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Hormones play a big role when it comes to pregnancy and birth. Here we explore what they do and why.

Hormones, labour and birth: an introduction

You know your hormones are going to be working hard at this time but you might not know exactly what they’re doing. You’ll in fact have four major hormonal systems active when you’re in labour and giving birth. These hormones are:

  • oxytocin (the love hormone)
  • beta-endorphins (the hormones of pleasure and transcendence)
  • epinephrine and norepinephrine (the hormones of excitement)
  • prolactin (the mothering hormone).

(Buckley, 2002)

Here’s what impact all four will have on you…

Oxytocin or the love hormone

Oxytocin is the love hormone, which is why it’s released during sex, orgasm, birth and breastfeeding (Odent, 1999; Buckley, 2002).

Oxytocin will make you feel more affectionate and selfless, and its main function in labour is to bring on contractions (Dawood et al, 1978). You’ll get a surge of oxytocin in the final stage, so if you’re having a vaginal birth it will help you along with pushing.

Oxytocin reduces stress, calms you down and helps with pain during labour (Buckley, 2015). Impressively, your baby will also produce oxytocin before and during labour (Chard et al, 1971).  

Oxytocin hangs around after birth too, helping you feel more relaxed, well-nourished and bonded with your baby (Buckley 2002, Buckley 2015). It helps with the let-down reflex during breastfeeding and protects you against postpartum haemorrhage (Buckley, 2002).

Beta-endorphins or the pleasure hormones

Endorphins are naturally occurring opiates, similar to morphine and heroin. Like oxytocin, they mostly appear during sex, pregnancy, birth and breastfeeding. Beta-endorphins reduce pain and suppress the immune system, which is important so that it doesn’t act ‘against’ your baby (Buckley, 2002, 2015).

If you’re stressed during labour, that can make you release excessive beta-endorphins, which may inhibit oxytocin and slow things down (Buckley 2015). That’s why keeping things as calm as possible is a great thing in labour.

Beta-endorphin also helps with the release of prolactin during labour, preparing your breasts for feeding (Rivier et al, 1976).

And one more thing: it helps in the final phase of your baby’s developing lungs too (Buckley 2015).

Epinephrine and norepinephrine or fight or flight hormones

You might have heard these two referred to as fight-or-flight hormones but their proper names are epinephrine and norepinephrine (adrenaline and noradrenaline). They are produced during stresses like fright, anxiety, hunger or cold and also when you’re excited (Buckley 2015).

You’re likely to get a high level of these hormones if you don’t feel private, calm, safe and undisturbed and they can then inhibit oxytocin (Buckley 2015). Yet in the late-labour stage if you perceive danger or stress, they may paradoxically stimulate contractions so you give birth more quickly (Buckley 2015).  

A rise in epinephrine when you’re in the later stages of labour increases your levels of prostaglandin and cortisol to help with contractions. This will make you feel a sudden rush of energy and will cause several strong contractions and will help you push (Buckley, 2002, 2015).

These hormones help your baby too by protecting them against a lack of oxygen (Buckley, 2002). Your baby will have high levels of these hormones during birth but they’ll drop quickly once you sooth them afterwards (Lagercrantz and Bistoletti 1977; Buckley, 2002).

Prolactin or the mothering hormone

Prolactin is the mothering hormone. And it's the major hormone for breastfeeding.

Prolactin starts to increase during pregnancy and peaks at birth (Buckley, 2002). Your baby produces prolactin in the womb too (Daniels and Martin, 1994)

Hormones and your feelings after birth

Lots of women get the baby blues during the first week after birth of her baby days (NHS Choices, 2018). You might feel down or depressed, emotional or irritated and likely to burst into tears at any second.

Don't despair though: these symptoms are totally normal. They’re due to the sudden hormonal and chemical changes that happen after you give birth.

If you feel like you are suffering from something more extreme and it isn’t going away though, talk to your GP or midwife. You might be suffering from postnatal depression and should get some support or help right away.

Further information 

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700.

We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.

Buckley SJ. (2015) Hormonal physiology of childbearing: Evidence and implications for women, babies, and maternity care. Washington, D.C.: Childbirth Connection Programs, National Partnership for Women and Families. Available from: http://www.nationalpartnership.org/research-library/maternal-health/hor… [Accessed 25th April 2018]

Buckley SJ. (2002) Ecstatic birth: The hormonal blueprint of labor. Available from: http://www.dancingstarbirth.ca/Handouts/Ecstatic_Birth.pdf [Accessed 25th April 2018]

Chard T, Hudson CN, Edwards CR, Boyd NR. (1971)Release of oxytocin and vasopressin by the human fetus during labour. Nature. 234:352-354. Available from: https://www.ncbi.nlm.nih.gov/pubmed/4944487 [Accessed 25th April 2018]

Daniels G,  Martin J. (1994) Neuroendocrine regulation and diseases of the anterior pituitary and hypothalamus, In Harrison’s Principles of Internal Medicine, 13th edition. New York: McGraw- Hill. [Accessed 25th April 2018]

Dawood MY, Raghavan KS, Pociask C, Fuchs F. (1978) Oxytocin in human pregnancy and partrurition. Obstetrics and Gynecology. 1978; (51):138-143. Available from: https://www.ncbi.nlm.nih.gov/pubmed/622223 [Accessed 25th April 2018]
Lagercrantz H and Bistoletti H. (1977) Catecholamine release in the newborn infant at birth. Pediatric Research. 8:889-893. Available from: https://www.ncbi.nlm.nih.gov/pubmed/887309 [Accessed 25th April 2018]

NHS Choices. (2018) Feeling depressed after childbirth. Available from: https://www.nhs.uk/conditions/pregnancy-and-baby/feeling-depressed-afte… [Accessed 25th April 2018]

Odent M. (1999) The Scientification of Love. London. Free Association Press.

Rivier C, Vale W, Ling N, Brown M, Guillemin R.(1976) Stimulation in vivo of the secretion of prolactin and growth hormone by beta-endorphin. Endocrinology. 100:238-241. Available from: https://www.ncbi.nlm.nih.gov/pubmed/187406 [Accessed 25th April 2018]

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