The number of births to women in that age group increased steadily from 3989 in 1976 to 11,756 last year, when there were more births to women aged 35 or over than to those between the ages of 20 and 24.

The most common age group for births in Scotland is now 30-34 as women delay starting a family. But experts have warned that many could find it difficult to have children as their fertility begins to fall in their late-20s.

Dr Maureen Porter, research fellow with Aberdeen University’s obstetrics and gynaecology group, said: “A lot of women do want to have children earlier than they do but their circumstances prevent them. The main thing is not having a stable partner. Another thing is not feeling secure in their home or the financial implications that go with having a child.

“The alarming thing is we have patients who don’t have a realistic view of IVF. It is stressful. It is also costly. They don’t understand the psychological difficulty or they overestimate the chances of success.”

She added that many older mothers end up having only one child, saying: “In my opinion that is not a good thing. I have interviewed people with one child who have expressed regret about that.

“Also, if you talk to an only child, often one of the things they are concerned about is their parents becoming older and them not having anyone to share that burden.”

The number of births in Scotland increased to 56,821 for the year ending March 2008 and women between the ages of 30 and 34 account for 27% of all maternities, compared with 13% in 1976.

The figures, published by ISD Scotland, show a stark difference depending on the socio-economic status of women. While 19 was the most common age for women living in areas of high deprivation to give birth, it was 32 for women in wealthier areas.

The statistics also showed the proportion of births that were by Caesarean section has trebled in the past 30 years, from 8.6% of all births in 1976 to 24.7% in 2008.

The rate of both emergency and elective Caesareans had increased and 10% of births in 2008 were by a planned section, either because of medical reasons or because the woman chose the procedure. Some 9.4% of births were with forceps. The Scottish Government’s Keeping Childbirth Natural and Dynamic programme aims to reduce the number of Caesarean sections through a range of measures, including having consultant midwives in health boards.

Jackie Mitchell, National Officer with the Royal College of Midwives Scotland, said: “A Caesarean section is major abdominal surgery. It can have implications for future pregnancies. If you have had one it increases the risk of having to have one in future pregnancies.

“Consultant midwives have particular focus, even for women with risk factors, to try and keep their labour as natural as possible. The hope is that that will help to reduce caesarean section rates.”

Mary Newburn, head of research and information at the National Childbirth Trust, said: “The figures indicate that maternity services are still failing to give a high number of women in Scotland the type of birth they want.

“Higher levels of medical intervention can take control away from women, and result in greater pain and a longer period of recovery.

“We need to see greater investment in maternity services and we hope the Keeping Childbirth Natural and Dynamic initiative in Scotland should help focus attention on strategies to actively support more women throughout labour and reduce interventions, giving them every possible chance to have a straightforward, normal birth.”

‘The change in your life is so drastic’

Case Study: Alison Friel is Mrs Average, according to a new study which reveals that new mothers are getting older. Like many of today’s new mothers, she waited until she was in her 30s to have her first baby.

Alison, a PR consultant in Glasgow, who lives with her husband, James, 34, in Falkirk, is 32 and her baby son, Leo, is just more than six weeks old.

“I always thought I would become a mum at some time, but you see your life in terms of school, university, job ... and then motherhood,” she said. “But you always wonder about your ticking clock as you get older. You don’t know if you’re going to be able to have a baby or not.

“James and I had lived together for four years and once we got married 18 months ago, we thought it would be a good time to start trying.” The assumption, she says, was that it would take a year to get pregnant. “But it was really quick once we decided. A lot of my friends haven’t been so fortunate.”

Alison is only six weeks into her demanding new role, a shock to the system at any age, but she says it’s the lack of sleep and the constant tiredness that’s the killer.

“I am knackered,” she admitted wearily. “You get peed on, pooed on and vomited on at 3am but you have to keep your sense of humour.

“Everything revolves round him. I love him to bits, but the change in your life is so drastic. Before, everything was done to your own schedule. He’s a very good baby but I would probably have coped better in my 20s. People of our age are quite set in our ways so it is a bigger adjustment when you are older. Suddenly, this little person comes into your life and he is in control of everything ...”

But the other side of being an older mum, she says, is that you’re more ready to settle down: “I’ve lived my life a bit more. We’ve travelled and worked abroad, found jobs we both like and have friends and family.

“You also start to really appreciate your parents and what they did for you. I would be totally lost without them. I don’t think people realise how hard a learning curve it is. It can put a test on the relationship, but it has cemented ours. I take my hat off to single parents.”