Big mums risk babies' health

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Pregnant women are packing on too many kilograms, risking their health and that of their babies - and costing the health system a fortune.

A staggering 41.5 per cent of the 7735 women who gave birth at Auckland's National Women's Hospital in 2009 were classed as overweight or obese.

Those with a body mass index (BMI) of more than 25 were considered overweight, while those who exceeded 30 were said to be obese.

Previous data on pregnant weights at National Women's are incomplete and there are no national statistics on the size of expectant mums. But national and international research showed it was a growing problem, said Professor Lesley McCowan, of the University of Auckland department of obstetrics and gynaecology, who lectured on the issue to gynaecologists and obstetricians in Dunedin recently.

"It's a massive problem," she said. "It costs the health system millions and millions."

She said Kiwi midwives and obstetricians recorded weights and heights so they could advise patients of ideal weight gains.

Big mums, McCowan said, were at increased risk of:

* Developing diabetes and other serious pregnancy complications such as pre-eclampsia.

* Having a stillbirth. There is a two-fold increase for obese mothers.

* Needing a caesarean section.

* Breast-feeding problems.

* Having a big baby, which in turn is at risk of becoming an obese child.

She said the issue affected mothers of all ethnicities.

Big mums put a heavy strain on the health system, McCowan said, because they required more nursing and midwifery assistance. Many hospitals now have expensive super-sized beds and wheelchairs.

Auckland obstetrician Dr Martin Sowter said it was "worrying we're seeing about 100 women a year with a BMI over 45 (typically a weight of more than 130kg)". Another concern was a trend in pregnant women, aged under 25, being obese. Sowter said United Kingdom figures showed obese pregnant women were over-represented in death statistics and the issue was often linked with poverty.

He said the issue was changing the face of maternity care in New Zealand. "It's starting to impact on the way we deliver pregnancy care - more inductions, C-sections, bleeding and the babies are twice as likely to be admitted to the special care baby unit."

He said obese mums also had a higher chance of having a baby with an abnormality.

Dr Alec Ekeroma, of Middlemore Hospital in South Auckland, said their rates of overweight and obese mums were higher because many patients were Maori or Pacific Islanders.

According to the Counties Manukau District Health Board's annual report for 2009 births with recorded BMI data, about 59 per cent of expectant mums were above healthy weight.

Auckland's Dr Claire McLintock said about one in 500 pregnant Kiwis were morbidly obese (BMI over 50), compared with one in 1000 in the UK.

OBESITY FACTS

* The Ministry of Health says NZ is the third-fattest nation in the world, behind Mexico and the United States, according to a 2010 OECD report.

* Our males rank second worst alongside Australia, while Kiwi women are fourth worst.

* Things that contribute to weight gain include: reduced physical activity, increased consumption of processed foods, pregnancy at older age in overweight women and chronic stress.