The American College of Sports Medicine (ACSM) has recently published an umbrella review that reviews all of the scientific studies ever conducted regarding exercise and pregnancy. This article reviews this paper and summaries the evidence and guidelines for exercise and pregnancy.
Gestational weight gain
Weight gain is a given in pregnancy, but how much should you gain? Luckily, there are official guidelines, fully detailed here. As a guide, a woman with a normal BMI (18.5-24.9) should expect normal gestational weight gain of 11.5-16kg. Anything more than that would be considered excessive, and anything under that would be considered less than desirable. There is very strong evidence suggesting that exercising during pregnancy reduces excess weight gain. The evidence shows that moderate intensity cardiovascular exercise (such as aerobics, walking and swimming) for 30-60 minutes at least three times a week significantly decreases the chances of excess weight gain during pregnancy.
Gestational diabetes is a condition in which a mother with no evidence of diabetes pre-pregnancy develops high blood sugar levels during pregnancy. Although many expectant mothers do not experience symptoms as a result, gestational diabetes increases the risk of pre-eclampsia, depression, and requiring a caesarean-section. There is very strong evidence that exercising during pregnancy decreases the risk of developing this condition by 27 percent on average. Even better, though, exercising before and during pregnancy further decreases the risk of developing the condition by 38 percent.
Pre-eclampsia and gestational hypertension
Pre-eclampsia is a condition in which an expectant mother experiences high blood pressure and high levels of protein in the urine, especially during the second half of pregnancy. The evidence surrounding exercise and these conditions suggests there is a dose-response relationship the risks of developing the condition lower as the amount of weekly exercise increases, until about five hours per week, where if the expectant mother did more exercise, the decrease in risks get smaller, with studies suggesting that five hours/week is the sweet spot.
Anxiety can affect expectant mothers both pre and post-partem and can have a large impact on the mental health of the mother. The evidence suggests that practising yoga during pregnancy can significantly reduce various forms of anxiety.
Depression is a major concern for mothers, and exercise has been shown to help both during and after pregnancy. Studies have shown that practising yoga during pregnancy can reduce symptoms of depression, plus moderate intensity aerobic exercise post-partem has been shown to reduce the incidence of post-partem depressive symptoms.
The bottom line
Almost all of the evidence suggests that exercising during pregnancy yields many benefits for both mother and baby. Aerobic based exercise 3-5 times per week potentially yields the most benefits, with the addition of yoga yielding extra mental health benefits too.
One of the key things for the expectant mother though is to listen to their body. If you don’t feel right exercising, stop straight away, and if you don’t feel like exercising one day (or one week, or even one month!), it’s okay. Just get back into it when you feel ready.
Mike Trott is a UK-based fitness professional who specializes in sports personality psychology and sports exercise physiology. He has conducted academic research into group exercise interventions and personality, exercise addiction, and foam rolling physiology, and is also a multi-award-winning Les Mills instructor, trainer and presenter.