Pregnancy Hormones: Explained

Pregnancy hormones are blamed for everything during your pregnancy and rightly so as they are the cause of many symptoms such as mood swings, morning sickness and even your new found aversion to some foods you previously loved.

And while many of the changes you’re going through are visible; your bigger breasts and growing tummy being the most obvious, there are others such as tiredness that you can’t see but you can certainly feel. A great number of these changes are due to hormones, powerful chemicals that affect your mind, your body and your pregnancy.

Below we have explained some of main hormones to help give you a better understanding of what exactly is happening to your body during pregnancy.

Human chorionic gonadotropin (hCG)

hCG is the hormone that gets things ready in your womb and placenta for the growth of your little one, and it is also thought to be responsible for morning sickness and overwhelming tiredness that can be felt throughout pregnancy.

It is also the hormone that GPs check in your urine or blood to determine whether you’re pregnant or not.


This hormone serves the very important role of allowing your little one to grow. Progesterone levels increase throughout pregnancy to help maintain the inner layer of the uterus so it can provide support for your developing baby. Would you prefer the good news or not so good news first? While progesterone can cause morning sickness, sore boobs, bloated tummies and skin breakouts, it also helps with stress and promotes sleep.


Oestrogen is the hormone often associated with changes in your mood and sex drive, and it also improves blood flow between the uterus and placenta and prepares your breasts for milk production. It is also the hormone you can blame for the amplification of emotions.


Relaxin does exactly what you’d think- relaxes all the muscles necessary so that your pregnancy can progress and your little one can grow and relaxes your arteries so that you’re blood pressure can be good enough for two. The downside is that things you don’t want relaxed are sometimes affected like the muscle that prevents stomach acid from creeping back into your chest and you get heartburn.


Oxytocin is the more commonly known as the feel good hormone and is very important as it helps us bond with others, strengthening the mother-baby bond that you have with your bump and your newborn after birth.

If you feel like you are going crazy, don’t. Pregnancy hormones play havoc with both your body and your emotions and it is all perfectly normal.