What are the main pregnancy hormones?
Hormones play a major role in your pregnancy – they prepare your body for labor and breastfeeding and help your baby develop. Some hormone surges don't have an obvious effect that you can feel, but others – such as those related to morning sickness or milk production in the breasts – will be very apparent. Here are the dominant players in your hormone mix when you're pregnant.
hCG
Under normal circumstances, human chorionic gonadotropin hormone (hCG) is made only during pregnancy, which is why home pregnancy tests are designed to detect this hormone. Your body makes hCG once a fertilized egg attaches along the uterine wall, about six days after fertilization, and the hormone continues to be produced during pregnancy. It rises the most in the first trimester, and may play a role in the nausea and vomiting associated with morning sickness.
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hPL
Human placental lactogen (hPL), sometimes called human chorionic somatomammotropin, is made by the placenta and helps regulate your metabolism and glucose levels so that your baby is able to get the proper nutrients. As your baby grows, this hormone rises in response. It usually peaks around 34 weeks and is also associated with stimulation of milk glands in the third trimester as your body prepares for breastfeeding.
Estrogen
Normally made in the ovaries, estrogen is produced by the placenta during pregnancy. That leads to a higher concentration of estrogen while you're pregnant than you would have otherwise. The hormone peaks in the first trimester but is elevated throughout pregnancy to help your baby grow and to increase blood flow to the uterus. In addition to hCG, estrogen may also lead to nausea in the first trimester.
Progesterone
Made by the ovaries and placenta during pregnancy, progesterone increases significantly during the first trimester and then levels out for the second and third trimesters. The hormone thickens the uterine lining for better implantation of the fertilized egg and increases blood flow to the uterus. If you're having heartburn or gas and constipation, progesterone may be partly responsible.
FSH
Follicle-stimulating hormone (FSH) is secreted by the pituitary gland, and its main function is to stimulate the ovaries so they produce eggs that can be fertilized. Although it aids in preparing the placenta in the first trimester, it drops below non-pregnancy levels after that and remains relatively low throughout your pregnancy.
LH
Also produced in the pituitary gland, luteinizing hormone (LH) is key for regulating your menstrual cycle. When estrogen rises and FSH lowers, your body will start making more LH. That's what causes an egg to be released from the ovary during ovulation. Once the egg is fertilized and implanted, LH levels decrease, similar to the drop in FSH levels.
Prolactin
Another pituitary gland-created hormone, prolactin, causes breast growth and milk production, especially in the third trimester, and can be related to breast tenderness as your mammary glands develop. During the first trimester, the milk ducts in your breasts expand and the fatty tissue diminishes. After delivery, prolactin causes milk to be released during breastfeeding (with the help of decreasing estrogen and progesterone levels).
Relaxin
Produced by the ovaries and placenta, relaxin softens and widens the cervix and relaxes the ligaments in the pelvis to prepare the body for delivery. The hormone's level is highest in the first trimester, when it helps prevent contractions in the uterine wall so the fertilized egg can implant properly. During pregnancy, relaxin helps regulate your cardiovascular system as it adjusts to an increased demand for oxygen.
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Oxytocin
A chemical messenger between the brain and your organs, oxytocin is responsible for the contraction of the uterus during labor and breastfeeding. You may be given a manufactured version of oxytocin, Pitocin or Syntocinon, to strengthen and increase the frequency of contractions during labor. In addition to helping milk move through the breast ducts, oxytocin also prompts mother-baby bonding.
Other significant pregnancy hormones
Although the hormones listed above are the most dominant, some other hormones may also come into play during your pregnancy. These can include:
- Cortisol: Sometimes called the stress hormone, cortisol tends to increase by two to four times its pre-pregnancy level. Although cortisol does help with fetal development, it's important to manage stress during pregnancy so cortisol levels don't become too elevated.
- Insulin: As pregnancy advances, especially into the third trimester, sensitivity to insulin may become an issue. This is why some women without a history of diabetes develop gestational diabetes.
What will happen to my hormones postpartum?
After you give birth, your hormone levels will change, sometimes dramatically. Most notably, estrogen and progesterone drop almost immediately while oxytocin and prolactin surge. Over the first couple days, oxytocin levels will begin to decrease, which may contribute to mood changes or postpartum depression.
It can take up to six months for hormones to return to pre-pregnancy levels. After six months, prolactin will begin to decline but will continue to help with milk production as long as you're breastfeeding.
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Ways to manage changes in pregnancy hormones
Changes in pregnancy hormones can create issues like nausea, vomiting, mood swings, heartburn, breast tenderness, and fatigue. Some strategies that can help include:
- Doing low-impact exercise that's geared toward pregnancy, such as yoga or swimming
- Getting enough rest by sticking to a bedtime schedule and napping when needed
- Talking to your midwife or doctor about morning sickness and getting treatment
- Discussing your feelings with friends, family, or a supportive online group
- Finding strategies that help you de-stress
When to call your provider about hormonal side effects
Hormone shifts can cause all sorts of side effects both during pregnancy and afterwards.
Signs of a postpartum hormone imbalance can include ongoing depression, anxiety, weight gain, lack of concentration, mood swings, insomnia, and irritability. If these are affecting your quality of life, talk to your pregnancy care provider about them.
You may be dealing with postpartum depression, which doesn't always include sadness or indifference – it could cause anger or fear, for example. It's common to have a dip in mood during your baby's first two weeks, especially with a disrupted sleep schedule, but if you're struggling, talk with your provider.
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