Watch your weight for a healthy pregnancy

The majority of women of reproductive age in the Republic are either overwieght or obese, a new study has found

WITH SO MUCH being written and said about the health dangers of being obese, there is a growing risk of “health message fatigue” setting in. Especially as we live in a society populated by more overweight people, our internal sense of “normal” as far as body shape is concerned will change. Are we then even less likely to hear the advice about the risks of being obese?

Whatever about the general public there is a need for people with either a personal or a family history of cardiovascular disease to both listen and take action as measures such as their body mass index (BMI) climb above recommended limits. BMI is a reliable measure of our weight which evens out factors such as height and build. It is calculated as body weight in kilogrammes divided by your height in metres squared.

Now another group has come under the research spotlight – women of reproductive age. Researchers at the National University of Ireland Galway, led by professor of medicine Dr Fidelma Dunne, have been working on the wide-ranging Atlantic DIP study. As well as assessing the prevalence of diabetes among pregnant women in the Republic, it has found that the majority of women of reproductive age here are either overweight or obese.

Some 38 per cent of young women are overweight (with a BMI between 25 and 30), while a further 19 per cent are obese with a BMI greater than 30. In other words, just over four in 10 are a normal weight: for this group at least being overweight or obese is the new “norm”.

So? These are young and otherwise healthy women in the prime of their lives. Except that, in the words of Dr Conall Dennedy, specialist registrar and research fellow at NUIG and one of the Galway research team, “when we analysed the data collected we found that per unit increase in BMI, there was an increased risk of adverse pregnancy outcome for both mother and baby. And this risk was higher for women in their first or second pregnancy”.

Presented at the recent annual meeting of the American Diabetes Association, the findings confirm that obese women without diabetes have poorer pregnancy outcomes. As mothers’ BMI rises, so too do Caesarean section rates and the incidence of pregnancy-induced high blood pressure. There is also a direct link with increasing BMI and high birth weight; and babies born to obese mothers also have a greater risk of being born with a congenital malformation.

According to the Royal College of Obstetricians and Gynaecologists, pregnant women who are obese are at increased risk of miscarriage, deep vein thrombosis and wound infections compared with women who have a healthy pre-pregnancy weight. But rather than bombarding already obese women with a raft of negative statistics, is there a positive public health message that can be put out there?

Dennedy believes there is. “Given the new ‘norm’, women of reproductive age may not realise they are overweight or obese. But if we take our findings in context, a modest weight loss of 3kg to 4kg is likely to provide significant improvement in outcome for both mother and baby.

“There is good evidence to suggest that modest weight loss – 5 per cent of body weight, which approximates to 3kg-4kg – can reduce these risks by almost 60 per cent,” he says.

“This can be done by eating a healthy diet, which is low in fat (simply avoid desserts and fast food), and moderate exercise (four to five, 40-minute sessions per week, aiming to burn 400kcal-500kcal per session). Calorie counting also helps.”

He emphasises the best time to achieve weight loss is before or between pregnancies and it should be undertaken as a gradual project of slow lifestyle change. What about attempting weight loss during pregnancy? Dunne advises against this, but notes it may be appropriate for an obese woman not to add weight during pregnancy.

Recent guidelines from the National Institute of Clinical Excellence (Nice) in the UK contain practical advice for women with a BMI of 30 or more who are contemplating pregnancy.

It says that losing 5 to 10 per cent of their weight is a realistic target with the help of GPs and dieticians, and may even improve their chances of becoming pregnant. It also has useful advice for women wishing to lose weight between pregnancies (Nice Public Health Guidance no 27, nice.org.uk).

The key appears to be a gentle introduction of lifestyle change rather than sudden drastic steps such as crash dieting. “It is clear that the time for optimising weight is when pregnancy is being planned, ie before pregnancy or between pregnancies.

“This can be undertaken with relatively simple, small, lifestyle changes in which dietary improvements and exercise are introduced tolerably into the daily routine,” Dennedy says.

ATLANTIC DIP SURVEY: WOMEN TESTED FOR DIABETES

The Health Research Board funded diabetes in pregnancy study (Atlantic DIP) examined 13,257 deliveries at five hospitals along the Atlantic seaboard between February 2007 and September 2008.

Women who took part in the NUIG study were tested for diabetes between the 24th and 28th week of pregnancy. A positive test means the woman has gestational diabetes mellitus (GDM) which may have short- and long-term health consequences for both the mother and her baby. GDM disappears in most women after they give birth.

Babies born to mothers with GDM tend to be much heavier and have an increased risk of death in the womb. Mothers are more likely to need a Caesarean section and to suffer pregnancy-related high blood pressure.

Later in life, infants born to mothers with GDM are themselves more likely to have diabetes and to be obese.

The Atlantic DIP study found a doubling of pregnancy-induced hypertension in the women with GDM compared with those with a normal tolerance for glucose. It also found that Irish women with pre-existing diabetes were poorly prepared for pregnancy and their babies were more likely to die than those born to women without the disease.

Good news to emerge from the research was that the early identification and treatment of women with gestational diabetes led to their babies having normal birth weights.

Some 60 per cent of women responded to diet and exercise, while others required insulin treatment as well.