What Causes Secondary Infertility?
The decline in fertility between a first and a hoped-for second pregnancy can often be chalked up to age. A woman's most fertile years are between ages 15 and 30, with a drop-off occurring at 30 and a quite precipitous plunge at 35. (In fact, by 36, almost 25 percent of women may already be infertile.) Many women are unaware of this reality and delay first-time pregnancy until 30 or beyond. That means they are even older when seeking a second. It is thought that a woman's eggs suffer chromosomal damage as they age; the older the eggs, the more damaged they are, and the less likely they are to become fertilized or go to term.
Passing time also means that other conditions, not specifically age-related, can develop where they didn't previously exist. Hormonal shifts or other endocrine problems can crop up, altering the body's delicate balance. And endometriosis, an ailment in which the uterine lining attaches itself to other pelvic organs, worsens over time if left untreated, creating tubal blockages that prevent conception or cause ectopic pregnancies. (The latter occur when the fertilized egg implants itself somewhere other than the uterus -- usually in the fallopian tube, which may rupture and need to be surgically removed).
Male-factor causes -- low sperm count or poor sperm motility -- are the culprit in about 40 percent of infertility cases. Occasionally, the change in a man's fertility can be traced to a chronic illness such as hypertension or diabetes, explains Esther Eisenberg, M.D., director of the Reproductive Endocrinology and Infertility Center at Vanderbilt University Medical Center, in Nashville. Excessive alcohol consumption or moderate marijuana use can also impair male fertility.
More often, though, the reason for the change simply can't be pinpointed, making the diagnosis especially bewildering. "We had a child, so we expected the test to come back fine," says Tara Jenkins, 23, from Mitchell, Indiana, who took a year to conceive her 3-year-old daughter. "It was a real blow to find out that my husband had a low sperm count."
Hidden scars are another possible cause. Untreated infections (after a D&C, for example, or childbirth) can leave abnormal tissue in the uterus. These adhesions may prevent a fertilized egg from implanting properly or create scarring in the fallopian tubes, which keeps an egg from reaching the uterus. A new mother may develop an infection without realizing it, Dr. Eisenberg says. A woman who's never had a baby before can be completely unaware of how much postpartum pain or bleeding is normal, and many women have symptoms of infection they never report. Their diminished fertility won't be discovered until they try to conceive again.
Sandy Mott, 36, of Sterling, Virginia, easily became pregnant in 1991 and 1993 and seemed to sail through both deliveries. Mott's doctors now believe, however, that she suffered an undiagnosed infection following the birth of her second son. The resulting scars contributed to an ectopic pregnancy in 1998 that went undiagnosed until it ruptured a fallopian tube; a second ectopic pregnancy was caught early and removed. Because of scar tissue in her one remaining tube, an expensive in vitro fertilization (IVF) procedure was Mott's best option. After one failed IVF attempt, Mott and her husband were ready to call it quits but decided to try again when they got new health insurance with some infertility coverage. This time, the procedure worked, and the couple's third son was born last June.
But the most common diagnosis by far -- in as many as 20 percent of all cases -- is simply "unexplained infertility." In other words, says clinical psychotherapist Harriet Fishman Simons, Ph.D., author of Wanting Another Child, Coping With Secondary Infertility (Jossey-Bass), "there's no diagnosis at all. It's not clear whether some factor has been in existence all along and the couple was just lucky or whether the factor has become exacerbated over time." Because it is so vague, the "no known cause" verdict can be particularly hard to accept: "After all, these parents have living proof of their fertility," Dr. Simons says.
"Our two older children were conceived with barely a thought," says Ellen Rosenblum, 37, of Aurora, Colorado. "How were we to know that the third time would be so different?" After trying to conceive for eight months, she and her husband underwent fertility testing, without clear results. Although the couple eventually had a third child, now 6 months old, "it was incredibly frustrating," Rosenblum says. "When there's a diagnosis, at least there may be a treatment plan."