By: 18 April 2018
Largest ever study of running habits of pregnant women shows that running in pregnancy is safe

Nearly 1,300 women were recruited from parkrun, which organises weekly five kilometre runs across the world. Women were categorised according to whether they continued to run during pregnancy or not. Information was collected on how many weeks into her pregnancy a woman ran, and how many kilometres she ran each week.

A poll of 1116 women on the Tommy’s pregnancy website, showed that more than a third were unsure if it was safe for regular runners to continue to run while pregnant, so the study is good news for runners.

Women from around the world responded to parkrun’s newsletter, making the study truly global. Details of previous pregnancies were collated, including gestation of delivery, birthweight and pregnancy complications. These were related to expected baby size by taking into account the mothers’ ethnicity, height, weight, and her baby’s gender, allowing an accurate assessment of running impact on pregnancy.

The results found that there were no ill effects related to the intensity or frequency of running during pregnancy and that continuing to run into the third trimester was safe. One woman ran a marathon the day before she delivered at term, while others ran regular half marathons throughout pregnancy. Even women pregnant with triplets enjoyed parkrun regularly.

Women are advised to exercise during pregnancy as it can lead to many health benefits and help women prepare for labour

“There are over 2.8 million park runners across the globe, many of whom are of reproductive age, running every Saturday morning. With parkrun’s assistance, in the biggest ever study of its kind, we have determined that running in pregnancy is safe. Women can continue accustomed exercise during pregnancy and we would encourage this to ensure a healthy outcome for both her and her baby” says Professor Andrew Shennan, lead author of the study and Professor of Obstetrics and Tommy’s Clinical Director at Guy’s and St Thomas’ Hospital.

Katy Kuhrt, study co-author and Research Fellow, Women’s Health Academic Group, Guy’s and St Thomas’ Hospital, comments, “The beneficial effects of running, including cardiovascular conditioning, reduced heart rate and blood pressure at rest, improved lung function, and a reduction in fat levels, have long been recognised. But the effect of regular, strenuous running on pregnancy health has been debated, and there is theoretical concern about adverse effects on pregnancy outcomes. We investigated whether the duration and intensity of running in pregnancy affects the number of weeks at which a baby is born and/or the birthweight of the baby.”

Professor Janice Rymer, Vice President for Education at the Royal College of Obstetricians and Gynaecologists (RCOG) says, “We recommend that all women take part in regular exercise during pregnancy as it can help to reduce fatigue, lower back pain, varicose veins, swelling of the ankles, and feelings of stress, anxiety and depression. This new study shows that, in the majority of cases, it is safe for both the mother and the baby if a woman who runs regularly continues to do so during her pregnancy.”

Abi Gooch is a 40-year-old police firearms officer from Milton Keynes. She’s been running for over 20 years, regularly takes part in triathlons and marathons, and needs to pass an annual fitness test for her job.

“I ran through both of my pregnancies and was fit and healthy throughout. I did a marathon when my first daughter was 7 months old and got a PB. With my second daughter I did parkrun on Saturday, a spin class on the Monday and gave birth to my daughter with a 4-hour labour on the Wednesday. Two weeks later I took part in a local 1-mile relay race.

“It doesn’t surprise me that running has been deemed safe during pregnancy. If you’re used to doing it and you still feel comfortable then why stop. It’s great for mental health, keeping the body strong for labour and I also found I got back to fitness quickly afterwards. I also found it helped me keep my identity and not just ‘a pregnant lady’ or ‘Mum’, I was still ‘me’. I have since completed over 50 marathons including some Ultra marathons and the Marathon Des Sables.”

Sophie King, a Tommy’s midwife, comments, “If you ran or jogged regularly before your pregnancy, you can carry on for as long as you feel comfortable. It’s a great aerobic exercise and can help women have a healthy pregnancy.”

Tips for pregnant runners include:

– wearing supportive running shoes and a proper bra that has been designed for runners
– focus on good technique rather than a fast pace
– look where you’re going so you avoid falling or colliding with anything
– don’t run yourself to exhaustion
– if you experience any unusual symptoms, stop exercising and contact your doctor or midwife

Picture caption: Natasha Hezelgrave, one of the research team, out running at full term. She delivered a healthy baby boy two weeks later.

Source: Tommy’s