NEW YORK, Dec 28, (RTRS):Being physically active while pregnant may help women gain a little bit less weight, according to a new review of recent research.

Pooling the results of 12 studies, researchers in Munich, Germany, found that women who exercised while pregnant gained an average of 1.3 fewer pounds than women who didn’t.
That alone is probably not much of an incentive for women who are considering exercising while pregnant, but there are other reasons to do it, said Dr Michael Kramer of McGill University in Montreal who reviewed the findings for Reuters Health.

Research shows that exercise can have positive effects on mood and insulin sensitivity in people overall, and appears to have no negative effects on women during pregnancy, noted Kramer, who is also scientific director of the Institute of Human Development, Child and Youth Health at the Canadian Institutes of Health Research.

Exercise can also help women maintain their pre-pregnancy conditioning.
“Women who have been physically active can continue, and women who haven’t can start,” Kramer said. “But they shouldn’t expect major outcomes for them or their baby.”
Women who gain too much weight in pregnancy are at risk of a number of problems, including diabetes, high blood pressure, and labor complications.

A recent study also found that women who gained more weight during pregnancy gave birth to heavier babies, who in turn are themselves more likely to become obese adults. They also may be more prone to cancer, allergies, and asthma.

To investigate if exercise programs help women avoid the trouble that comes from too much weight gain, Ina Streuling of the Ludwig-Maximilians University of Munich and colleagues reviewed data from 12 studies that looked at the effect of an exercise intervention on women during pregnancy.
Collectively, the studies compared more than 1,000 women, some of whom were randomly assigned to follow an exercise program.

The programs encouraged women to exercise approximately three times per week, up to one hour of aerobics, running, biking or muscle strengthening, starting in the first or second trimester.
The studies did not uniformly show that exercise was associated with less weight gain in pregnancy, but overall, the data trend in that direction, said Kramer, who was not involved in the research review.
And some women lost more than the average of 1.3 pounds, Streuling told Reuters Health — specifically, women who were overweight or obese before pregnancy.

“To prevent high (weight gain), pregnant women should be physically active,” Streuling noted in an e-mail to Reuters Health.

The findings appear in the pregnancy journal BJOG.
They performed another analysis that included studies that combined physical activity and dietary counseling, and found women who followed this program gained almost three pounds less while pregnant.

Kramer co-authored a recent study that also reviewed previous research about the effect of exercise on pregnancy. That study “essentially found the same thing,” but the results were too weak to rule out whether the trend could have been due to random chance, not a true effect of exercise on pregnancy, Kramer noted.

It’s not hugely surprising that exercise alone would have only a small impact on weight gain in pregnancy, he explained — what really matters is not only how much women work out, but also how much they eat. “If you do a lot of exercise, you’re going to get hungrier. So unless you cut down on what you eat, you’re not going to lose weight.”

In addition, not all of the included studies were of high quality, Streuling noted, and some women not assigned to the exercise program may have been overall more active in their daily lives, which may also help explain why exercise appeared to have little effect on weight in pregnancy.

Even if exercise is generally safe in pregnancy, extreme contact sports and other intense exercise such as marathons and the Iron Man are probably not a good idea, added Kramer.

Hearing loss: Boys have been more likely than girls to show signs of a particular type of hearing loss, but girls are catching up — and the ubiquity of portable audio players may be to blame, new research suggests.
Hearing tests conducted on a national sample of teenage girls and boys showed that now roughly 17 percent - or 1 in 6 - of teens of both sexes have hearing losses that can make it harder for them to hear speech and some high-pitched sounds.

“The girls have kind of just caught up with boys,” study author Elisabeth Henderson of Harvard Medical School in Boston told Reuters Health.
The study, published today in Pediatrics, didn’t determine the cause of the hearing loss in girls, but one possibility, Henderson suggested, is that they are getting exposed to more loud noises.
Traditionally, boys were more likely to be exposed to loud noises from leaf-blowers, firearms, or work machines, Henderson noted - but today, more and more teens have portable music players, and both sexes are listening to loud music from headphones.
Indeed, the authors found that the percentage of teens who said they had listened to loud music through headphones in the last 24 hours increased from 20 percent in the late 1980s and early 1990s to 35 percent in more recent years.

The kids who reported recent exposures were no more likely to show signs of hearing loss, but it’s still possible that this increase in portable loud music is having an effect, perhaps explaining why girls have caught up to boys’ levels of hearing loss, Henderson said in an interview.
“We’re seeing a lot more kids being exposed to music recreationally,” she noted.
To investigate whether the recent popularity of portable music players is affecting teens’ hearing, Henderson and her colleagues looked at hearing tests collected from 2,519 teenagers between 1988 and 1994, and 1,791 teenagers between 2005 and 2006.

They considered three types of hearing loss: low-frequency loss, in which people struggle to hear sounds in the low end of the sound spectrum (such as parts of human speech); high-frequency hearing loss, which affects how well they hear high pitches (such as chimes or a microwave beep, or even kids’ speech); and noise-induced hearing-threshold shifts, or “NITSs,” in which people have trouble hearing sounds in the middle of the sound spectrum (which can include some human speech and higher-pitched sounds from musical instruments).

The investigators found that all three types of hearing loss were generally as common in the recent group of teens as they had been during the previous survey.
But when they looked more closely at the data, they saw that one group - teen girls - had experienced an increase in the rate of NITSs, from 12 percent in the first survey to 17 percent in the second.
Some form of NITS is permanent, and some is temporary, Henderson noted. “It’s impossible to tell.”
Henderson said she was not surprised they didn’t find higher rates of hearing loss now that more teens are listening to music through headphones. That’s because high-frequency hearing loss, for instance, comes only after years of exposure to loud sounds, so it would be unlikely in teenagers.

Even NITSs could become more common as teenagers age, she added. “It’s possible that teenagers, as they become young adults, will have even more hearing loss.”

There are several things teens can do to protect their ears, Henderson recommended. For one, they should always wear earplugs at loud concerts, buy environmental noise-canceling headphones, and keep the volume down. “A general rule of thumb is you should be able to hear someone talking to you even if you have your earphones on.”

Dr Peter Rabinowitz of Yale University in New Haven, who reviewed the findings for Reuters Health, agreed that the increase in hearing loss among girls is probably a result of exposures to loud sounds. “That pattern (of hearing loss) is pretty characteristic of noise-induced hearing loss,” he said.
But whether or not high volume from portable music players is to blame remains unclear, Rabinowitz added. More teens are listening to loud music, but most types of hearing loss didn’t increase, and boys were no more likely to have NITSs as they were in the previous survey.

“This study does not totally prove that loud music is causing hearing damage in kids,” he said.
But any diagnosis of hearing loss in teens is concerning, Rabinowitz noted. “We should be doing something to prevent it.”