking plenty of water to combat loss during sweating.


Some people have a hard time feeling the sensation to pee after having a baby. If you had an epidural, it may be harder to recognize the urge to go in the first few days, especially if you had a catheter in place. Make sure you are drinking plenty of water and trying to empty your bladder every few hours. 

Abdominal muscles

After months of stretching and making room for the growing baby and growing uterus, it’s not uncommon to have some separation of the front abdominal muscles, also known as diastasis recti. This is a measurable gap between your abdominal muscles. Often people measure this gap by the number of fingers you can place inside this gap. This can lead to back pain in future pregnancies. Sometimes this gap will heal in the first 6-12 weeks and resolve on its own, but if the gap is large enough, you might need to do some physical therapy. Check-in with your healthcare provider before starting any exercises. 

Your Period

Ovulation and menstruation are usually inhibited by prolactin during lactation. Prolactin stops estrogen from being made and thus stops your menses and period. You can expect your first period within 6-8 weeks after the baby if you are NOT breastfeeding. If you ARE breastfeeding, it might be a while before it returns. 

This is just the tip of the iceberg when it comes to the normal things that surround the postpartum period. You can look for more on upcoming podcasts/blog posts/and future course material that the PUSH Revolution has to offer. 


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Meet the Authors

Pregnancy Hormones with Courtney and Katie

We’re Courtney and Katie, a Doctor and Certified Nurse Midwife/Women’s Health Nurse Practitioner team here to provide expert advice and evidence-based information to empower parents in achieving understanding, support, and health in the postpartum period.

The Push Revolution
Push Revolution Podcast