Baby obesity research: no need to panic

Behind the Headlines

Monday April 2 2012

Major research is looking at the risks of obesity in pregnancy

Babies are to be “treated in the womb for obesity”, according to the Daily Mail. The newspaper said that overweight mothers-to-be will be given a diabetes pill “to cut the risk of having a fat child”.

The news is based on an ongoing study to find out if giving the diabetes drug metformin to obese pregnant women can reduce the risk of their babies being born overweight. This is of interest as obese women tend to have poorer control of their blood sugar, a problem that metformin can help regulate in people with diabetes. If exposed to excess blood sugar in the womb, growing babies may be born with excess birth weight, which has been linked to difficulties during birth and illness in later life.

While the Mail’s front-page presentation of this research might make this research seem frightening or frivolous, it should be noted that metformin is already used to help some pregnant women control their blood sugar and prevent complications. The study has also gone through various safety checks to ensure it does not pose any significant risks to either mother or baby and that it could be of potential medical benefit.

This research is neither new nor finished yet, and it is unclear why the Daily Mail has chosen to cover it. This study began in 2010 and will run until 2014, when its results will be revealed. Only then will we be able to see if the research is truly newsworthy.

 

What is metformin?

Metformin is currently used by patients with type 2 diabetes to control their blood sugar levels. It is commonly the first choice of medication for the treatment of type 2 diabetes, particularly in overweight and obese patients. In type 2 diabetes, patients build up too much glucose (sugar) in their blood, which can make them very ill. This happens either because they do not make enough of the hormone insulin, which regulates glucose levels, or because the body does not make effective use of the insulin that is made (because the body’s cells are no longer “sensitive” to insulin).

Metformin works by reducing blood glucose levels. It does this in several ways: it lowers the amount of sugar created by the liver, helps the body’s cells to make use of the insulin that is produced by the pancreas, and reduces the amount of glucose absorbed by the intestines. In the treatment of diabetes, metformin may be used alone, or if blood sugars are still not controlled, in combination with other diabetic drugs that have slightly different mechanisms of action. Metformin only works if the body is still able to produce some of its own insulin and, therefore, is not used to treat people with insulin-dependent forms of the condition.

Another beneficial effect of metformin is that it doesn’t cause weight gain (as can happen with some other first-choice diabetes medications), and it may in fact cause weight loss.

 

What problems does obesity in pregnancy cause?

The researchers pointed out that obesity among pregnant women is rising rapidly, and the prevalence among pregnant women is now over 15% in many UK hospitals. Women who are obese during pregnancy have a higher risk of several pregnancy-related complications, including gestational diabetes, pre-eclampsia, premature birth, caesarean section and having a baby born larger than average (which can complicate the birth).

There is also an increased risk of the baby being stillborn or the mother dying, though it is important to note that today, these outcomes are rare in any pregnancy. The Daily Mail’s coverage placed too much emphasis on the risks of death in the baby and mother due to obesity, suggesting this is far more common than it is.

In addition to the immediate problems, there is reported to be evidence that the effects of maternal obesity persist into the baby’s adult life. A higher-than-average birth weight is associated with an increased risk of obesity as an adult, with all the attendant chronic health problems, such as risk of diabetes, cardiovascular disease and possibly premature death.

 

What is the purpose of the trial?

The purpose of the ongoing trial is to find out if giving metformin to obese pregnant mothers improves health outcomes for either the mother or child, and particularly whether it reduces the baby’s chance of being born with excess birth weight.

In the research, the birth weight of the baby is being used as a marker for future risk of obesity, since excess weight at birth has been associated with risk of obesity as an adult. The trial will also investigate whether metformin can reduce the risk of metabolic syndrome. Metabolic syndrome is the name for a group of risk factors that raise the risk of heart disease, diabetes and stroke. These risk factors include a large waistline, low levels of HDL (“good”) cholesterol, high blood pressure and high blood sugars.

Researchers believe metformin may help reduce the incidence of babies with high birth weight by improving the woman’s sensitivity to insulin and, therefore, lowering the amount of excess blood sugar available to her baby. Obese pregnant women are said to be more resistant to the actions of insulin than lean women, which means they need to produce higher amounts of the hormone to keep their blood glucose at the same level. This suggests a potential role for metformin in obese pregnant women.

