Why do more women give birth at night? Experts explain our 'evolutionary heritage'

Forget the dramatic scene of waters breaking in the middle of the supermarket aisle in broad daylight that you've seen in the movies: a woman going into spontaneous labour can actually be a very calm event, and without medical intervention, it is far more common at night.

A study done in London, published in 2018, took into account more than five million births within a 10-year period in England. The researchers – who hailed from both University College London and City, University of London as well as the National Childbirth Trust – found the majority happened after dusk.

While just more than a quarter of births in the study occurred between 9am and 4.59pm on weekdays, a whopping 71.5 per cent took place outside these hours.

A little more than half of the women, following the spontaneous onset of labour, gave birth between 1am and 8am, with the peak hour being around 4am.

But why? What is it about the cover of darkness that might cause a woman to start experiencing contractions?

The National asked a few maternity experts in the UAE to find out.

'Part of our evolutionary heritage'

“There seems to be an association with our biological history as to why the majority of babies are born at nighttime,” says Dru Campbell, head midwife and lactation consultant at Dubai’s HealthBay Polyclinic. She cites Dr Peter Martin from UCL’s Institute of Epidemiology and Health, who was the lead author on the aforementioned study.

Martin concluded: “Long-term experience and research from other areas has shown that human births without obstetric intervention are most likely to occur at night or in the early hours of the morning. This may be part of our evolutionary heritage. Our ancestors lived in groups that were active and dispersed during the day and came together to rest at night. So a nighttime labour and birth probably afforded the mother and newborn baby some protection.”

Doula and hypnobirthing instructor Lala Langtry-White, who is also based in Dubai, agrees with this conclusion. “Physiologically, the hormones involved in birth are released from the deepest and most primal parts of our brain. So, in the same way that any cat or dog owner will have noticed that they tend to hide under a bed or in a cupboard to give birth privately and protected, humans are not so different.”

It might also have something to do with the hormone oxytocin, Campbell adds.  “This is responsible for uterine contractions. Oxytocin is optimally released when a woman is relaxed and feels safe. Nighttime, when it is dark, may facilitate a calmer environment, especially if the lights are dimmed.”

Langtry-White adds that oxytocin is enhanced by melatonin, a hormone that regulates the sleep-wake cycle and is produced at night. “Hence overnight is when our contractions tend to be most productive.

“It is also why we teach couples to utilise this hormonal relationship by keeping the labour environment dark or softly lit. This enhances your feeling of privacy at what is such an intimate moment in your life,” she says.

Any perceived threat to our safety might actually slow labour down, she adds. “During early and active labour, adrenaline and catecholamines, our fight or flight hormones, can cause labour to slow down or stall, which would have been necessary if there was a real danger or threat to ours or our baby’s safety.

"It’s something we can see happening sometimes when parents transition into hospital, to unfamiliar and clinical surroundings. Though their safety may not be in any real danger, their body can react to the subconscious, perceived threat or lack of security felt in the unfamiliar environment.”

This is one of the reasons why hospitals often ask their patients to labour at home for as long as possible – at least until contractions are five minutes apart.

Why births in the middle of the day are now on the rise

Yet none of this accounts for planned caesarean sections or induced labours. In these cases, labour and delivery will more often happen during the day.

For example, the London study found that elective or pre-planned C-sections occurred mostly on weekdays between 9am and 11.59am. Very few took place after 5pm during the week, on weekends or public holidays. “This may be a reflection of staff working patterns and operating theatre schedules,” Campbell explains. These statistics would be very similar in the UAE, she adds.

“Emergency caesarean-section births can occur at any time of the day or night.”

As for induction, it all depends on when the process began. If, for example, a woman is induced in the morning, then it might result in her giving birth at night. “In the UAE, many obstetricians will commence inductions in the evening,” Campbell says. “This is to allow a woman to rest while the hormonal induction medication is working and then birth may occur during daytime hours.

“However, sometimes, spontaneous birth may occur quicker than expected and result in a woman giving birth during the evening or early hours of the morning. The exact timing of an induction of labour cannot be predicted as every woman is individual in how her body reacts to the medication or intervention.”

We asked the team at Dubai’s Medcare Women and Children Hospital what their statistics looked like and were told more women deliver during midday. “With rate of induction of labour rising globally, more births are happening in the midday, as mostly inductions of labour usually start at night,” says Dr Shiva Harikrishnan, a consultant obstetrician and gynecologist at the hospital.

“Elective and scheduled caesarean births occur in the morning hours rather than night.”

Remember, we are mammals

For the mums-to-be who end up being able to stick to a more natural path, their chances of delivering at night remain high.

“[This has] nothing to do with medicine, but is all to do with hormone production relating to the mammalian self-preservation and nature,” says Langtry-White. “Often in direct contrast to the medical standpoint of ‘convenient’ birth.”

She says the crucial role our hormones play in all this, and how they can be impacted and enhanced, are not yet fully understood and aren’t always given the respect they deserve.

“The famous obstetrician Michel Odent said: ‘If we can be more respectful of our mammalian roots, and the hormones that we share, we have more chance of a straightforward birth ourselves.’”

Langtry-White, who is also a mother-of-four and been present at more than 70 deliveries, has certainly seen her fair share of nighttime births. “There is nothing quite like watching the sun rise just as the birth of a baby signals the dawn of a new family and getting to bear witness to that is such a privilege.”