St. John's wort, echinacea, and ginkgo biloba are among the herbs that may affect the chances of conceiving, experts say. Men and women who are trying to become parents should be wary of any herbal supplements and should talk to a specialist before using them.
According to the American Society for Reproductive Medicine, 6.1 million American women and their partners experience difficulty in conceiving a child. And the most recent estimates show that as many as 60 million Americans reach for herbal remedies on a regular basis.
"Many herbal preparations have been documented to contain estrogenic substances, which can have an impact on sex-hormone concentration and fertility in both males and females," says Gilbert Ross, MD, medical director of the American Council on Science and Health in New York. Estrogen is the major female sex hormone.
Richard Blackwell, MD, an obstetrician/gynecologist at the University of Alabama at Birmingham says in a prepared statement that echinacea and ginkgo biloba may hurt sperm production and fertilizing capability.
But buyers should beware of all herbal supplements, cautions fertility expert Masood Khatamee, MD, a clinical professor of obstetrics and gynecology at New York University and the executive director of the Fertility Research Foundation in New York.
"None of these herbs have been studied. Be very cautious when using them," he tells WebMD.
"Patients need to be aware that herbal supplements are medicine and can have an impact on your treatments," says Pamela Madsen, executive director of the American Infertility Association, a national nonprofit group headquartered in New York. "No patient should be taking herbs while undergoing infertility treatments without talking to their doctor."
Other factors known to affect fertility in men and women include the following:
- Cigarette smoking. While the exact way in which smoking impairs fertility is unknown, some research suggests that smokers may have a greater risk of failing to ovulate. A study from the Berkeley University School of Public Health shows that smoking substantially interferes with women's ability to become pregnant. Smoking less than half a pack a day led to an approximate 50 percent reduction in fertility at the end of one year, the study showed.
- Vaginal lubricants. "Many lubricants kill sperm and can thus affect fertility," Madsen says. "Studies have consistently shown that these compounds are deleterious to sperm [movement] and viability," Blackwell adds.
- Age. "For women, advancing age is the most important factor affecting fertility," Khatamee says. "Deciding when to seek help with fertility depends on age. If you are between 20 to 30 years old, wait a year, but if you are older, seek advice after three months." Men, too, are affected by advancing age. A study in a recent issue of the journal Human Reproduction found that a man's odds of getting his partner pregnant in a given year of trying fall by about 3 percent annually after age 24.
- Choice of underwear. "We know that if men are wearing tight briefs, it brings their testicles close to the body. You are heating [the testicles] up, which kills the sperm and thus, impairs fertility," Madsen says. Bicycle riding and spending too many hours behind the wheel may also affect male fertility, some new research suggests, because heat may build up in the scrotum, the pouch that contains the testes and related organs.
- Weight. Obesity, as well as dramatic weight loss and excessive exercising, can hinder fertility in women, Madsen says. For example, when a woman loses an excessive amount of body fat, her hormones -- and thus her fertility -- are affected, Khatamee explains.