Although I hate to generalise, our bodies are born with the ability to produce hormones which facilitate birth, not only that but also support the postpartum period and to breast/chest feed, for example. There are, of course, occasions where bodies don’t produce hormones effectively, but moreover when it comes to birth, hormones are inhibited due to the actions of others, specifically health care professionals (HCP) when timing and mode of birth are intervened with.
The workings of our hormones are quite intricate and can not only start labour but also cause it to stall or stop. It is evolutionary. We have the toolkit, but we often impede these through years and years of false scaremongering. Yes, family horror stories and the shit-show that is OBEM.
Our evolutionary toolkit has supported survival (integral to humans) for thousands of years, to prevent us from birthing in unsafe territories, but also in all aspects of the perinatal experience, such as lactation postnatally. Although the element of survival is (should be) much less of an issue, it is important to understand how these hormones work, to support the processes, to enhance the birth process and support the 4th trimester.
Understanding that hormonal physiology is interrelated, coordinated, and mutually regulated between parent and baby helps us to optimise outcomes for both. Although we don’t know explicitly why or how labour starts, we know that our hormones are responsible for the kick start of labour, when our babies are ‘ready’. The relationship is internalised and helps to promote physiological birth and help to improve postnatal attachment. “Disruption of perinatal hormonal physiology may thus impact not only labour and birth, but also breastfeeding and maternal-infant attachment.” S.Buckley, so what are these hormones, and how do they work?
There are 7 main hormones that play a huge role in pregnancy and birth, knowing and understanding their roles can really help you to maximise your body’s physiological response, and create environments that foster their production.
Oxytocin, Prolactin, Adrenaline (catecholamines), Endorphins, Relaxin, Melatonin and Prostaglandins (we’ll investigate each of these in detail soon).
What are the main roles or hormones?
Getting your body ready to give birth (relaxin, prostaglandin, melatonin, oxytocin)
Starting your labour contractions (prostaglandin, oxytocin, endorphins)
Preparing your baby for labour and life outside your body (relaxin, prolactin)
Telling your breasts to make milk and getting your baby ready to breastfeed (prolactin)
Stalling birth and alerting body for transition (catecholamines/adrenaline)
So, let’s break them down…
Oxytocin is one of our primary hormones. It is known as the shy hormone of love. It is produced on several occasions, including during orgasm, laughing, touch and during birth, its primary role is to stimulate contractions. Receptors are found in the uterus which cause the muscles to contract. In doing so, they pull up, causing the cervix to dilate, and builds the fundus at the top of the uterus. This is then what pushes the baby out. Once the baby is out, oxytocin is also responsible for birthing the placenta and limiting the blood loss through retraction of the uterus.
Oxytocin is inhibited by bright lights, observation, intervention including induction and epidural anaesthesia to name a few. When oxytocin levels are reduced (usually caused by adrenaline), labour can stall or even stop, so it is important to know how to maximise the oxytocin levels, these include, touch, feeling safe, relaxed, unobserved, using low lighting and laughter (amongst others). The release of oxytocin also helps to build up endorphins, our own bodies natural pain killer. It is said to be 200x more powerful than morphine. We can bank up endorphins too, through light touch massage, soothing the central nervous system, use of water and with the use of a TENS machine, great for labour and helping us reduce the need for pharmaceutical options which can hinder the natural flow of our hormones.
Oxytocin is also impacted by/works together with other hormones, these include prolactin, melatonin, and prostaglandin. The interrelationship between birth hormones is integral in the physiology of birth and the whole perinatal period. Take prostaglandin, this hormone is responsible for softening the cervix and encouraging the initiation of contractions. This is one of the first steps of the birth process, where the contractions draw up the muscles in the uterus which help to dilate the cervix. The perfect design. Alongside this, melatonin receptors are found in the walls of the uterus, when there is low lighting, melatonin is released and this is thought to help trigger the release of oxytocin, which could be a reason that labours often start at night. In relation to evolution, this makes sense, less threat of danger at night, right? And we know bright lights inhibit oxytocin, so another factor in how understanding melatonin can help the birth process. Prolactin, known as the ‘parenting hormone’ builds throughout pregnancy and peaks during birth, alongside oxytocin. Its primary role is in helping produce breast/chest milk, as well as helping parents adjust to their new role, supporting a new-born’s life outside the uterus.
Adrenaline is the hormone that impacts birth most, in a negative way. It is our fight or flight response and is produced when we feel threatened, usually in birth because we’re fearful/in pain. Adrenaline can stall or stop birth all together and is greatly affected by the environment we are in. Seeking safety, knowing about the birth process, birth rights and having someone to support/advocate for you can really help you to minimise the impact adrenaline can have. Adrenaline does have one positive impact when we are in the ‘transition’ phase, where it helps us to ‘wake up’ and supports the physiological process of the ‘fetal ejection reflex’. This is usually a natural response, and when other hormones are optimal, the rise in adrenaline shouldn’t cause a delay in birth, often in fact, it is the opposite!
Unfortunately, there are many aspects which inhibit our natural production of birth hormones, which are not what we want or need during the perinatal period. Most of these are avoidable, but many are perpetuated by the media and our HCP when information shared is either biased or simply untrue. Thus, creating fear, or a belief that we are unable to birth without support for external factors. One of the biggest barriers to our birthing hormones.