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.”