In vitro fertilization, or IVF, is an increasingly common assisted reproductive technology for infertile couples. In a study published in Reproductive Biology and Endocrinology, researchers in China review how exercise can affect IVF success rates.
IVF, or in vitro fertilization, is an assisted reproductive technology in which a woman’s egg is fertilized and cultured in a laboratory and then transferred to her uterus after several days. The success of IVF can depend on the health and age of the mother, with younger mothers having a success rate between 40% and 50%. Most women have successful live births by the fifth or sixth IVF cycle. However, IVF can be expensive and difficult, and doctors and patients would benefit substantially from improving IVF success rates.
Moderate exercise is typically associated with increased health and fertility, as well as better outcomes during pregnancy. However, preliminary research on the links between physical activity and IVF success rates have shown mixed results. In a recent study published in Reproductive Biology and Endocrinology, Chinese researchers Rao and colleagues investigated the effects of exercise on the success rate of IVF using published data from eight separate studies that included 3,683 couples.
In the studies reviewed by Rao and colleagues, there was a small but non-significant trend towards higher rates of implantation success associated with physical activity before IVF cycles. There was also a strong, positive link between regular physical activity and pregnancy, and women who exercised at least two and a half hours per week were between 1.5-2 times as likely to get pregnant via IVF as those who did not. There was no significant link between physical activity and miscarriage rates, and women who exercised regularly for at least two and a half hours per week were twice as likely to have a live birth as those who did not.
Moderate exercise has clear benefits not only for the mother’s health but for the prospects of conceiving via IVF and carrying a pregnancy to term. The physiological mechanisms by which this happens are not yet known but are likely tied to improving energy balance, insulin sensitivity, and sensitivity to some of the hormones used to induce ovulation during IVF. Age and body mass index (BMI) are other factors that influence the success of IVF procedures, and may also be linked to the benefits of exercise. Future work should focus on standardizing available data about exercise and IVF outcomes and establishing the physiological mechanisms by which exercise can benefit infertile women.
Written by C.I. Villamil
Reference: Rao M, Zhengyan Z, Tan L. Maternal physical activity before IVF/ICSI cycles improves clinical pregnancy rate and live birth rate: a systematic review and meta-analysis. Reproductive Biology and Endocrinology. 2018.