How much do you really know about conception and staying fertile? If you're like most of us, it's far less than you think. In fact, when it comes to enhancing our fertility, many people have a lot to learn, says Pamela Madsen, executive director of the American Infertility Association (AIA). Her organization sponsored a recent Web-based survey on the subject. The results were startling: Only one in more than 12,000 women could answer 15 questions about their reproductive life cycle! Here are eight surprising fertility facts that every couple should know.
Thayer Allyson Gowdy
Overall good health isn't necessarily a sign that you (or your partner, for that matter) are fertile.
You exercise regularly, eat a nutritious diet, and have enviable cholesterol and blood pressure levels. That's great, but it doesn't mean you're fertile. One in 10 healthy couples of reproductive age will experience fertility problems. The causes are variable and equally attributed one-third of the time to the female, one-third of the time to the male, and one-third to unidentifiable reasons or to both partners. Unfortunately, the biggest factor that impacts fertility is something none of us can control: age, says Sam Thatcher, MD, a reproductive endocrinologist at the Center for Applied Reproductive Science in Johnson City, Tennessee, and author of Making a Baby: Everything You Need to Know to Get Pregnant (Ballantine, 2000).
For healthy women, fertility peaks in their mid 20s, begins declining at age 27, then nosedives around age 37. If you are in your mid 30s or older and trying to conceive, you need to be very pointed in your efforts, Dr. Thatcher advises. That means figuring out when you're ovulating and having sex at those optimal times. And if you're over 35 and concerned about your fertility, don't settle for a gynecologist saying "Just give it time," cautions Dr. Thatcher. The American Society of Reproductive Medicine advises women age 35 or older to consult a fertility specialist if they fail to get pregnant after six months of unprotected intercourse. Women ages 37 to 40 should wait no longer than three months.
Your weight affects your ability to conceive.
Surprise! Twelve percent of all infertility cases are rooted in weight issues. If your body is chronically malnourished or overexercised, you can't menstruate, since a minimum of 22 percent body fat is necessary for normal ovulation and reproductive competence. On the other side of the scale, being overweight can alter hormone chemistry and help prevent ovulation. The good news is that shedding or gaining pounds can easily remedy weight-related infertility; more than 70 percent of women conceive spontaneously once they reach healthy weight parameters. Doctors consider a body mass index (BMI) between 19 and 25 ideal. (BMI = weight in pounds divided by height in inches, divided by height in inches again, multiplied by 703. Example: 135 pounds, divided by 66 inches, divided by 66 inches, multiplied by 703 = BMI 22.)
Weight not only potentially impacts fertility but pregnancy as well. According to the March of Dimes, overweight women who become pregnant are at greater risk for pregnancy-related high blood pressure and diabetes, and underweight women are more likely to deliver a low birth weight baby. If you are at a reasonable weight and trying to conceive, now is not the time to begin training for a marathon or go on a crash diet.
Sexual positions -- coital or postcoital -- don't affect your chances of conception.
No study has confirmed that one position is more effective than any other in achieving pregnancy. In fact, sperm can be found in the cervical canal mere seconds after ejaculation, regardless of position. Of course, aiming for the deepest penetration and maximum cervical contact makes sense, but the optimal position varies because every woman's body is different.
And since sperm start swimming immediately after ejaculation, it isn't necessary for a woman to become a gymnast or a yoga master to make a baby. There may be a little advantage to lying around after intercourse to keep the sperm inside you, but there's absolutely no value in standing on your head, says Dr. Thatcher. So savor the mood however you please.
The biological clock ticks for men too.
The notion that age-related fertility decline is only a female factor has been debunked by a recent British study. Researchers at Bristol and Brunel Universities evaluated 8,500 couples to determine the impact of age on the length of time it took to conceive. They discovered that while only 8 percent of men younger than 25 fail to impregnate their partner after a year of trying, that number grows to 15 percent after age 35. Despite other factors, such as the fact that frequency of intercourse drops off with age, the study suggests that paternal age, too, may be a consideration for couples struggling with infertility.
Ovulation day is not necessarily the best day to try to conceive a child.
Sperm can live in the female reproductive tract for up to three days after intercourse, so having sex every day, or even on ovulation day, is not necessary. What is critical is knowing when you are fertile. According to data from the AIA, 20 percent of couples seeking infertility treatment are not timing intercourse correctly.
A woman is fertile for a period of six days, the five days leading up to ovulation (when the egg is released from the ovary) and the day of ovulation. A study by the National Institute of Environmental Sciences found, much to the researchers' surprise, that a woman 's capacity to conceive seems to end on ovulation day. So if women charting their basal body temperature are waiting for their temperature to go up to have intercourse, they're too late, warns Melissa Holmes, MD, associate professor of obstetrics and gynecology at the Medical University of South Carolina in Charleston. She recommends using ovulation kits because they let you know when you're about to ovulate. Having sex on the two days prior to ovulation offers the greatest chance of conception.