Victorian hospitals are having to manage more cases of severely obese women during pregnancy as the rate of obesity in the community continues to rise.

Obstetricians say the risks it poses to women and babies during pregnancy and labour are not widely understood.

The care of obese women - and the issue of when they should be transferred to major city hospitals - has come under the spotlight following the death of baby Mabel Windmill shortly after she was born at Latrobe Valley Regional Hospital in 2012.

The Victorian Coroner's Court heard Mabel could have survived if born earlier but her obstetrician believed a vaginal delivery was safer for her mother, Kathryn, whose high body mass index put her at increased risk of complications.

The case both highlighted the risks faced by obese mothers and raised questions about whether Victorian hospitals, particularly in regional areas, are equipped to manage their care.

Monash Health director of obstetrics Euan Wallace said obesity in pregnancy had emerged as a major problem only over the past decade, and was becoming more extreme.

A healthy body mass index – or BMI, an estimate of fat based on a person's height and weight – is between 18.5 and 24.9 for an adult. An obese woman has a BMI of more than 30.

"Ten years ago we would not have seen anyone with a BMI of 50, but now we'll see one or two women a month," Professor Wallace said.

"I had never, until the last couple of years, seen a women with a BMI of 60, but we'll now see half a dozen a year," he said.

Some women seen by specialised clinics at major Melbourne hospitals weigh more than 150 kilograms.

Professor Wallace said the risks to mothers and babies increased with BMI. At the high end, probably above 40, women could not be safely cared for in small centres.

He said caesarean sections for such women were "incredibly complicated surgeries with extremely high rates of complications".

"When we have a woman with a BMI of 50 needing a caesarean section we would have several pairs of very senior hands on board, [including] specialist anaesthetists, obstetricians and paediatricians," he said.

Mercy Hospital for Women director of perinatal medicine Professor Sue Walker said as BMIs kept creeping up, there was a danger of "normalising" problems of excess weight, particularly at the lower end of the spectrum.

"In the community, we've got used to regarding relatively low increases in BMI as being normal. But it's important for us to take time to assess a woman's BMI and stratify the risks that we should be looking out for during pregnancy," she said.

"The scale of it means that we need to be thinking about this in every area of maternity care. It's not just an outlier anymore but part of the mainstream population."

Royal Australian and New Zealand College of Obstetricians and Gynaecologists president Professor Michael Permezel said smaller hospitals usually had "bariatric policies" for pregnant women giving an upper weight limit beyond which they would transfer care to a larger centre.

He said some hospitals were not clinically equipped to manage women with very high BMIs, and women needed to be cared for elsewhere "in the best interest of their own health and that of their baby".

Increased complications faced by obese women meant they required frequent prenatal checks for pre-eclampsia and gestational diabetes, and specialised care during labour.

Professor Wallace said he believed greater efforts were needed to develop a "seamless chain of service" where women could move up from a rural, regional to tertiary hospital as their risks increased.

"We've had referrals at the 11th hour. A referral with one week to go is a very unsafe referral - it's very little time to meet with the woman and talk with her and plan things that could've been planned months ahead," he said.

He said a regional structure would overcome such difficulties, and women should not always be transferred to city hospitals.

"I think a much more acceptable and less stigmatising solution is to ensure the capabilities of regional centres can meet the needs of these women, and I think in most cases they do," he said.

"In some cases they have been less proactive and they have been caught out so they've recognised all of a sudden, we've got women we can't look after safely, and that just needs a bit of planning and support."

Professor Wallace said public hospitals needed to respond to the needs of the population by caring for obese women in pregnancy, but also highlight what was a worrying trend.

"It's become much worse than smoking. Women with a BMI of over 50, the outcomes of those pregnancies are worse than for women who smoke," he said.

"We need to be feeding back and having this conversation. This is a huge health burden for our society, and we need to think about how to start reversing it."