A new study has found that the average time to childbirth varies from 1.5 to 3.5 weeks depending on the circumstances.
Researchers from the University of Bristol found that for babies born in the United Kingdom, the average gestation time is 5.7 weeks.
The study, published in the British Medical Journal, analysed data from the National Birth Defects Reporting System and other birth data sources.
“The average length of gestation is 5-6 weeks, and it is common for babies to have a cesarean section or vaginal birth in a single delivery,” Dr Jorgen Eriksen from the Department of Epidemiology and Population Health at the University said in a statement.
“We found that this was also true for babies of the same age and gestational age.”
The study, which was funded by the Department for International Development, compared the average length to the average pregnancy duration in different countries, with an average gestation of about 5.6 weeks.
In comparison, the UK average gestation is 6.1 weeks, the US is 6, and Canada is 7.
Dr Erikse added that the researchers found a correlation between the average gestational length and the age of the mother, which could lead to differences in outcomes.
“When the mother is younger, her pregnancy lasts longer,” he said.
“For a mother to be pregnant in her 30s and 40s, the pregnancy duration and gestation will vary from birth to birth.”
Dr Ersen said that there is no single factor to consider when it comes to the duration of labour, including how much time the mother spends in labour.
“Some of the factors that may have an effect are maternal age, maternal BMI, and fetal alcohol syndrome,” he explained.
“If we were to take a look at the effect of these things on the length of labour we would see an effect of about 1-2 weeks.”
Dr Ola Johansson from the Institute of Reproductive Medicine at Lund University said that the study is interesting and validating, but it doesn’t tell the whole story.
“I don’t think it gives us a good picture of the effect the length or duration of the labour has on the baby,” she said.
“What we do know is that women who experience a vaginal delivery experience a shorter pregnancy, so we know the longer a vaginal birth lasts, the shorter a pregnancy.”
This is not a completely conclusive result, but we do have some evidence that this length of delivery, the longer it is, the higher the risk of developing fetal alcohol spectrum disorder, so this is a good indication of what happens during labour.
“Dr Johansson said that this study does not provide any evidence that a vaginal or cesarian delivery causes a shorter birth.