Birth looms large for a sizeable number of mothers

Looking after little Ellie was tiring enough; harder still when Claire realised that being a size 20 and weighing around 15 stones wasn't helping.

She'd piled on the pounds as a youngster, partly the result of an unhealthy diet and partly down to a medical condition that played havoc with her hormones.

Now she had a baby and the extra weight was even harder to bear.

Three years on, though, she is a mere fraction of the mum she was. A slim size ten, she's shed more than six stones to become the yummy mummy she always wanted to be.

"I didn't realise the impact my weight would have on me becoming a mum," admits Claire, 26, a post office worker from Fauldhouse.

"Things like constantly bending down to change nappies and running around, tidying up, were exhausting."

Of course, Claire's not alone in finding that juggling babies and battling the bulge are a challenging combination. Half the women in the UK of child-bearing age are overweight, or obese, and earlier this week the Royal College of Midwives and parents' website Netmums highlighted the pressures pregnant women and new mothers face.

Their research pinpointed the torment as mums struggle to match stick-thin celebrity mothers and the lack of advice available from hard-pushed midwives with neither the time nor the expertise to guide them through their changing body shape.

• A hefty problem for the NHS

Cathy Warwick, general secretary of the midwives association, says: "There is a real need to address the issue of obesity. The growing volume of evidence shows the health of an obese mother is further compromised by the pregnancy and also has an impact on the health of her unborn baby."

The survey warned many feel intense pressure to crash diet post-birth to match skinny celebrity mums and that few understand the pressures pregnancy places on their body and their child's health.

Those risks are being unravelled by a team at a unique clinic at Edinburgh's Western General hospital which aims to monitor the impact obesity in pregnancy has not only on mum but their babies and the health service.

Launched two years ago with funding from national baby charity Tommy's, the Edinburgh antenatal metabolic clinic has already monitored more than 200 heavily overweight women through their pregnancies.

As Scotland's obesity crisis grows, business at the clinic is thriving.

"There is an increasing obesity problem nationwide that includes women of reproductive age," says Dr Fiona Denison, consultant obstetrician at the unit."About 43 per cent of women in Lothian have a BMI (body mass index] greater than 25. That's quite substantial.

"The number of severely obese is less, but it still has big implications on the service we provide."

For, as Dr Denison explains, in heavily overweight mums-to-be the issues go much deeper than looks alone.

"Women who are overweight or obese in pregnancy can have an increased chance of miscarriage through to difficulty getting pregnant. There's also a higher chance of the baby being born with spina bifida or congenital problems.

"There's a higher chance of high blood pressure and diabetes for the woman and an increased chance of their baby dying during the pregnancy or being admitted to the special care baby unit afterwards."

Heavily overweight mums-to-be - the clinic deals with women with a BMI which is greater than 40 - usually require extra-large blood pressure equipment to fit larger arms to ensure a correct reading and there can be problems for midwives attempting to monitor the size of their growing baby.

There is also evidence to show the placenta does not work as effectively in women with a weight issue and questions over how stress hormones in pregnancy may be affected by weight, impacting on the health of the baby.

One key area of the team's research looks at the impact of the mother's weight on her unborn baby's own potential to be overweight as they grow up.

"If the woman is overweight during pregnancy and puts more weight on, there's a chance of her baby being born big," adds Dr Denison. "Babies are born with fat cells which are laid down in the womb. If they're laid down in the wrong places then it's harder for babies to remain at normal weight as they grow. There's an inherited chance of them being obese in early childhood."

There are risks during labour, too. "There is a higher chance of Caesarean section and the challenges of doing that in a very overweight woman means an increased chance of post-delivery problems.

"After the baby is born, there is a higher chance of clots so women often have to have a series of injections."

Pregnant women who attend the clinic as part of their antenatal care are not, however, encouraged to diet. "That would not be good for the baby. They are seen by a dietician who talks about their health and exercise and they are advised not to gain a huge amount of weight, but ideally they should keep their weight about the same."

While Claire, Scottish Slimmers' Slimmer of the Year 2009, didn't attend the clinic, she now realises the stress she put on her body during pregnancy.

"I'd always been big," she says."I don't think I really knew how my weight could affect my pregnancy.

"I know that I was exhausted but I thought that was just how you were supposed to feel."

Claire, who is 5ft tall, weighed around 15 stone when she fell pregnant, a combination of unhealthy eating habits and polycystic ovaries (PCOS), a complex hormonal condition that can affect fertility and make losing weight even harder.

Daughter Ellie, now four, was born without any complications, but it was a year before Claire accepted the toll her weight was placing on her efforts to be a good mum.

"It was things like getting up from the floor after playing with her or changing a nappy," she recalls.

"I realised I had to make a change. I joined Scottish Slimmers and it was the best thing I could have done."

According to Dr Denison, the extra monitoring mums receive at the Western's clinic often inspires them into losing weight after the birth. "A lot of women are uncomfortable talking about their weight. However, most who come to us stay when they realise the health implications," she says. "They become overwhelmingly positive and end up recommending the clinic to friends."

Find out more about the Edinburgh antenatal metabolic clinics at www.tommys.org or Scottish Slimmers at www.scottishslimmers.com.