Navigation Links
Too Much Exercise Delays Pregnancy in Normal-Weight Women: Study

By Mary Brophy Marcus
HealthDay Reporter

THURSDAY, March 15 (HealthDay News) -- Exercise is a plus for women trying to become pregnant, but overdoing workouts might make it harder to conceive -- unless you're overweight, researchers report.

Usually a risk factor for most health problems, being overweight or obese didn't hinder fertility in heavy women who logged vigorous workouts -- running, fast cycling and aerobics. However, healthy-weight women who performed more intense workouts were more likely to experience delays becoming pregnant.

The study was led by U.S. and Danish researchers who tracked physical activity and fertility in thousands of Danish women.

While moderate physical activity was associated with a small increase in fertility rates among all women, study author Lauren Wise, an associate professor of epidemiology at the Boston University School of Public Health, said, "Our study found that higher levels of vigorous exercise were associated with lower fertility rates in normal-weight women, but not overweight and obese women."

Wise said the findings indicate that physical activity of any type might improve fertility among heavier women, but their normal-weight counterparts who want to improve their pregnancy odds should sub in low-key workouts such as brisk walking and gardening. In other words, marathon runners who want to conceive might want to scale back on those pavement-pounding workouts, she said.

Other studies of competitive female athletes suggest that intense workouts disturb women's monthly menstrual cycles and lead to a lack of ovulation and even the absence of menstrual periods, among other problems, Wise said. But, she added, high-intensity exercise might also impair implantation when a fertilized egg attaches to the wall of the uterus.

The researchers of the observational study recruited and administered questionnaires over the Internet to 3,628 women who ranged in age from 18 to 40. They had to be in stable relationships with male partners and planning to become pregnant, but not involved in any fertility treatments.

The researchers collected information on height, weight, reproductive and medical history, plus lifestyle and behavioral details, and then sent out follow-up questionnaires by email every two months for 12 months, or until a woman became pregnant.

At the study's start, the women were asked about the average number of hours per week they exercised and about what types of moderate or vigorous physical activity they performed. Running, fast cycling, aerobics, gymnastics and swimming were considered vigorous. Brisk walking, leisurely cycling, golfing and gardening were defined as moderate.

The participants were categorized by their exercise levels and the results were evaluated according to body mass index (BMI, a ratio of weight to height). A BMI over 25 is considered overweight or obese.

While moderate physical activity was linked to becoming pregnant faster across all BMI ranges, the researchers found that there was an "inverse association" between vigorous physical activity and how long it took to become pregnant for normal-weight women (a BMI under 25). In overweight or obese women, there was no link between vigorous exercise and a longer time to pregnancy.

The study findings, which did not prove a cause-and-effect relationship, were published March 15 in the journal Fertility and Sterility.

Wise noted that in other research, being overweight or obese has been associated with lower fertility rates compared to normal-weight women. Obesity has also been associated with menstrual cycle disturbances. She said increased physical activity in this study might reverse the harmful effects of obesity and improve the overweight women's overall fertility rates.

The exact mechanisms for why physical activity might enhance fertility in overweight and obese women remain unclear, though, and the researchers didn't delve into them, Wise said.

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.

More information

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, Fertility and Sterility

Copyright©2010 ScoutNews,LLC.
All rights reserved

Related medicine news :

1. Exercise Success for People Over 50: Reports of Improved Fitness, Circulation and Balance
2. American Council on Exercise (ACE) Study Reveals Kettlebells Provide Powerful Workout in Short Amount of Time
3. In Support of the Lets Move Campaign to Fight Childhood Obesity, Verizon Thinkfinity Providing Free Educational Resources on Nutrition and Exercise
4. Beat The Odds and Get Back on Track; Revitalizing Fitness Training and Exercise Resolutions With Newly Released, Complimentary Video Series
5. Is Your Exercise Routine Killing You?
6. Exercise helps protect brain of multiple sclerosis patients
7. Teens Might Exercise More If They Think Its Fun
8. Labopharm announces underwriters exercise of over-allotment option for recent public offering
9. As Temperature Plummets, Its Still Safe to Exercise
10. Exercise Can Quiet Anxiety That Comes With Illness
11. Obesity, Lack of Exercise Heighten Arthritis Risk for Women
Post Your Comments:
(Date:11/24/2015)... ... November 24, 2015 , ... The ... waive paid entry and parking fees at several of their most popular properties, ... Great Barrington in support of REI’s Black Friday #OptOutside Campaign. The Trustees encourage ...
(Date:11/24/2015)... ... November 24, 2015 , ... In response to recent news ... deaths from prescription opioids in the United States grew 400 percent between 1999 and ... opioids were involved in 37 percent of all fatal drug overdoses. (1) , While ...
(Date:11/24/2015)... ... November 24, 2015 , ... Cancer patients, survivors, caregivers, ... at a live taping of the next CURE Connections® video series ... Cancers 2015 Symposium at Georgetown University Hotel & Conference Center in Washington, D.C. ...
(Date:11/24/2015)... AL (PRWEB) , ... November 24, 2015 , ... American ... announced today the opening of a holiday pop-up clinic located in Metro Atlanta’s North ... needs in a new and different way. The location is scheduled to operate through ...
(Date:11/24/2015)... ... November 24, 2015 , ... With Thanksgiving right around the ... safety tips to help protect your family and vehicle. , According to the National ... Thanksgiving holiday weekend. Amica is sharing the following safety tips from the NHTSA: ...
Breaking Medicine News(10 mins):
(Date:11/24/2015)... 24, 2015  Figure 1, a free mobile-first network ... cases, has launched a new completely redesigned web version ... allows radiologists, who work primarily on a desktop, to ... with its radiologist user base, Figure 1 is hosting ... North America (RSNA) Annual Meeting. ...
(Date:11/24/2015)... , Nov. 24, 2015  Family Rentals, a ... announced the launch of their newly designed, mobile-responsive ... --> Logo ... --> --> Now, renting essential ... and vacation, just got a whole lot easier ...
(Date:11/24/2015)... The uptake of recently approved and pipeline premium products for Type 1 ... 2021, says GBI Research . --> ... Diabetes Mellitus (T1DM), will be a key driver of market growth to ... The uptake of recently approved and pipeline premium products for Type ... to 2021, says GBI Research . ...
Breaking Medicine Technology: