In fact, seven out of 10 births take place outside normal working hours.
An analysis of more than five million births in England found that overall 71.5% of births take place outside the hours of 9am and 4.59pm on a weekday.
The study, led by City, University of London, and published in the journal PLOS One, found the time and day that women give birth can vary depending on how labour starts and the method of giving birth.
Just over half of mothers give birth after labours which begin spontaneously, with researchers finding these were most likely to happen between 1am and 6.59am, peaking at 4am with a trough in the afternoon.
They were also slightly more likely to happen on weekdays than other days.
The researchers found just over a quarter (28.5%) of births occurred between 9am and 4.59pm on weekdays, while almost three quarters (71.5%) took place outside these hours at weekends, on public holidays or between 5pm and 8.59am on non-holiday weekdays.
Elective or pre-planned caesarean births accounted for 9.2% of births and were found occur mostly on weekdays between 9am and 11.59am, and peaking between 9am and 10.59am.
Very few occurred between 5pm and 6.59am on weekday evenings and nights, and even fewer at any time at weekends and on holidays, reflecting staff working patterns.
Differences between days were most pronounced among pre-planned caesarean births, which rarely occur at weekends or on public holidays, with the highest numbers recorded on Mondays and on weekdays after a holiday period, followed by Thursdays and weekdays before a holiday, which likely also reflects staff rotas.
Researchers said it was the first national analysis to look at all aspects of time of birth in England, carried out in collaboration with University College London (UCL) and the National Childbirth Trust (NCT).
The team linked data from birth registration, birth notification, and Maternity Hospital Episode Statistics and analysed 5,093,615 singleton births in NHS maternity units in England over a 10-year period from 2005 to 2014.
Though patterns of spontaneous birth have remained relatively unchanged in England since the 1950s, the researchers found that overall patterns of birth have changed following the rise in rates of obstetric intervention from the latter half of the 20th century onwards.
Authors said that the birth patterns could have implications for midwifery and medical staffing.
Lead author Dr Peter Martin, of UCL, who conducted the research while at City, University of London, said: “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.
He suggested the reason babies are more likely to be born at night could be attributed to evolution.
“Our ancestors lived in groups that were active and dispersed during the day and came together to rest at night,” he explained. “So a night-time labour and birth probably afforded the mother and newborn baby some protection.”
Claire Lyon, Midwife at Private Midwives, has some other theories about the study results.
“The findings of this research, which highlight that the majority of babies are born at night, won’t come as a surprise to midwives. Especially those who regularly work on labour wards, birth centres or attend home births,” she says.
“Labour and contractions are under the influence of two hormones. Firstly, Melatonin, which encourages sleep and oxytocin also called the love hormone. Melatonin surges at night because of its role in encouraging sleep whilst oxytocin is responsible for signalling contractions of the womb and progressing labour, which is also present in higher levels at night, when it’s typically dark and women are in a more relaxed state (& adrenaline which is an antagonist is lower).
“These two hormones are responsible for the orchestration and successful progress of labour, therefore, making giving birth at night quite a common thing.
However, birth is a complex process, affected by many factors including the woman’s body and baby’s position, which means it can be difficult to predict the exact time when a baby will be born.”
“This being said, as long as the baby is born safely and healthy that is the most important thing.”
And if that happens to be at 4am or at any other ungodly hour, then so be it.
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