Girl meets boy. Girl marries boy. Girl and boy have a baby. For many folks, this is how they envision their life will be—or at least some sort of semblance of these milestone events—but for a large number of people, this has become an unattainable reality. According to the Centers for Disease Control and Prevention, about 7.3 million women between the ages of 15 and 44 suffer from infertility, which is defined as the inability to get pregnant after six to 12 months of trying. And while a woman's increasing age is the most familiar reason for this condition—more and more women are waiting to have children—researchers are discovering that there are new and once-unconsidered factors at play. And men are not exempt from this pregnancy problem, as one-third of infertility issues stem from the male partner. Here are some of the latest findings and what doctors say you can do in response to them.
Move in moderation and watch your weight. We all know that movement does the body good, but recent research suggests that too much of a good thing can be a hindrance. A study published in March in Fertility and Sterility revealed that normal-weight woman—those with a body mass index (BMI) under 25—who engaged in vigorous exercise like running, swimming, and aerobics for five or more hours a week were 42 percent less likely to get pregnant than women who did not exercise at all. "Very vigorous exercise can affect ovulation, and thereby disrupt menstrual cycles," says Jessica Scotchie, a reproductive endocrinologist practicing in Chattanooga, Tenn. "The pituitary gland interprets the strenuous exercise as meaning that this is not an optimal time to further stress the body with reproduction, and thus shuts down the signaling to the ovary to promote ovulation." Researchers also add that extreme exercise could affect implantation, a fertilized egg's ability to attach to the inside of the uterus.
The same study, though, found that this high-intensity exercise had no impact on conception for overweight or obese women. In fact, it may be beneficial, as obesity is linked to significantly higher rates of infertility. "Obesity is associated with high sugar levels, which promotes elevated insulin secretion from the pancreas. [This] causes increased testosterone production from the ovary, resulting in irregular menstrual cycles," explains Scotchie.
Although the study did not analyze men, doctors say the correlation between obesity and infertility in males is no different. According to Zamip Patel, an andrologist at Florida Hospital in Orlando, "The problem with moderately to obese patients is that fat cells contain aromatase. [Because of this enzyme,] some of the testosterone they produce is being converted to estrogen, and that is artificially telling the pituitary gland that there is too much testosterone. The pituitary responds by telling the testes to decrease the production of testosterone, thus decreasing the amount of sperm that is produced."
Apparently, less-intensive exercises like walking, leisurely cycling, and gardening are good for everyone. The Fertility and Sterility study showed a slight increase in fertility rates in women of all body types who engaged in moderate activities for any length of time. Given the exercise level of the average woman, says Scotchie, exercise for 30 to 60 minutes a day is unlikely to have a detrimental impact on the ability to conceive. In fact, "it's more likely to help with weight loss or maintenance, which helps conception and ensures a more healthy pregnancy." And, adds Patel, "the key is a slow burn, since too rapid a weight loss can decrease sperm counts."
Cut back on caffeine. A lot of us like an extra cup of joe or can't resist that supersized soda, but if you're trying to get pregnant, it's usually a good idea to say no. "There appears to be an association between excess caffeine intake and infertility, miscarriage, and pregnancy complications," says Serena Chen, director of reproductive medicine at Saint Barnabas Medical Center in Livingston, N.J. A lab study on female mice—they're reproductively similar to humans—published in 2011 in the British Journal of Pharmacology discovered that caffeine (the equivalent of two cups of coffee) reduced the muscle activity in the fallopian tubes, which aids in the transport of a woman's eggs from her ovaries to the womb. The caffeine caused the muscle contractions to lax, so much so that the eggs couldn't move.
Other studies have also demonstrated a link between caffeine and infertility. A report published in 1998 in Reproductive Toxicology revealed that women who drank between 300 to 700 milligrams of caffeine a day suffered a 12 percent lower chance of achieving pregnancy. Drinking even more lowered the chance of conceiving by 37 percent. And in 2008, Dutch researchers announced that in their study of nearly 9,000 women with fertility issues, those who drank four or more cups of coffee, or some other kind of caffeinated drink, on a daily basis were 26 percent less likely to get pregnant. "We're relatively conservative and recommend a limit of 50 mg of caffeine a day," says Chen, "which means one 6-ounce cup of brewed coffee or two teas. Decaffeinated drinks should be okay, but the healthiest thing to drink is water, and lots of it."