Everything you need to know about pregnancy hormones

Feeling hormonal? Learn more about the cocktail of chemicals your body produces to help support your baby’s growth…


Yep, pregnancy hormones are to blame for your unexpected mood swings, morning sickness, hot flashes, bloatedness and swelling, and even outbreaks on your previously flawless skin.

Hormonal changes may seem like the bane of every expectant mum’s existence, but they are actually essential to a safe and healthy pregnancy.

So, before you go blaming and cursing all your strange symptoms on those darn hormones, find out how these chemical messengers boost your blossoming body.

1. hCG, or human Chorionic Gonadotropin

The first sign of a hormonal change you’ll notice will probably be in the form of the positive sign you see on your pregnancy test stick. Pregnancy test sticks confirm a pregnancy by picking up the presence of the hormone hCG in an expectant mum’s urine. hCG levels in a woman’s blood generally double every two to three days in early pregnancy.

hCG is created by your placenta cells, which then stimulate the production of two other important hormones ― oestrogen and progesterone. Peaking at around 10 to 12 weeks, hCG levels then start to decline in the second trimester, when the placenta takes over the production of oestrogen and progesterone.

 While typical hCG levels can vary, lower or stagnant levels tend to indicate a tendency to miscarry, or may point to an ectopic pregnancy. Still, don’t get too worked up over your hCG numbers ― some perfectly healthy and successful pregnancies have quite low levels of hCG.

hCG levels may be blamed for certain early pregnancy symptoms, like tender breasts and a sensitive bladder (since it’s responsible for increasing the blood supply to your pelvic area). Some believe that it’s linked to the nausea and vomiting mums-to-be experience in the first trimester. 

Pregnancy test sticks confirm a pregnancy by picking up the presence of the hormone hCG in an expectant mum’s urine. 

2. Oestrogen

Oestrogen (along with progesterone) plays a crucial role in your baby’s development during pregnancy. Both these hormones are produced by the corpus luteum, a cyst on the ovary, until around the tenth week, when the placenta takes over.

Oestrogen helps your uterus to grow, increases blood flow around your body, and maintains your uterine lining that keeps bubba safe. It also helps your baby’s little organs to develop, and regulates your baby’s bone density. This hormone is also responsible for your middle-of-the-night cravings, as well as morning sickness.

On the downside, oestrogen can have negative effects on the mum-to-be’s skin ― your skin colour may change, and it can cause spider veins (clusters of tiny blood vessels close to the surface of the skin) in the face and legs. However, if you’re lucky, you may get what people commonly call the “pregnancy glow”.

3. Progesterone

Along with oestrogen, progesterone is a vital hormone that supports your pregnancy. Both work together to suppress further ovulation during pregnancy.

Progesterone performs a number of key functions during pregnancy ― besides helping preventing your immune system from rejecting the embryo (it’s technically a foreign body), it maintains the lining of your uterus.

Progesterone helps your baby to develop, and also softens your ligaments and cartilage to prepare you for labour. It also boosts the growth of breast tissue and milk-producing glands to prepare you for breastfeeding. If your progesterone levels are too low, your gynae may encourage you to take progesterone supplements to support your pregnancy.

The increase in the expectant mum’s progesterone levels may be responsible for her breast tenderness, mood swings, as well as the fatigue many of these women feel.