World’s Largest Study of How Exercise and Healthy Diet Interventions in Pregnancy Improve Health of Mothers and Babies
Globally – half of all women of childbearing age are overweight or obese and women generally are gaining excess weight in pregnancy. This excess weight gain is putting women at greater risk of complications including having a preterm birth, caesarean section and gestational diabetes. These conditions not only put both mother at risk during pregnancy and impact the baby’s health, but also impact child health through into adulthood with an increased risk of chronic illness.
New data from the world’s largest study looking at the impact of lifestyle interventions in pregnancy has crushed the myth that eating for two is beneficial for pregnant mothers and that exercising is harmful to a baby. The landmark study, including Monash University’s Professor Helena Teede is published today in the British Medical Journal, and has found that maintaining a healthy diet and exercise through pregnancy has a significant impact on the health of the mother and baby – including reducing risk of caesarian section by 10% and gestational diabetes by 24%. Importantly these benefits occurred regardless of whether the mother was overweight or obese when becoming pregnant.
The study involved more than 50 researchers from 41 institutions in 16 countries and includes data from 12,526 women including thousands of women from Australia.
Previous studies have found that healthy diet and exercise during pregnancy can limit excess weight gain during pregnancy, but there is no consistent data on the protective health effects for mothers and babies.
Pooling and detailed analysis of information from 36 studies globally, the researchers compared the effects of healthy eating (including restriction of sugar sweetened beverages, promoting low-fat dairy products, increase in fruits and vegetables) and physical activity (moderate intensity including aerobic classes and stationary cycling, and resistance training for muscle groups) in pregnancy.
Healthy diet combined with physical activity significantly reduced the mother’s weight gain during pregnancy by an average of a 0.7 kg compared to the control group and lowered the odds of the mother having a caesarean section by about 10 per cent.
In addition, the data revealed that changes in lifestyle reduces the risk of gestational diabetes in pregnancy by 24 per cent.
According to Professor Helena Teede from the Monash Centre for Health Research and Implementation, Monash University and Monash Health the study is important because it dispels the myths that “eating for two” is beneficial for the baby and that exercising can in fact be harmful. “In this study we show that physical activity and a moderated healthy diet optimises mothers pregnancy weight gain and has direct health benefits,” she said.
The benefits include:
- a reduction in maternal gestational diabetes in pregnancy
- significantly less preterm births
- less Caesarean sections
According to Dr Cheryce Harrison, an exercise physiologist from the Monash University and co-author, the study emphasizes the importance of maintaining physical activity in pregnancy. “When pregnant the temptation is to rest and we have shown in Australian women activity levels fall dramatically in pregnancy. Yet here it is clearly important to maintain activity levels and meet standard recommendations for 150 minutes of dedicated activity per week throughout most of the pregnancy,” she said.
The authors called on immediate input from health policy makers in Australia and worldwide. “This is now clear evidence that pregnant women, around the world, should be supported, encouraged and monitored to optimise healthy diet and moderate exercise. Evidence shows healthy lifestyle advice is not enough, policy implementation to make healthy choices easier, as well as supportive pregnancy lifestyle interventions are needed,” Professor Teede said. “Action is vital not only because of the health of the mother and baby, but because of the enormous economic and health system impact that ignoring this issue is having.”
However many barriers remain to implement this research evidence into practice to keep Australian mother and babies healthy. Professor Teede noted that “Rather than just telling women to be healthier, and invoking guilt and sometimes despair, this research shows we need to directly support women with simple healthy lifestyle interventions as part of routine care, just as we do in smoking cessation, an area where Australia leads the world,” she said.
“We also need to train and support health professionals to deliver effective lifestyle interventions embedded into routine care and ensure that guidelines for pregnancy care are aligned and updated with this new evidence.”
Gestational diabetes normally affects over 1 in 7 Australian mothers in pregnancy, and increases costs of care and risks of complications in mother and baby.
Caesarean rates are high in Australia, partly driven by excess pregnancy weight gain, bring higher costs to the health system and can carry risks such as infections for the mother and breathing difficulties for the baby.
Currently in Australia few women are offered access to lifestyle programs on diet and physical activity to optimise healthy weight gain in pregnancy and improve outcomes for mother and baby.
This study found that healthy eating and physical activity has a beneficial effect across all groups, irrespective of a mothers starting weight, body mass index (BMI), age or ethnicity; confirming these lifestyle interventions benefit across the population.”
The study also found that there was no strong evidence that the interventions affected offspring outcomes such as stillbirth, underweight or overweight births, or admission to a neonatal intensive care unit. The lack of adverse effects should reassure mothers who have traditionally been advised not to undertake structured exercise or manage their diet in pregnancy.
The study was funded by The National Institute for Health Research (NIHR) Health Technology Assessment (HTA) programme in the UK.