Living in the Yukon, where the seasonal variations in light are drastic, my patients and I are very aware of the extent to which light exposure affects melatonin concentrations and sleep quality. Melatonin is the biological response to darkness – levels increase at night, and fall during the day. Interestingly, melatonin levels are now understood to affect not only sleep quality, but also the potential to initiate labour for pregnant mothers.
The uterus has melatonin receptors, which explains why spontaneous labour, and delivery, occur most frequently at night. Now, a study published in the Journal of Pineal Research has shown a positive relationship between melatonin concentrations and uterine contractions in women after 35 weeks of pregnancy. The study indicated decreasing contraction rates with decreased melatonin levels from light exposure, and increased contraction rates with increased melatonin levels from uninterrupted exposure to darkness.
This research has a number of exciting potential applications in pregnancy care especially when we consider that artificial lighting is so prevalent in birthing hospitals around the world, and could be inadvertently affecting labor progression.
These applications could include:
– using light exposure or melatonin antagonists to suppress melatonin in pre-term labour situations
– supporting melatonin levels via decreased light exposure to support the progression of natural labour
– potentially using light-suppression and/or melatonin agonists (exogenous melatonin) to induce labour
We are not at the point of being able to recommend potential melatonin dosing to promote initiation or progression of labour, but this study certainly lends credibility to the instinct many women have to turn the lights down low during labour!
I hope you have found this helpful, and do let me know if you have any questions!
If you are hungry for more evidence-based information in your pregnancy, sign up for my free webinar: 7 Pregnancy Myths Debunked – and get the information you need to have a healthy pregnancy and a thriving baby.
And if you are a care-provider looking for evidence-based resources for your pregnant patients, please get in touch with us at support@myhealthypregnancyplan.com.
In health,
Dr Jocelyn Land-Murphy, ND
Terra Life
Disclaimer: The information and content provided is for general educational and informational purposes only and is not professional medical advice, nor is it intended to be a substitute therefore. Please consult the Disclaimer and Terms of Use for full details.
References:
Rahman, S. et al. (2019).Relationship between endogenous melatonin concentrations and uterine contractions in late third trimester of human pregnancy. Journal of Pineal Research.