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Fertility and your biological clock

Does a woman’s span of fertile years have a much later expiration date than medical experts used to believe?

Maybe so, but one thing hasn’t changed: Mother Nature is still timing your fertility with her biological clock. A recent study shows that, in most healthy women, fertility begins to slip away after age 25. At age 39, your chances of conceiving are only half that of when you were in your early 20s—your peak fertility years.

The odds diminish further if your spouse is older than 35. That’s the age when his ability to procreate begins to fade, the study notes.

Tick tock, tick tock

True, age no longer presents as many obstacles to pregnancy as it once did. Thanks to better healthcare, more and more women are delaying pregnancy in favor of a career or simply enjoying their independence. The average age of first-time moms is inching upward—it’s now 25—while the number of first-timers ages 40 to 44 has nearly doubled since 1981.

But each passing year still makes the odds more challenging and increases certain age-related risks to mom and baby, including:

Miscarriage. By her late 30s, a woman’s chance of miscarrying is double that of a woman 15 years younger.

Chromosomal abnormalities. At age 24, a woman’s chance of having a baby with Down syndrome is one in 1,300; by 40, it’s one in 100.

Birth defects. A 35-year-old woman has a five-in-1,000 chance of having a baby with a birth defect; by age 40, it’s 15 in 1,000.

Diabetes and hypertension. Later maternal age increases the mother’s risk of developing gestational diabetes and high blood pressure—conditions that could predispose her to diabetes and heart problems later in life.

Fatigue. Doctors say the “fatigue factor” increases with maternal age, for physical reasons as well as the fact that women in their 30s and 40s tend to be busier and have more responsibilities.

But wait, there’s more

Fertility in your later years can also be impacted by factors that affect moms of all ages, such as:

Smoking. Women who smoke lower their fertility by 20 percent and have higher rates of ectopic pregnancy and miscarriage. What’s more, women who breathe secondhand smoke have greater difficulty getting pregnant than those who avoid smokers.

Endometriosis. In this disorder, endometrial tissue from the uterus blocks the fallopian tubes, preventing the passage of eggs from the ovaries.

Estrogen. Obesity can elevate naturally produced estrogen levels, thereby inhibiting monthly ovulation.

Vegetarianism. Some vegetarian women have erratic menstrual cycles and ovulation patterns.

Prenatal prep

To cut the risk of fetal neural tube defects, researchers say women should begin taking 400 micrograms of folic acid daily several months before pregnancy. Ask your doctor about other preconception vitamin needs and food choices, such as increased intake of fruit and vegetables and less fat.

Follow his or her advice regarding scheduled office visits, tests, diet, weight gain, exercise and signs of fetal distress. Ask questions and provide information about your lifestyle, allergies, prescriptions and family medical histories.

Remember, prenatal preparedness involves a thorough physical exam and counseling. Be sure to schedule an appointment with your physician.

Fertility myths

Some notions about fertility and difficulty becoming pregnant that have no medical merit:

It’s usually the woman’s fault. In fact, 35 percent to 40 percent of the time it’s the man’s fault; 10 percent to 20 percent of the time it’s a shared problem; and 10 percent of the time fertility problems can’t be explained.

Stress causes infertility. Actually, it’s the other way around. Fertility problems aren’t “mental.”

More means better chances. Intercourse every two days before and during the “fertility window”—a six-day period leading up to the day you ovulate—is adequate in most cases. Check with your doctor if you haven’t gotten pregnant after 12 months (six months if you’re older than 35) and for help in finding your most fertile days. Most women ovulate around the 14th day of a normal 28-day menstrual cycle.

You can always get pregnant again. Not necessarily. Having had a baby doesn’t exempt you from the irreversible effects of the biological clock.