Women with higher levels of blood glucose tend to have a higher risk of other pregnancy problems. Alongside their primary outcomes relating to baby weight, the researchers will also collect information to explore whether treating obese women with metformin also improves the risk of these other problems.

 

How will the trial work?

The trial, called EMPOWaR, is being run by researchers at the University of Edinburgh, from 2010 to 2014. It hopes to recruit 400 obese pregnant women from Edinburgh and centres in Liverpool, Coventry, Sheffield, Bradford and Nottingham. It is a randomised controlled trial in which one group of women will be given the drug from week 12 of pregnancy until the time of delivery, and a second group who will be given a placebo (dummy) pill. The women and their babies will be followed-up for one year after the start of treatment.

 

Is metformin safe for pregnant women?

Though metformin is not formally licensed for use during pregnancy, it appears to be safe in pregnancy and can be prescribed “off licence” when a doctor deems it necessary. It may be used either alone or in combination with insulin for the treatment of existing diabetes (present before pregnancy) or for gestational diabetes (which develops during pregnancy). In women with gestational diabetes, metformin will be stopped after the woman has given birth, when the condition tends to naturally pass.

 

Should I lose weight before I get pregnant?

If you are overweight or obese and plan to get pregnant, talk to your doctor or a dietitian for advice on a weight loss programme. This should include both a healthy diet and regular exercise. However, if you are already pregnant, you should not try to lose weight without medical supervision.

 

Should I 'eat for two' during pregnancy?

You will probably be more hungry than usual, but you don't need to “eat for two”, even if you are expecting twins or triplets. Have a healthy breakfast every day because this can help you avoid snacking on foods that are high in fat and sugar.

You don’t need to go on a special diet when you are pregnant, but it's important to eat a variety of different foods every day to get the right balance of nutrients that you and your baby need. Eating healthily often means just changing the amounts of different foods you eat so that your diet is varied, rather than cutting out all your favourites. There are, however, some foods that should be avoided during pregnancy. Read more information about healthy eating during pregnancy.

Around 2-5% of women who give birth in the UK will have some form of diabetes, although most of these will have gestational diabetes. Women with diabetes may be required to modify their diet in some way, although their midwife or doctor will be able to give them specific advice on any changes they need, as well as information on whether they need to monitor their blood pressure.

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The 2 comments posted are personal views. Any information they give has not been checked and may not be accurate.

Pika_Lou said on 30 June 2013

I was put on metformin as part of my infertility treatment.

I have a BMI of 30 and no symptoms of diabetes, so it was mostly a precautionary measure due to the difficulty of my situation.

I am on a high dosage and it does make you feel sick when you first go on it, it is a common symptom, but it soon subsides.

During my pregnancy I have had no sickness at all, which is linked to blood sugar, and my baby is growing perfectly.

I won't be on it for the duration, but it doesn't appear to have caused any harm taking a high dosage during the developmental stage of my pregnancy.

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DanniBird said on 03 April 2012

I am overweight and whilst pregnant with my daughter I was told I had gestational diabetes. I was told I was border line and had I have been in a different city the blood tests I had may have been classed as 'clear'.
I was told to take the Metformin on a low dosage and then asked to double it after a week despite my blood levels remaining normal throughout daily blood testing. As the Metformin had increased my sickness levels it was decided that I keep on the lower dosage. Throughout my pregnancy my blood was always on the lower side of ' normal'.
Towards the end I was admitted to hospital for high blood pressure and my baby was delivered 3 and a half weeks early and only weighed 4lb 6oz. I assumed that this was due to the pre-eclampsia but now i read this it makes me wonder if the Metformin also had something to do with my baby being too small at birth. Would she have been smaller if i had upped my dosage of Metformin as requested?
My daughter is now 2 and half and only weighs 26lb.
If I was to have another child in the future I would want to monitor my blood levels and work with the doctors before agreeing to take the Metformin as 'standard'. I do not feel it helped me during my pregnancy and now they say it can and will be used to control the babies weight I feel that it may have contributed towards the tiny birth weight of my daughter.

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Analysis by Bazian

Edited by NHS Choices