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Hormones of labour: what are they and how to promote them PT2

Following on from my last blog post, I want to continue talking about the hormones of labour and how to help promote them. We are constantly talking about and encouraging a physiological, uninterrupted birth if it is medically safe to do. I strongly believe that we need to understand birth physiology, to then know how to promote it or what may hinder it.


Many know this hormone as the milk maker or the mothering hormone. Prolactin promotes milk production after birth but also is active during labour and pregnancy. The levels of prolactin begin to rise during pregnancy, with the expecting arrival of a babe to feed, by 10-20 times. If a woman breastfeeds her baby, this will continue to rise.

Animal studies have shown that the late-pregnancy peak of prolactin production is to promote the formation of the prolactin receptors in the brain and mammary glands. It is also shown that there is prolactin within the amniotic sac and therefore within the fetus's lungs. A near-birth peak of prolactin is likely due to peaks of beta-endorphins and oxytocin*, and in addition, the release of prolactin, in turn, stimulates oxytocin production. Outside of the pregnancy and birth realm, Prolactin is a stress response hormone.

I am forever in awe of how perfectly this process unfolds without our conscious knowing!

It is important that breastfeeding is initiated within the first hour of birth and early and frequent feeds are carried out. This may also contribute to Prolactin receptor formation and therefore the success of breastfeeding particularly. As Prolactin is released during these early feeds, it is possible it helps with maternal adaptations (the mothering hormone), such as reduced anxiety, reduced aggression and reduced muscle tension. It is also associated with increased social desirability, which may help the mother to prioritise infant care*.

As Prolactin is a stress response hormone, it is said that if excessive stress is experienced throughout labour, reduced secretion of Prolactin may occur and therefore affect breastfeeding initiation and the mother and child's journey of breastfeeding.

If a scheduled Caesarean occurs, mothers may miss pre-labour prolactin elevation, the late labour peak or the immediate postpartum increases which will affect their ability or ease to begin breastfeeding.

When looking at promoting Prolactin, I strongly urge mothers and partners to get involved in Amberley Harris's courses and information. Also, known as Maternal Instincts, she has a strong understanding that demand equals supply. Therefore, feed when it is demanded of you (it may be often or irregularly in the first few weeks) to help establish a strong supply.

With augmented labour, the natural production of Prolactin will be impacted. It is important to understand this when making decisions either before, during or after the birth. Encourage your support team to be on board with educating themselves on these hormones so they can also understand the implications and be able to advocate for you in this space.


Ever wondered why so many women begin labour at 1 AM in the morning? Dear, sweet Melatonin, our sleep hormone. I recall a colleague once explaining her experience falling asleep as the Melatonin kicks in: "it's like a blind is slowly coming down and my body slowly relaxes and shuts off". It is through low or no light that our Melatonin is released, and peaks at around 3am.

Melatonin helps a woman become deeply relaxed and be able to disengage the neocortex, our rational thinking brain. It also works alongside Oxytocin to create strong, effective contractions.

Ways to promote:

- Darkness! Pretty self-explanatory right?

- Use an eye mask or sheet over you while labouring if it is too light to create darkness

- Visualisation, breathing and hypnosis (hypnobirthing) tracks can also promote Melatonin


Understood as having an effective role in the onset of labour, Prostaglandins release to get the cervix to begin effacing and dilating. It is through tissue rather than glands (such as the pituitary gland) that Prostaglandins are released. Prostaglandins are actually produced by almost every tissue in the body and serve as important messengers for a variety of functions. Well known to be present in sperm, this is the reason why so many may recommend sex as an induction method.

Through the release of Prostaglandins, the uterus moves into a contractile state, and as said above, initiates the onset of labour.

Prostaglandin gel is a popular and well-known form of induction, and prostaglandin synthase inhibitors are used as a preventative for preterm labour.

When we are looking at ways to promote Prostaglandin production, we are most likely looking more for ways to allow the natural onset of labour. Many people look at natural vs medical forms of inducing or 'nudging along' labour, and yes, even eating dates, drinking raspberry leaf tea and having sex is a form of 'induction' (though none are scientifically proven to work).

To promote the natural onset of labour, think more about your environment and whether you are under internal stress. If you are in an unfavourable environment, you will not be relaxed or comfortable enough for your body to initiate labour and become vulnerable. When we are trying to force our body into labour, whether it is by natural means or medical induction, we are stressing or concerning ourselves with whether it is working, what kind of labour it will create and how we will react.

It's so much easier said than done, but if you can distract yourself, find ways to relax and trust the process of when your baby and body are ready for labour, it will help all these hormones do their job in their own way and own time.


A hormone present in all of our bodies, however, increased in the early months of pregnancy. It is through the lining of the uterus and the placenta that Relaxin is released.

Relaxins' role is to help soften the cervix, release membranes and also soften the ligaments and joints of the pelvis. This helps increase movement and flexibility during pregnancy and labour. As your belly continues to grow, it softens your abdominal muscles to allow this growth, as well as all pelvic floor muscles as the baby moves, grows, gets into position and descends.

When we are looking at the birth process, it is imperative that the body is relaxed enough to allow the change in movements and the opening of the body as the baby moves down. Looking specifically at the perineum and its ability to stretch, Relaxin is a main player in its ability to do so.

If the body experiences an overproduction of Relaxin, a condition known as Symphysis Pubis Dysfunction (SPD) may occur and cause sharp, stabbing pain in the groin.

It is not necessary for women to concern themselves with the levels of Relaxin produced, unless an over or under production occurs, which will lead to obvious signs that can be managed via your health care providers.


The way our bodies know what to do, how to do it and when they do it will never cease to amaze me. The main takeaway that I want you to get from these two posts is that your body has inbuilt systems to support the process of pregnancy, birth and postpartum. It is not necessary for us to control it, but instead trust it. It is up to us to educate ourselves on these systems and support their flow of them. On top of that, you can never go wrong by:

  • Making sure the woman birthing is safe, supported, encouraged and listened to

  • Create a good rapport with the support team and care providers

  • Understand that augmentation, induction, caesarean or opioid relief will alter these hormones - this gap then needs to be addressed to promote optimal healing, bonding, breastfeeding and postpartum experience

  • Learn and incorporate natural pain relief methods

  • Do not separate mother and baby after birth for extended periods of time, or at all if no emergency is present

  • Organising continuous support for labour for both mother and partner as it is highly effective in creating a safe environment

  • Encourage and practice early breastfeeding initiation

I hope you've enjoyed my posts on the hormones of labour. As my knowledge continues to expand, I will refer to and update these resources. The best thing you can do is know your body, connect with her and trust her.

Happy birthing!

* Referenced from Dr Sarah Buckleys , Hormonal Physiology of Childbearing: Evidence and Implications for Women, Babies, and Maternity Care, 2015


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