Dr. Dimitrios Mastrogiannis, director of the division of maternal-fetal medicine and an associate professor of obstetrics, gynecology and reproductive sciences at Temple University School of Medicine in Philadelphia, said, "Obesity is a different ballgame. Different hormones are playing around in obesity -- fatty tissue produces more female hormones, more estrogens. Other hormones are transformed into female hormones in the adipose tissue."
The research does not suggest packing on pounds to get pregnant, or backing off physical activity completely, he said.
"Exercise is a good thing. It's linked to less cardiovascular disease, less cancers, less diabetes," said Mastrogiannis, noting that physical activity is also linked to better pregnancies, easier labors, less pain and fewer induced births.
The bottom line of the study is that normal, non-obese women who want to become pregnant should stick to moderate aerobic exercise, Mastrogiannis said.
"We recommend our patients get moderate aerobic exercise, akin to 30 minutes a day is usually what we say. Walking is very important," he said.
"If they engage in very vigorous exercise -- running, fast cycling, gymnastics or swimming -- more than five hours a week, it makes them less fertile," Mastrogiannis said.
For more on pre-conception health, visit the American Pregnancy Association.
SOURCES: Lauren Wise, Sc.D., associate professor, epidemiology, Slone Epidemiology Center, Boston University School of Public Health; Dimitrios Mastrogiannis, M.D., Ph.D., director, division of maternal-fetal medicine, and associate professor, obstetrics, gynecology and reproductive sciences, Temple University School of Medicine, Philadelphia; March 15, 2012, '/>"/>
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