The important hormones of childbirth
Giving birth is controlled by the most primitive part of our brain, sometimes called ‘the reptilian brain’. It controls our basic functions: breathing, heart rate, body temperature, digestion, excretion – and giving birth. It is also where our fight or flight response is controlled.
In normal daily life, especially when at rest, our heart rate is normal, breathing is normal, digestive functions and all the rest are normal. When we encounter stress our body prepares for fight or flight. Our heart rate increases, we start to sweat, blood is diverted to our muscles and non-essential processes such as digestion and excretion shut or slow down. I am sure we can all think of times when we were under stress which made it difficult to eat or go to the loo - for example being in a strange place or insanitary conditions such as a festival. Or becoming relaxed and everything's suddenly working: for example, arriving home from holiday the body relaxes and suddenly we need a poo!
Giving birth is similarly affected. We see this in wild animals – if they are disturbed or feel threatened in labour, labour stops until they feel safe again. Biologically this makes sense as it ensures both mother and baby survive. Interestingly, with animals in advanced labour who are threatened labour speeds up to get the baby out quickly so they can then get to safety.
Birth is affected by three main hormones associated with the autonomic nervous system: oxytocin, endorphins and adrenaline.
Oxytocin is like the accelerator of labour. The more oxytocin your body releases the stronger and closer the surges/contractions/waves of power become. (I like to call contractions 'waves of power' because that is what it feels like.) Oxytocin is also known as the love hormone as it is released during cuddles, stroking, kissing, nipple stimulation and sex. The release of oxytocin is inhibited by the activation of the sympathetic system due to fear or embarrassment, and also by bright lights.
Oxytocin causes the muscles to contract. During sexual climax it is oxytocin that causes ejaculation and vaginal contractions. Oxytocin makes your heart muscles contract when you look with love at someone or something. During breastfeeding it makes the tiny slithers of muscle around each milk cell in the breasts contract to release the milk. In labour it makes the uterus muscles contract. In the first stage of labour the muscles pull the cervix open, and in the second stage of labour they push the baby down. You can read more about your amazing uterus here.
Dark is important too for another hormone: melatonin. Only recently scientists have found that melatonin increases the amount of oxytocin, which is why more babies are born at night! It works with the oxytocin to increase production, and increase the power of the surges/waves of power.
Endorphins are the body’s natural pain relief, a natural opiate. They are released when we are happy and feel loved, when we are massaged or we rub a part of our body to ease a pain. They are also released when we laugh. Their release is inhibited in the same ways as oxytocin.
Where oxytocin was the accelerator, endorphins are the clutch. As oxytocin is released and contractions increase, the body releases endorphins which help you cope with the waves of power. This then leads to more oxytocin being released, waves increase in strength and length as labour goes up a gear. So it goes on: oxytocin is released, waves increase, endorphins are released, the body copes, more oxytocin is released, waves increase, endorphins are released, the body copes etc. Women find themselves in 'labour land'. As the oxytocin and endorphins flow, the reptilian part of the brain is fully in control, and you become almost non-verbal, and less aware of time.
By contrast, when a woman has an epidural the body doesn't need so much endorphins so they drop away, and then so does the level of oxytocin, causing labour to drop down a gear. It is one of the reasons that having an epidural can result in a longer labour.
By the end of labour the cocktail of oxytocin and endorphins creates a natural high. Davina McColl, the presenter, who confesses to using drugs in her past, described the high at the point of birth as the biggest high she had ever experienced. Both mother and baby’s brains are flooded which aids bonding, the contraction of the uterus and breastfeeding.
Women who have epidurals, or caesarean births, are induced, or who feel a lot of stress during the birth may find they don't get that instant sense of love and bonding, because they don't have high levels of endorphins and oxytocin in their brain. It can take a little while, even months, to fall in love with their baby. If this is you, give yourself time and don't be hard on yourself.
Adrenaline is the brake in this analogy. The release of adrenaline causes labour to slow down or stop. When adrenaline is released, oxytocin and endorphins drop away. Adrenaline is released when we are afraid, embarrassed, feel lack of control. Remember what happens to other mammals in labour? This happens to women too. It is very common for women who have been labouring well at home to find that their waves slow or stop when they go to hospital as the adrenaline released by the excitement and anxiety. Once they get settled in their room and start to relax and adrenaline reduces, the waves return.
Your brain is more likely to release adrenaline if the reptilian brain senses danger, even if you think you feel safe. Use sensory input to reassure your reptilian brain. One client took her partner's pillow as it smelt of him and helped her to feel safe. Smells, sounds, touch such as massage, affirmation, quiet voices, can all help to reduce the adrenaline, and bring back oxytocin and endorphins.
Partners play a central role in helping you to feel safe and reduce the adrenaline. A second birth partner, or doula, can support your partner to reduce their stress, so they can reassure you, and a doula or second birth partner can help you feel safer.
Just to complete the analogy: the handbrake in labour is stimulation on the neocortex. The neocortex or fore brain is the most recent part of the brain and controls language and reason. In labour the more primitive part of the brain is in control and there is little activity in the neocortex. Stimulation of the neocortex by talking, or making decisions, wakes up the neocortex which then takes over control of the body resulting in stalled labour. Left undisturbed, women are in ‘labour land’, barely able to talk by the end, or understand speech.
Let the hormones flow
So turn off the lights, have a cuddle, create your space, take in your own pillows that have your smell. In order for birth hormones to flow the subconscious mind needs to feel safe. It doesn't matter if our thinking brain says it's safe, it is all about the subconscious.
Relaxation techniques and visualisation, such as with hypnobirthing, help to reduce adrenaline and let oxytocin and endorphins flow.
Humans need to feel safe as much as any animal. Where do cats go to give birth? Somewhere dark, quiet, warm, and undisturbed.
I hope this has helped you to understand how labour is driven by the hormones of birth, and how your can help your labour go as smoothly as possible. Do ask me any questions.
I am a doula and childbirth educator. I help parents and parents-to-be to find and follow their own path through pregnancy, birth, and parenthood.
The next step is to learn how to ride the waves of power. Check out my Birth Dreaming e-course.