An emergency delivery during childbirth is much more likely if the mother is older, a new study has found.

Norwegian researchers set out to investigate the link between maternal age and emergency operative deliveries, including emergency caesarean sections and operative vaginal deliveries, i.e. the use of forceps or ventouse.

They looked at almost 170,000 first-time mothers who were all considered to be at low risk of experiencing complications.

They found that 22% of women over the age of 40 required an emergency caesarean section, compared to just 6% of women aged between 20 and 24 and 8% of women aged between 25 and 29.

Just over 23% of women over the age of 40 also required an operative vaginal delivery, compared to 13% of women aged 20-24 and 16% of women aged 25-29.

The main reasons for emergency deliveries were foetal distress and dystocia (abnormally slow or difficult labour).

The study also found that the use of epidurals was linked to emergency deliveries and again this risk was greatest in older mothers. In those aged 40 and older, the difference in rate of emergency caesareans between those who had an epidural and those who did not was almost 13%. However in women aged between 20 and 24, the difference was just under 6%.

Meanwhile the study also noted that being overdue by two weeks or more, a high birth weight and induction of labour were all linked to an increase in emergency deliveries - and all of these risks were even greater the older a woman was.

The researchers from Oslo University Hospital concluded that the absolute increase in risk of requiring an emergency delivery is greater among older mothers.

"Previous research around advanced maternal age has mainly focused on high-risk pregnancies. However, most women of advanced maternal age are healthy, of higher socioeconomic status and are low risk. Our results show that the proportion of operative deliveries increased substantially with maternal age in a low-risk, first time mother cohort.

"These findings are particularly helpful for both healthcare professionals and women of advanced maternal age in decisions regarding the optimal mode of delivery," they commented.

Details of these findings are published in BJOG: An International Journal of Obstetrics and Gynaecology.

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