Birth workers often joke about all babies coming at night, but the truth of the matter is – they really do! True, every now and then, we are blessed with a babe who decides to make their entrance into the world in the light of day, but this is not the norm.
In a study published in 2018, researchers reviewed statistics of over five million births that occurred in the UK between 2005 and 2014, and found that 71.5 percent of spontaneous births occurred during the evening or early morning hours – the majority occurring between the hours of midnight and 6am.
This information feels super validating to this oft sleep-deprived midwife, but it does beg the question – why?
There could be an evolutionary component to why our babies are born at night. It might have been safer for our ancestors to birth at night, when their communities gathered together after being dispersed during the day, and could afford more protection and assistance. Nighttime could have been a safer time to birth without fear of being hunted by predators.
But, of course, hormones play a very large role in why labor happens at night. Melatonin, that blessed hormone that helps lull us into blissful sleep, also helps to start labor. Though it may seem hard to believe, given how difficult it can sometimes be to sleep when we are pregnant, melatonin levels rise towards the end of pregnancy. The uterus develops more melatonin receptors, making the uterine muscle more sensitive to that extra circulating melatonin.
But wait – doesn’t oxytocin make labor happen? Of course, oxytocin is what makes the uterus contract and brings the baby out, but melatonin seems to play a vital role in birth by increasing the effect of oxytocin on the uterus, and making contractions stronger.
It all makes sense – why we want to retreat to a dark cave in our birthing hours, why the bright lights of a hospital room can disrupt our labor patterns. Hormones, as we know, are sensitive to interference. It’s helpful to know that an action so simple as dimming the lights in the birth room can help labor to progress normally.
While all of this great info doesn’t quite take away the pain for birth workers of routinely losing sleep in the name of normal birth, it’s nice to know that there is a rhyme and reason to the way our amazing bodies work.