In this article, we're going to discuss pregnancy hormones: everything you need to know.
It's probably true to say that, aside from puberty, your body has never been so mercilessly ravaged by hormones than during pregnancy.
In fact, every single pregnancy symptom - good and not-so-good - can be put down to the hormones swirling around inside you.
Pregnancy hormones: Everything you need to know
These wonderful hormones make your uterus a soft, safe place to grow, make your baby's bones grow, and tell your breasts to start producing milk to nourish your little one.
But they're also responsible for your sporadic sobbing, your sickness, the swelling, pigmentation, constipation, and the pesky brain fog.
Ultimately, they're the reason you can grow a new life, and each plays its own specific role.
So here's everything you need to know about pregnancy and postpartum hormones.
Estrogen
What role does estrogen play in pregnancy?
Along with progesterone, estrogen is one of the two main hormones that get the pregnancy started.
Produced by the ovaries and later by the placenta, estrogen helps the uterus grow, maintains uterine lining, regulates other key hormones and triggers the development of baby’s organs. And when it’s time to breastfeed, estrogen promotes the growth of breast tissue and helps milk flow.
Estrogen is also the reason you might have a stuffy nose, blotchy skin, and hyperpigmentation.
Fun fact: A woman will produce more estrogen during one pregnancy than throughout her entire life when not pregnant.
Progesterone
What role does progesterone play in pregnancy?
Basically, it helps the uterine lining get ready to receive a fertilized egg. But progesterone, along with the hormone relaxin, can cause some issues such as heartburn, indigestion, constipation, and bloating.
Progesterone also teams up with relaxin to help soften ligaments and cartilage, and loosen your joints to prepare you for labor.
And if your gums swell and start to bleed, your skin breaks out or you feel super sweaty, that’s progesterone too.
Human chorionic gonadotropin (hCG)
Human chorionic gonadotropin is a hormone that's only produced during pregnancy. You'll probably first hear of it when it comes to taking a pregnancy test, as this is the chemical that turns your pee stick positive.
What role does hCG play in pregnancy?
This hormone amps up the production of estrogen and progesterone. Early on in pregnancy, hCG levels are low, but they soon rise and double every two days, peaking between weeks 7 and 12 and then falling back at the start of your second trimester.
The placenta later takes over the making of estrogen and progesterone, but hCG never fully goes away.
Follicle stimulating hormone (FSH)
What role does FSH play in pregnancy?
A very important one actually as it's one of the first of a landslide of hormones that's necessary to launch your pregnancy. It's actually present before you even conceive, and it directs the ovaries to make eggs and estrogen.
Luteinizing hormone (LH)
This hormone is made by the pituitary gland and works with FSH to bring on your period.
LH levels rise just before ovulation and trigger the release of an egg from your ovary.
But if you don't become pregnant in a cycle, your hormone levels drop and your period comes.
What role does LH play in pregnancy?
If a sperm and egg come together, the right hormones, including progesterone, will be produced to ripen the uterus and nourish your growing baby.
If you’re struggling to conceive, your doctor may check your LH levels.
When these are higher than normal, ovulation may be impacted or your hormones may be imbalanced on the whole, which is sometimes behind a case of polycystic ovarian syndrome (PCOS).
Human placental lactogen (hPL)
This hormone is made by the placenta and gives nutrition to the fetus. It also stimulates milk glands in the breasts for breastfeeding.
Prolactin
What role does prolactin play in pregnancy?
Also known as the milk hormone, it basically makes your boobs bigger and produces the milk you’ll need to feed your baby after delivery.
Fun fact: Prolactin is also responsible for all that new body hair you get in pregnancy - but it usually disappears around six months postpartum.
Placenta growth factor
You need placental growth factor to boost blood vessel growth which will transport the increased blood volume needed to nourish and support a growing baby.
What role does placenta growth factor play in pregnancy?
Not having enough of this pregnancy hormone may cause blood vessels in the placenta to narrow instead of widen, which can cause high blood pressure and possibly preeclampsia.
Relaxin
Relaxin levels surge after ovulation to help prep the uterine wall for pregnancy. Relaxin levels drop back down until the next cycle if there’s no fertilization that month.
What role does Relaxin play in pregnancy?
As the name hints, Relaxin helps to relax your muscles, bones, ligaments and joints in your pelvis later in pregnancy in preparation for labour.
It also softens and lengthens the cervix.
Oxytocin
What role does oxytocin play in pregnancy?
This muscle-contracting hormone is mostly known for stimulating labour contractions.
And if your labour is slow to progress, you might get a shot of Pitocin, the synthetic version of oxytocin, to help move things along.
Once you’ve delivered, oxytocin helps to shrink the uterus down in size and move milk into the breasts.
Other pregnancy hormones
There are plenty more pregnancy hormones which do all kinds of roles from promoting bone formation and lung growth, to causing swelling and stretch marks.
Postpartum hormones
Giving birth isn't the end of the hormone surges.
Progesterone and estrogen levels drop as soon as your baby arrives, but then other hormones step up to help you become a mom.
Oxytocin, sometimes called the “mothering hormone,” increases, and prolactin is an important post-birth hormone as it encourages the production of breast milk.
The hormone rollercoaster
The surges and decreases in hormones can cause mood swings, distress and baby blues for some moms.
If you feel down or are struggling to cope postpartum, speak to your doctor. Never suffer in silence.
