hormones in pregnancy and birth

Hormones in Pregnancy and Birth

Throughout pregnancy, hormones are produced by your placenta, endocrine glands, and brain. These hormones, in their hundreds, enter your bloodstream and body tissues and play a vital role in managing pregnancy and the growth of your baby.

Oestrogen and Progesterone

The corpus luteum and the placenta produce oestrogen and progesterone which are secreted into your bloodstream more more each trimester. They prepare your body to house the growing baby and to make it ready for birth by relaxing the muscles of the uterus, digestive tract and bladder.

hormones in pregnancy and birthThey also make your body more subtle by increasing the flexibility of your joints and ligaments, and also help to change the abdominal muscles and expand the pelvic area ready for labour. Oestrogen and Progesterone play a bigger role in influencing your psychological state and can profoundly affect your emotions. You may experience quite severe mood swings at the onset of pregnancy , through to childbirth and beyond. Some women can suffer from fluid retention, varicose veins and constipation as a result of the increase in the production of oestrogen and progesterone.

How Hormones Regulate Pregnancy and Birth

There are various hormones produced by the fetus, placenta and the mother, that govern the progress of pregnancy and the timing of labour and birth. Following birth, these hormones promote the production of milk and also affect your brain, producing intense feelings of desire for your baby and stimulating the mothering instinct. Some of these hormones are:

Endorphins – Happy and Carefree

These hormones work in conjunction with each other to regulate the functioning of your digestive system, heart, blood pressure and uterine activity. They are part of your autonomic nervous system. They affect your emotional state and and mood. Also known as happy hormones, endorphins suppress pain and can make you feel relaxed.

It is possible to elevate the levels of these happy hormones through activities such as yoga, gentle exercise, massage and anything else that naturally makes you feel relaxed. As pregnancy progresses so does the production of endorphins, all the way up to labour when they are at their highest levels. Their soothing effect and pain killing properties are most needed at this time, and both you and your baby produce endorphins even during birth. If you have a good hormonal balance, and actively work on your health and fitness through diet and exercise, then you should have high levels of iendorphins and experience an elevated mood, sensations of happiness, and even laughter throughout your pregnancy.

Adrenalin – Fight or Flight

Towards the end of labour, adrenalin is released in greater quantities and results in the foetal ejection reflex while you bear down during childbirth. You can have increased levels of adrenalin throughout pregnancy, but the increased production mainly kicks in close to birth.


This hormone is made in the placenta. As its name suggests, it has a softening effect on your joints, ligaments and connective tissues. It increases the flexibility of your spine and pelvis, and plays a role in the preparation of your cervix for birth by ripening and softening it.

Oxytocin – The Love Hormone

This is produced in the pituitary glands by both you and your unborn child. Oxytocin has been called the love hormone, and it works in unison with endorphins to regulate the timing of labour and contractions. The healthier and more relaxed you feel within yourself, the more of this hormone is produced. It has many effects on your emotional state. One of the chief benefits is that it promotes your mothering instinct and can actually make you look forward to giving birth rather than being anxious about it. It works prior to and after birth by continuing to promote these feelings of well being and nurturing. Oxytocin is also released during sexual intercourse and orgasm, and can produce an intense desire to bond with your baby.


This is the hormone that is released during breastfeeding and works in conjunction with oestrogen and progesterone to affect your whole body including your brain. These hormones get together and greatly stimulate your mothering instincts.


These hormones are released at the beginning of labour and are responsible for powerful contractions in the uterus. Hormones produced by your baby’s brain and the placenta stimulate the lining of your uterus which then produces prostaglandins.


This is produced by the adrenal glands. It has many purposes throughout the body and can work as a defence hormone, reducing the sensitivity to allergic substances and minimising the frequency and severity of asthma attacks during pregnancy. It also seems to promotes better skin and can reduce eczema.

Hormones After Birth

Following childbirth there is a huge change in your hormonal profile. The production of oestrogen and progesterone rapidly fall within 48 hours of giving birth, dropping back to their pre-pregnant levels. This sudden change in hormones can produce what is known as the third day blues in some women. On the positive side, the happy hormones such as Oxytocin are still present and being produced in large quantities. This should offset any low moods you may experience after a few days, by promoting feelings of calmness. You can increase the production of the happy hormones through breastfeeding and close contact with your baby.

Prolactin is the hormone responsible for stimulating the flow and production of breast milk. It also plays a role in regulating the menstrual cycle. However, during breastfeeding, the levels are so high that it actually suppresses ovulation and it works as a contraceptive. Again, this hormone’s production can be stimulated by close skin to skin contact with your baby.