Hormones tend to get a bad rap during pregnancy—after all, they’re the culprit behind pesky symptoms like morning sickness, mood swings, and weird cravings. But your hormones also play a crucial role in preparing your body for a healthy pregnancy and supporting your baby’s development. Here’s a primer to some of the most important hormonal changes during pregnancy.
First Trimester Hormone Changes
After successful conception, your body starts to ramp up production of a few key hormones.
- Human chorionic gonadotropin (hCG). HCG may be the first hormone to hit your radar after successful conception, for one simple reason: It’s the hormone detected by home pregnancy tests.1 Produced by certain cells in the placenta, hCG helps to support production of estrogen and progesterone. In early pregnancy, hCG levels double every three days, peaking around the end of the first trimester.2
- Estrogen and progesterone. Even before conception occurs, these hormones play an important role by helping to prepare the uterus to support a pregnancy.3 During early pregnancy, estrogen and progesterone levels increase rapidly and—together with hCG—they help to support your baby’s growth. However, these hormones can also cause morning sickness, fatigue, and mood swings—along with a few symptoms you might not expect, like a stuffy nose or bleeding gums.4
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Relaxin. This hormone lives up to its name by helping to relax your ligaments and muscles. After ovulation, relaxin helps to prevent uterine contractions, making it easier for a fertilized egg to implant in the uterine wall. If conception is successful, relaxin levels continue to rise, loosening your ligaments and abdominal muscles so your belly has room to grow.5
Human placental lactogen (hPL). Like hCG, this hormone is produced by the placenta during pregnancy. Experts believe it plays a role in regulating metabolism and helping nutrients and glucose reach your growing baby. Levels of this hormone rise steadily throughout your pregnancy, then return to normal after baby arrives.6
As these hormones kick into high gear, you may find yourself dealing with symptoms like fatigue, nausea, and breast tenderness while your body adjusts. Hormone changes can also cause mood swings, which can make this emotionally heightened time even more challenging to navigate. Luckily, your hormones should start to level out in the second trimester.
Second and Third Trimester Hormone Changes
By week 12, your placenta has taken over hormone production.7 At this stage of the game, your hormones are helping to support your growing baby and prepare your body for labor and delivery. Some important hormone changes include:
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HCG. HCG levels peak around the end of the first trimester. Throughout your second and third trimesters, levels will taper off, which may help to ease some of your worst early pregnancy symptoms.
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Estrogen and progesterone. These hormones continue to increase gradually throughout pregnancy, peaking around week 32. This can mean a resurgence of mood swings in the home stretch—very inconveniently overlapping with the all aches, pains, and fatigue that come with those last few weeks of pregnancy.
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Relaxin. After peaking at the end of the first trimester, levels of this hormone slowly decline throughout the second and third trimester, then spike again before delivery. Relaxin helps the body prepare for delivery by softening the cervix and loosening the ligaments in the pelvis.
- Prolactin. As your pregnancy progresses, this hormone works alongside estrogen and progesterone to stimulate breast tissue development, getting your body ready for breastfeeding.8
- Cortisol. Levels of this “stress hormone” increase throughout pregnancy. By the end of the third trimester, your cortisol levels will typically be at least double their normal pre-pregnancy levels. That boost seems to play an important role in your baby’s development — elevated cortisol levels in the third trimester have been linked with better performance on infant cognition tests. However, a spike in cortisol early in pregnancy seems to have a negative effect — so be sure to make stress management a priority during pregnancy.
Labor and Postpartum Hormone Changes
Hormones play a vital role in kicking off labor, supporting delivery, and easing the physical transition from pregnancy to parenthood. Here’s what to expect during this stage of pregnancy.
- Oxytocin. This hormone does some heavy lifting during labor and after delivery. Oxytocin stimulates uterine contractions during labor, which helps to keep things progressing. Once your baby arrives, oxytocin causes contractions of certain cells around your milk ducts, promoting lactation. And in the days after delivery, oxytocin causes contractions that help to shrink the uterus back to its pre-baby size—an important part of the recovery process.9 Oxytocin is also released in response to physical affection (like baby snuggles!) and plays an important role in bonding.10
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Endorphins. During labor, your body produces these feel-good hormones to help ease pain and boost your mental wellbeing. If you opt for a medication-free birth, endorphin levels will keep rising as contractions get stronger; if pain medication is given, levels typically drop off.11
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Estrogen and progesterone. After delivery, estrogen and progesterone levels drop. This triggers the body to start lactation — but the sudden hormone shift can also cause mood swings, anxiety, or the “baby blues.” These emotional changes, which affect up to 80% of new mothers, can last up to two weeks.12 If you’re still struggling after two weeks, or you’re feeling really low, let your doctor know, as these can be signs of postpartum depression.
- Prolactin. The postpartum dip in estrogen and progesterone triggers the body to produce this hormone, which is essential for milk production.
These hormone changes may feel overwhelming at times, but rest assured they’re only temporary. Typically, hormone levels will return to normal around three to six months after delivery.
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How to Navigate Hormonal Changes During Pregnancy
Hormonal changes are a natural part of a healthy pregnancy—but we know they can feel like a lot to handle at times. These three simple lifestyle shifts can help support your physical and emotional wellbeing throughout pregnancy.
- Optimize your diet.
A healthy nutrition plan can help to keep hormones balanced, so choose nutrient-rich foods that nourish your body. Most pregnant women will feel their best when they eat something every two to three hours, with a focus on protein, healthy fats, and complex carbohydrates. (Psst: These are the best foods to eat during your first trimester.)
Be sure to supplement with a prenatal supplement designed to address your needs at each stage of pregnancy and postpartum recovery.
- Prioritize sleep.
Getting a restful night’s sleep can be difficult during pregnancy, especially as your bump grows. But lack of sleep can wreak havoc on your mood, your appetite, and your energy level—and it may even raise your risk of certain complications, like gestational diabetes and preeclampsia.13 Aim for at least eight hours per night, and take naps during the day if needed.
- Move your body (as long as your OB gives you the green light).
Making time for exercise throughout your pregnancy can be a great way to process stress, relieve anxiety, and balance hormones. Even gentle movement like walking, yoga, swimming, and stretching will do the trick—but if you’re used to a more intense workout routine, talk to your doctor about what’s safe for you. (And don’t skip your rest days!)
Next up: How to manage mood swings, according to a naturopathic doctor, plus 30+ ingredients to avoid during pregnancy.
References:
- Cleveland Clinic: Pregnancy Tests
- American Pregnancy Association: What are HCG levels?
- Endocrine Society: Reproductive Hormones
- What to Expect: Your Guide to Pregnancy Hormones
- Cleveland Clinic: Relaxin
- Cleveland Clinic: Human Placental Lactogen
- Cleveland Clinic: Placenta
- Cleveland Clinic: Prolactin
- My Health Alberta: Oxytocin
- Cleveland Clinic: Oxytocin
- National Partnership for Women & Families: The Role of Hormones in Childbirth
- March of Dimes: Baby blues after pregnancy
- Sleep Foundation: Pregnancy & Sleep
This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and we recommend that you always consult with your healthcare provider. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of Perelel.
