Childhood Obesity Could Increase Risk of Infertility for Women

By Mariah Pittman - Medical Research Editor | September 12th, 2012

The increase in childhood obesity in recent years has led to dramatic health concerns.

What if it could also lead to infertility later in life?

New research shows that childhood obesity can disrupt puberty onset and decrease the ability to reproduce, especially in women.

Ohio State University Assistant Professor Patrick Chappell, an author of a study on obesity and fertility published in Frontiers in Endocrinology, says, “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."

The trend of increasing obesity is related to another recent trend: the general acceleration of puberty, especially in girls.

In girls, this “precocious puberty” is defined as beginning before age 8. A 2010 review of 100 studies showed that overweight girls generally reach puberty before their peers.

So, what does a girl’s pubertal onset age have to do with having a baby down the road? Well, the effects of early puberty are numerous and long-term; reproductive cancers, adult-onset diabetes, and metabolic syndrome are but are few that seriously reduce reproductive ability. Early puberty can also disrupt the secretion of hormones necessary for reproduction and circadian clocks, which govern sleep cycles.

Hormone Secretion and Obesity:

The secretion of hormones by the endocrine system regulates body functions, such as metabolism, pubertal development, and reproduction. The liver, pancreas and other endocrine glands release hormones including testosterone, insulin, and kisspeptin—a neurohormone important for reproduction. When there is too much fat in the body, endocrine signals from the fat to the brain may disturb the normal release of hormones.

Chappell of Ohio University also believes that disrupted circadian clocks may be another link between obesity and infertility. “Disruption of the clock through diet can even feed into a further disruption of normal metabolism, making the damage worse, as well as affecting sleep and reproduction," says Chappell. Circadian clocks reflect natural day and night rhythms and a disruption to these clocks can disturb the secretion of hormones, having a domino effect on metabolism, pubertal onset and reproduction. The metabolic syndrome polycystic ovarian syndrome (PCOS) is caused by obesity and can greatly impact fertility.

Throughout the ages, mammals have decreased their fertility in times of starvation. Anorexic women often experience a lack of ovulation (anovulation) and menstruation (amenorrhea) until they regain weight. Until now, however, it was not thought that the other end of the spectrum—being overweight—could have similar detrimental effects on reproduction. If the reproductive trigger is not properly set at the time of a girl’s first menstruation, then anovulation can become a lifelong problem.

Obesity is a serious problem both for adults and children. Dr. Robert Matteri, director of Oregon Reprodive Medicine says, “Other direct side effects of obesity include diminished pregnancy rates and increased miscarriage rates compared to normal weight women.” Increased risk of adult onset diabetes, linked to early puberty and obesity, may also result in increased miscarriage rates and the risk of birth defects.

For those struggling with female infertility, there are answers. Egg donation from a suitable donor or in vitro fertilization (IVF)--when an egg is fertilized by sperm outside the body, are some options that a fertility specialist can explain to you.

The Final Word:

Is obesity behind difficulties conceiving? It could certainly be a factor, and it clearly poses health risks in both children and adults. To learn more about obesity and fertility, contact a fertility specialist near you.