A new study, conducted by the researchers at the University of Massachusetts Amherst, has found that higher-intensity exercise is associated with early pregnancy loss in women with a history of miscarriage.
However, in women with confirmed pregnancy, exercise, and miscarriage risk were not related.
Lead study author Lindsey Russo said, “Risk related to physical activity is different for pregnancy failure close to the time of implantation compared with that for later, clinical pregnancy loss.”
The study, published in the journal Fertility and Sterility, sheds new light on the question of physical activity and early pregnancy.
“The implantation period may represent a time of vulnerability, when high-strain activity could pose a risk for subclinical, or very early pregnancy loss,” Russo said, though experts say larger studies are required to further examine the issue.
“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,” she added.
Senior study author Brian Whitcomb said, “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,” he added, “Few studies are able to do this.”
Whitcomb explained, “Physical activity is a complicated measure. It represents a combination of being health-conscious, as well as the physiological effects of physical activity, which is generally good for physical health but can also be a stress.”
The researchers defined physical activity in terms of time spent and intensity levels to calculate an overall exercise score.
“We’re trying to provide good, evidence-based information for women who are pregnant and want to know what to do and also for clinicians who are giving guidance and advice to their patients,” Whitcomb said.
Russo noted that according to the American College of Obstetricians and Gynecologists’ recommendations, “women with uncomplicated pregnancies should be encouraged to engage in aerobic and strength-conditioning exercises before, during, and after pregnancy.”
The researchers said their findings suggest that women who have a history of miscarriage should avoid high-intensity exercises in the earliest stage of a subsequent pregnancy. Whitcomb explained, “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.”
