As if having a baby isn't hard enough, new research suggests that labour is taking longer.

A study of almost 150,000 women found the average labour can last more than two-and-a-half hours longer today than 50 years ago.

This increase has been blamed on many 21st century mothers being older and heavier than their 1960s counterparts and changes in the way babies are delivered. For instance, the increased use of powerful epidural painkilling injections may be partly responsible.

US researchers compared data on almost 40,000 births between 1959 and 1966 with almost 100,000 deliveries between 2002 and 2008.


It revealed the first stage of labour - in which contractions have started but pushing has not - has got longer by an average of two hours 36 minutes in first-time mothers.
It increased by an average of two hours for those who already had at least one child.

Researcher Dr Katherine Laughon put the increase down partly to the differences in the women. The modern-day mothers weighed more before and during pregnancy and were, on average, around four years older than those in the 1960s group.

And more than half of the contemporary women had epidurals - which can prolong labour by between 40 and 90 minutes - compared with four per cent of 1960s deliveries.

In addition, women were usually confined to bed after an epidural, which may also slow down labour.

But Dr Laughon, writing in the American Journal of Obstetrics and Gynecology, said she could not fully explain the difference in labour times.

For example, changes in medical practice over the past 50 years - such as using the drug oxytocin to speed up labour - should lead to shorter delivery times. Dr Laughon said the lengthening of labour means doctors may be able to wait longer before intervening with oxytocin or delivering the baby by caesarean section.