Your pregnancy hormones explained

Your emotions seem to be all over the place and you’re pregnant. But what are pregnancy hormones? and how might they affect you?



What does it do? It relaxes the smooth muscle in your womb helps to stimulate breast tissue growth.


This will affect… Pretty much everything! It’s the main reason that you’ll feel tired, and possibly bloated, it’s also responsible for acid reflux, breast tenderness and hip pain.

When does it kick in? At the start of your pregnancy, with it being produced most often before the birth.

How long will it last? Your energy levels should return to normal by your second trimester.

Human Chorionic Gonadotrophin (HCG)

What does it do?  HCG helps to maintain levels of oestrogen and progesterone.

This will affect… Your tummy, it’s the reason you get morning sickness and also makes you need to wee more.

When does it kick in? As soon as you fall pregnant, and it rises during your first 12 weeks of pregnancy.

How long will it last? HCG usually peaks at around weeks 8 to 10, after which you should experience what’s known as that pregnancy ‘bloom’.


What does it do?  Helps the foetus and milk glands develop.

This will affect… Everything! It’s responsible for your flushed ‘pregnancy glow’, it also magnifies your emotions and increases your sense of smell.

When does it kick in? It’s produced by the placenta, so occurs throughout your pregnancy.

How long will it last? The symptoms decrease during the second trimester, and will fall immediately after the birth.


What does it do?  Not only does it start contractions, Oxytocin also starts milk production and induces bonding between you and your newborn.

This will affect… Your contractions and your milk flow.

When does it kick in? When you go into labour.

How long will it last? Only until you give birth, Oxytocin levels fall directly afterwards.


What does it do?  Gets your body ready for breastfeeding.

This will affect… Your breasts and milk production.

When does it kick in? As soon as you fall pregnant, and it’s present throughout your pregnancy.

How long will it last? For two weeks after you’ve given birth your Prolactin levels will remain high. Breastfeeding will further stimulate the production of Prolactin, which lets you lactate and also helps to suppress menstruation.


What does it do?  Relaxin softens the cervix and ligaments, so you can grow!

This will affect…  Your joints

When does it kick in?  Just after ovulation, and peaks during your first trimester.


How long will it last?  Throughout your pregnancy until after you’ve given birth.

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