Women who seek treatment for infertility have a "reasonable" chance of having a baby with their own eggs in their early 40s, but success rates drop to close to zero once they reach age 44, a new study suggests.

Researchers reviewed birth outcomes among 1,263 women over the age of 40 treated at a large infertility clinic in Boston. After three attempted high-tech infertility treatments, birth rates for women 40 years old were 25 percent. By age 43 the corresponding birth rate was around 10 percent, and by 44 it was 1.6 percent.

For women who became pregnant with these high-tech procedures, the miscarriage rate per cycle was 24 percent for 40-year-olds, 38 percent for 43-year-olds, and 54 percent for 44-year-olds.

The findings are published in the August issue of the journal Fertility and Sterility.

"A woman in her early 40s has a reasonable chance at pregnancy with IVF, assuming that she is still having regular periods and [is still releasing eggs]," researcher Sigal Klipstein, MD, tells WebMD. "But by 44 the fertility window is definitely closing."

Late Motherhood Emerges

Successes Few After 43

Klipstein says the media focus on the seemingly endless parade of 40- and even 50-something celebrity new moms has helped to give women a distorted view of their fertility.

She adds that she routinely sees women in their mid-40s who mistakenly think that they are good candidates for IVF because they exercise, eat right, and still menstruate regularly.

A reproductive endocrinologist who now practices in Chicago, Klipstein conducted the study while completing her training at the infertility clinic Boston IVF, where the study participants were treated.

"The reality is that fertility drops dramatically after age 40," she says. "Even though we can bring that up a notch with IVF, by age 45 the chances are not very good," she says.

Myths, Dos and Don’ts for a Healthy Pregnancy

One in Five Patients Over 40 Seek Treatment

Almost one in five women who seek treatment for infertility in the United States today are over the age of 40. According to figures from the American Society for Reproductive Medicine (ASRM), one-third of those attempting pregnancy over the age of 35 will have trouble getting pregnant, and two-thirds will not be able to get pregnant on their own once they are past age 40.

As early as 15 years before menopause, a woman's ability to become pregnant declines. Egg production starts to decline and more of the eggs she does produce contain chromosomal problems that make infertility, miscarriage, and birth defects more likely.

This "double whammy," as Klipstein calls it, leads to a precipitous drop in fertility after age 40. But up until about age 43 fertility rates still differ dramatically from woman to woman, depending on ovarian reserve.

Infertility specialist Michael Soules, MD, tells WebMD that a woman's best predictor of fertility in her early 40s is her mother's age at menopause. Soules is managing partner for Seattle Reproductive Medicine and a former president of ASRM.

"If your mother entered menopause at age 50 that is a good sign that you will retain ovarian function longer," he says. "But there are no guarantees."

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What About Those Celebrity Moms?

Just seven women in the study were over the age of 45 when they entered treatment, and none of them achieved a successful pregnancy.

In recent years the number of women giving birth in their mid- to late-40s has doubled in the U.S., but Klipstein says this rise reflects the increased reliance on donor eggs.

"The media convey the message that pregnancy in your mid-40s is no big deal, because this celebrity mom is giving birth at age 47 and that one is giving birth at 50," she says, adding that a successful medically assisted pregnancy over age 45 almost always involves a donor egg.

A woman in her early 40s, using her own eggs, has about a 7 percent to 10 percent chance of getting pregnant with high-tech infertility treatments and a 50 percent to 80 percent chance if she uses a donor egg.

Bonding With Baby Before Birth

Don't Delay Treatment

Klipstein and Soules agree that the main message to women who want to have children after 40 is don't wait too long before seeking help.

"Younger women have the luxury of waiting, but we recommend that women over 40 who haven't gotten pregnant on their own in six months seek treatment," Klipstein says.

Though live birth rates have increased slightly in recent years among women in their early 40s using their own eggs, Soules says it is unlikely they will rise much more.

"The clear message is don't delay a month longer than you can help it if you are approaching 40," he says. "And don't think you are the exception that proves the rule. That is dangerous thinking."

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By Salynn Boyles, reviewed by Brunilda Nazario, MD

SOURCES: Klipstein, S.Fertility and Sterility, August 2005; vol 84: pp 435-445. Sigal Klipstein, MD, Boston IVF, Waltham and Harvard Medical School, Boston. Michael Soules, MD, managing partner, Seattle Reproductive Medicine.