Everything you need to know about hormones during pregnancy

Posted in Pregnancy Health.

A woman’s body resembles a chaotic episode of The Block as she’s growing her baby, with constant renovations and unforeseen circumstances popping up as the weeks roll out!

Mother’s little helpers

While every pregnancy mood or symptom is attributed to the “hormone” shifts, the truth is that mother’s little helpers deserve mad props! They have some very serious work to do.

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Here’s a few of the main contenders in the helpful pregnancy hormone stakes:

1. Human Chorionic Gonadotropin (HCG)

Where does it come from?

In pregnant women, the placenta triggers the production of HCG.

What does it do?

HCG is thought of as the OG pregnancy hormone, and it’s boosted by the fledgling placenta after conception. Men and women both have small amounts of HCG in their body at all times, but the presence of higher than normal levels of this hormone in an expectant woman’s urine is what sparks that ‘positive’ result in early pregnancy tests. By around the two week mark of pregnancy, the HCG levels will be high enough to give an accurate result, but it can be detected in the bloodstream around seven days from conception.

HCG levels are usually higher in multiple pregnancies – twins or triplets, for example – providing the first indication there is more than one baby on board. This hormone also doubles each day for the first ten weeks or so of pregnancy, and moderates appropriate levels of other pregnancy hormones – like oestrogen and progesterone – until the placenta is developed enough to self-moderate.

HCG is thought to be responsible for morning sickness, and for increasing the blood supply to an expectant mum’s pelvis, making her want to pee almost all of the time.

Side-effects: Frequent urination, morning sickness

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2. Progesterone

Where does it come from? 

Progesterone is secreted from the corpus luteum (in the ovaries), the adrenal glands and, during pregnancy, from the placenta.

What does it do?

Progesterone is the interior decorator of hormones, rearranging a mum-to-be’s body parts so that they’re more accomodating  for her growing bub. Progesterone wants to make sure a woman’s body is soft, flexible, cool, with plenty of blood flowing to all the right places. The perfect place for creating a human, basically!

Progesterone impacts women’s fertility and menstruation, and has the important job of thickening the lining of a woman’s uterus, making it a comfy spot for a fertilised egg to implant. This helpful hormone continues to keep things cushy during pregnancy, and also stimulates the growth of breast tissue, softens cartilage to make room for baby and helps the placenta function.

Progesterone may be accomodating to babies, but it has some pesky side-effects for mums. For starters, it can cause acne, thanks to the way it optimises a woman’s natural cooling system and makes her sweat a whole lot more. This hormone may also cause swollen gums – thanks to progesterone pushing more blood to all body parts, including her mouth. Aching joints are another annoying problem – as this hormone shifts inner bits and loosens everything up. A newly progesterone-relaxed digestive system – think stomach, intestines, bowel – may also mean bloating, heartburn, constipation and indigestion too.

Progesterone also increases fatigue, particularly in that busy first trimester. A pregnant woman might find herself bone-achingly exhausted and forced to slow down. The plus side of this is that her body channels all its energy into tiny human-growing!

This progesterone-induced fatigue may diminish a little, as a woman enters her second trimester, but many mums find they’re knackered all the time. Sorry about that, mums!

Side effects: swollen gums, acne, fatigue, heartburn, indigestion, gas, constipation, aching joints, stuffy nose, mood swings, headaches, sore breasts.

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3. Oestrogen

Where does it come from?

Oestrogen is secreted by the ovaries.

What does it do?

The other super-hardworking pregnancy and postpartum hormone is oestrogen (also known as estrogen). Both men and women have oestrogen in their systems (men have less!) but this hormone really steps up when pregnancy occurs.

Oestrogen appears to be more growth-focused than its accomodating pal progesterone, and its super-powers cleverly extend to the developing baby, too. This hormone is also thought to be responsible for that tell-tale pregnancy glow!

While some of the work oestrogen does is in partnership with progesterone’s clever efforts – think optimising the uterine lining, increasing blood flow to various parts of the body and growing excellent baby-feeding boobs – complete with ready-to-go milk ducts, this hormone works hard on some other things too. Oestrogen helps your baby’s bones and organs develop nicely, for instance. 

It’s thought that oestrogen contributes to morning sickness and that it pushes more blood supply to mucous membranes, causing stuffy and drippy noses in a pregnant mum. 

Oestrogen is also thought to be responsible for pregnancy skin discolourations and hyper pigmentation such as the linea nigra, darkened nipples and the darkened skin that sometimes appears on a woman’s face (known as the “mask of pregnancy”).

Once a woman delivers her baby, her oestrogen levels will drop, often causing hot flashes and increased perspiration. This dip can also cause a woman’s hair to fall out in clumps postpartum too.

Side effects: skin changes, sore breasts, stuffy nose 

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4. Oxytocin

Where does it come from?

Oxytocin is released by the brain’s posterior pituitary gland.

What does it do?

It is often referred to as the ‘love hormone’ and is released during sex, pregnancy, labour and after birth, too. When a woman becomes pregnant, she becomes more sensitive to oxytocin and levels of this hormone increase, which slows her metabolism. Not only does this promote weight gain in an expectant mum, it means this weight provides an energy store for the fast-growing foetus.

This hormone is a real cheerleader, as once labour begins, oxytocin helps contractions along. Oxytocin also helps the cervix to stretch and soften during labour.

When a baby sucks at a mother’s breast, this stimulates oxytocin secretion into the blood, which then causes milk to be let down into the breast. This also causes the uterus to contract, as a woman recovers from the birth.

The feel-good love properties of this hormone encourage bonding with babies – and partners – and its links to the reward centre of our brains mean that the more hugs we give our baby, the more hugs we want to give our baby (or other loved ones!).

Side effects: lots of hugging, uterine contractions, milk production aka leaky boobs.

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5. Relaxin

Where does it come from?

Relaxin is secreted from the corpus luteum (in the ovaries) and also from the placenta.

What does it do?

Another accomodating hormone, relaxin helps ready a woman’s body for childbirth. This hormone increases the flexibility of the symphysis pubis joint and pelvic ligaments.

Relaxin helps to make room for the growing foetus and it also helps the cervix to dilate during labor.

6. Prolactin

Where does it come from?

Prolactin is secreted from the pituitary glands at the base of the brain.

What does it do?

Prolactin is the breastfeeding hormone, increasing dramatically during pregnancy and helping a woman’s breasts to develop so she can feed her baby.

This hormone aids in the production of milk and also has a calming affect when secreted. Or so they say!

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This post was originally published on 18 October 2017


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