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Childhood Obesity Could Lead to Adult Infertility
by Leigh Ann Woodruff, August 10, 2012
According to the American Heart Association, in the United States, one in three children ages 2 to 19 are overweight, and one in six are obese, which means their body mass index for their age is at or above the 95 percentile of the Centers for Disease Control and Prevention (CDC) growth charts. Not only is this concerning because overweight and obese children are more likely to stay this way into adulthood and develop diseases such as diabetes and heart disease at younger ages, but they are also more likely to have reproductive problems.
A recent report published in Frontiers in Endocrinology suggests that the dramatic increase in childhood obesity is related to growing problems with infertility. From1980 to 2008, the percentage of U.S. children ages 6–11 years who were obese increased from 7 percent to nearly 20 percent, and the percentage of adolescents ages 12–19 years who were obese increased from 5 percent to 18 percent.
"It certainly adds to the already numerous adverse health problems associated with obesity," says Robert Matteri, M.D., a fertility doctor and medical director of Oregon Reproductive Medicine. "Anovulation is probably the most common side effect of obesity itself. If the reproductive 'thermostat' is not set properly at the time of menarche, something that usually happens only with thin women like athletes, then this could be a lifelong problem even with further weight loss."
The researchers at the University of Oregon who published that analysis of a body of research say that in terms of evolution, the obesity problem is a new one, and human bodies are scrambling to catch up. In the past, poor nutrition and starvation were the human bodies' primary concerns, not overabundance of food. And metabolic syndromes caused by obesity, such as polycystic ovarian syndrome (PCOS), can have a significant impact on fertility.
"The issue of so many humans being obese is very recent in evolutionary terms, and since nutritional status is important to reproduction, metabolic syndromes caused by obesity may profoundly affect reproductive capacity," says Patrick Chappell, an assistant professor of veterinary medicine at Oregon State University and an author of the recent report.
Girls are experiencing puberty earlier, which is also linked to childhood obesity. "Precocious puberty" is defined as puberty beginning before age 8 for girls, and a 2010 review of more than 100 studies found that overweight girls tend to reach puberty earlier than their peers do. Researchers are still learning about the effects of obesity on the beginning of puberty and on the liver, pancreas and endocrine glands. There are theories that fat has an effect on kisspeptin, a hormone necessary for reproduction, by disrupting normal secretions of the hormone.
In addition to problems with fertility, early puberty has been linked to reproductive cancers, adult-onset diabetes, and metabolic syndrome. "Other direct side effects of obesity include diminished pregnancy rates and increased miscarriage rates compared to normal weight women," Dr. Matteri says. "The increased risk of developing adult onset diabetes could result in more miscarriages and even results in an increase in birth defects if the diabetes is not controlled.
"The increasing numbers of young woman who now start off their reproductive period in life overweight or with actually obesity will clearly lead to a reduction in their fertility and an increase in pregnancy complications if they do conceive," Dr. Matteri continues. "Hopefully, as more information about the effects of obesity on reproduction become published, like from these researchers at OSU, young women — and when they are just teenagers, their families — will have even more motivation to control weight gain."
The bottom line: Being overweight is bad for your fertility if you are an adult and your future fertility if you are a child. For more information on weight and fertility risks, read: