After training for five years to become a nurse, Bernadette Hoban set off on a round-the-world trip before settling down in the West Midlands to get her career back on track. She was 30.

Hoban might have started thinking then of starting a family with her boyfriend Dominic Roche, but Maria, her sister, developed cancer and for five years Bernadette helped look after her three children. Like thousands of women in Britain, it was only when Bernadette turned 40 that she started thinking about having a family.

It was not straightforward. Although she had never anticipated having problems conceiving, Bernadette, who is now married to Dominic and known as Hoban-Roche, was unable to become pregnant naturally and turned to infertility treatment.

Only after five gruelling rounds of in vitro fertilisation (IVF) and more than one miscarriage did she finally give birth, at the age of 43, to a daughter, Hannah Emilia — now nine months.

“Like so many women I just did not consider it might be a problem having children a bit later,” said Bernadette last week. “But it just didn’t happen. And the IVF treatments at Midlands Fertility Services proved an emotional rollercoaster. In the end we were very fortunate.”

Her experience is not unique. The latest figures show 49% of births in 2003 were to mothers aged 30 plus. The average age for a married woman to give birth is 31 and almost 20,000 births are recorded each year to women over 40.

While commentators from right and left have dedicated countless speeches and column inches to older women and the family, few have stopped to question the trend towards late motherhood on medical grounds.

That changed dramatically last week when the British Medical Journal (BMJ) dropped an unexpected bombshell. In its editorial it warned there was a strong biological argument for halting the trend towards older motherhood.

BY missing the “biologically optimal” child-bearing window of 20 to 35, thousands of women each year in Britain were putting their wellbeing at risk, it said. The cost to the National Health Service was out of control and — worst of all, perhaps — children were facing a greater risk of being born with handicaps.

“It is ironic that as society becomes more risk averse and pregnant women more anxious than in the past, a big preventable cause of this ill health and unhappiness is unacknowledged,” said the BMJ. “Public health agencies target teenagers but ignore the epidemic of pregnancy in middle age.”

The report went on to suggest that the much talked about availability of infertility treatments was lulling women into a false sense of security, with many believing IVF was a reliable and easy option.

One of the authors, Dr Susan Bewley, consultant obstetrician at St Thomas’ hospital in London, said: “Women want to ‘have it all’, but biology is unchanged. Delaying defies nature and risks heartbreak.”

So is the medical profession, as represented by the BMJ, right? If so, what should the government be doing to encourage earlier births? Despite seemingly endless advances in medical science, there can be no doubt that older women still face greatly increased risks in pregnancy. According to the BMJ report, delaying childbirth beyond the age of 35 poses three big medical problems.

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