In women with a history of miscarriage, higher levels of physical activity were associated with a greater risk of subclinical, or very early, pregnancy loss, according to new research at the University of Massachusetts Amherst. Among women with confirmed pregnancy, physical activity and miscarriage risk were unrelated.
“Risk related to physical activity is different for pregnancy failure close to the time of implantation compared with that for later, clinical pregnancy loss,” writes lead author Lindsey Russo, a Ph.D. student working with senior author Brian Whitcomb, associate professor of epidemiology in the School of Public Health and Health Sciences. Their study, which sheds new light on the question of physical activity and very early pregnancy, was recently published in the journal Fertility and Sterility.
There was roughly a two-fold higher risk of very early pregnancy loss for women who were highly active compared to those who were less active, the researchers said. Subclinical pregnancy loss can be difficult to detect because they may occur before a woman is even aware that she’s pregnant.
“We were able to address an interesting gap in the literature, where there has been conflicting evidence of whether physical activity can have a negative, beneficial or no effect on pregnancy. Determination of these very early pregnancy failures requires lab tests and daily specimen collection to identify pregnancies and losses. Few studies are able to do this” Whitcomb said.
The researchers say their study suggests that women who have lost a pregnancy may want to avoid high-strain activity in the earliest stage of a subsequent pregnancy, or around the time of trying to become pregnant.
“For women who are experiencing difficulty conceiving, our results are consistent with prior work that has also shown that high exercise strain during the implantation period may be related to increased risk of loss,” Whitcomb says.