Pain in Labour: Your Hormones Are Your Helpers

Photography: Brandi Johnson

By Dr Sarah J Buckley

Imagine this. Your cat is pregnant, due to give birth around the same time as you are. You have your bags packed for hospital, and are awaiting the first signs of labour with excitement and a little nervousness.

Meanwhile your cat has been hunting for an out-of-the way place: your socks drawer or laundry basket – where she is unlikely to be disturbed. When you notice, you open the wardrobe door, but she moves again. Intrigued, you notice that your observation – even your presence – seems to disturb the whole process. And, wish as you might to get a glimpse into the mysteries of birth before it is your turn, you wake up the next morning to find her washing her four newborn kittens in the linen cupboard.

Why does birth seem so easy to our animal friends when it is so difficult for us? One obvious difference is the altered shape of the pelvis and birth outlet that is caused by our upright stance; our babies need to twist and turn to navigate these unique bends. Even our nearest cousins, the great apes, have a near-straight birth canal.

However, in every other way, human birth is like that of other mammals – those animals that suckle their young – and involves the same hormones – the body’s chemical messengers. These hormones, which originate in one of the oldest parts of our brain, cause the physical processes of labour and birth, as well as exerting a powerful influence on our emotions and behaviour.

Researchers such as French surgeon and natural birth pioneer Michel Odent believe that if we can be more respectful of our mammalian roots, and the hormones that we share, we can have more chance of a straightforward birth ourselves.

Labour and birth involve peak levels of the hormones oxytocin, sometimes called the hormone of love, and prolactin – the mothering hormone, both well-known for their role in breastfeeding. As well as these, beta-endorphin, the body’s natural pain-killer, and the fight-or-flight hormones adrenaline and noradrenaline play an important part in the birth process. There are many more hormonal influences on birth that are not well understood.

All mammals seek a safe place to give birth. This “nesting” instinct may be due to an increase in levels of prolactin, which is sometimes referred to as the nesting hormone. At this stage, as you may have observed with your cat, interference with the nest – or more importantly with the feeling of safety – will stall the beginning of labour.

Even after labour has started, there are certain conditions that will slow, or even stop the process. If the fight-or-flight hormones are activated by feelings of anxiety or fear, contractions will slow down. Our mammalian bodies are designed to give birth in the wilds, where it is an advantage to postpone labour when there is danger, and to seek safety.

Even after labour has started, there are certain conditions that will slow, or even stop the process. If the fight-or-flight hormones are activated by feelings of anxiety or fear, contractions will slow down.

Many women have had the experience of their labour stopping when they entered the unfamiliar surroundings of a hospital, and some women can be as sensitive as a cat to the presence of an observer. Giving birth away from our natural environment can cause the sorts of difficulties for us that captive animals experience when giving birth in a zoo.

Even hunger, which also causes the body to release fight-or-flight hormones, can stop labour from progressing. It makes sense, therefore, for women to eat if they are hungry in the earliest stages of labour. Unfortunately many hospitals have a policy that prevents labouring women from eating once they are admitted.

Oxytocin is the hormone that causes the uterus to contract during labour. Levels of oxytocin increase throughout labour, and are highest around the time of birth, when it contributes to the euphoria that a mother usually feels after an unmedicated birth, and to her receptiveness to her baby. This peak, which is triggered by sensations of stretching of the birth canal as the baby is born, does not occur when an epidural is in place. Administration of an epidural has been found to interfere with bonding between ewes and their newborn lambs by interfering with the oxytocin system.

Synthetic oxytocin is often given by drip – that is, directly into the bloodstream – when labour contractions are inefficient. Oxytocin given in this way does not enter the brain, and so does not contribute to the post-birth “high”, and in fact can interfere with a mothers own oxytocin system. Nipple stimulation is sometimes used to stimulate contractions because, like breastfeeding, this causes oxytocin levels to naturally increase.

Oxytocin has another crucial role to play after the birth. Oxytocin causes the contractions that lead to separation of the placenta from the uterus, and its release as the “after-birth”. When oxytocin levels are high, strong contractions occur that reduce the chance of bleeding, or post-partum haemorrhage.

Putting your newborn baby to your breast is the easiest way to increase oxytocin levels, but privacy is also very important during the hour following birth. This gives the opportunity for uninterrupted skin-to-skin and eye-to-eye contact between mother and baby – conditions that optimise oxytocin release.

Oxytocin helps us in our emotional, as well as our physical, transition to motherhood. Oxytocin contributes to the glow of new motherhood, giving us calm, connected feelings with our baby and those around us. Oxytocin also optimizes digestion and has a generally beneficial effect on other bodily processes: ideal for a breastfeeding mother.

Putting your newborn baby to your breast is the easiest way to increase oxytocin levels, but privacy is also very important during the hour following birth. This gives the opportunity for uninterrupted skin-to-skin and eye-to-eye contact between mother and baby – conditions that optimise oxytocin release.

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