Some IVF Births Followed by Natural Conception
The couple had tried for six years to have a baby. Repeated medical tests showed no obvious cause for their infertility. Finally, they underwent in vitro fertilization and had a lovely baby boy.
Then, 11 months later, they had a lovely baby girl.
The boy’s conception was the result of much planning and agonizing and $10,000 worth of medical treatment. His sister’s birth followed a surprise conception that cost nothing.
How did it happen?
An eye-opening new study that may alter the advice given to infertile couples shows that conception can occur the natural way in as many as 18% of women--particularly younger women--after they have given birth through IVF.
Studies on fertility among couples after they give birth via IVF treatment are rare. The study in the January issue of Fertility and Sterility (the official journal of the American Society for Reproductive Medicine) puts numbers on a phenomenon that infertility doctors say they have long observed.
Researchers in Japan followed 142 women, ages 24 to 40, after they gave birth by IVF. The couples involved all had one or more types of infertility: endometriosis, an overgrowth of uterine tissue that can prevent pregnancy; mild male factor infertility, in which the male’s sperm is problematic; or the causes of their infertility weren’t obvious.
The couples had an average length of infertility of five years before undergoing IVF, and most had two IVF treatments before getting pregnant.
Despite their earlier difficulties, 25 of the 142 women were able to conceive naturally within five years of having a child through IVF. Most of those became pregnant within two years of the IVF-assisted birth.
The results varied significantly depending on the women’s age. Among women younger than 27, the rate of spontaneous conception was 37%. Women older than 34 had only a 10% chance of conceiving spontaneously.
There are no obvious reasons to explain these couples’ good fortune. But, according to several theories, pregnancy and childbirth may “cure” endometriosis to some extent, thus allowing for spontaneous conception.
“It may be that pregnancy does have a beneficial effect on endometriosis,” said Dr. Arthur L. Wisot, of the Reproductive Partners Medical Group in Los Angeles and author of the book “Conceptions and Misconceptions.”
Wisot notes that IVF was created specifically for women with blocked or damaged tubes, and who cannot conceive without assistance.
“The only patients [spontaneous conception] happens to are people who have endometriosis or unexplained infertility. For people with blocked tubes or severe male problems, this won’t happen,” he said.
Among couples with unexplained infertility, the women may have mild endometriosis that is cured by giving birth. Couples in which the male partner was diagnosed with mild male factor infertility had a 20% rate of spontaneous conception after IVF.
The old idea that less stress promotes fertility might have some value, the authors note. “Long-standing infertility and infertility treatment are a significant source of stress.”
The study also shows how strongly age is linked to fertility. Despite some obvious problems, younger women still have a better chance of conceiving, said Dr. Benjamin Younger, executive director of ASRM.
A few decades ago, when couples typically started their families at much younger ages, “it was clear many of them [with infertility problems] would ultimately get pregnant on their own,” he said. And, in the early days of IVF therapy, when there were long waiting lists for treatment, it was common to see the younger patients become pregnant while they were still waiting.
“This study pretty well demonstrates the most important determination of whether a couple will get pregnant or not--and that’s the woman’s age,” Younger said.
The study’s authors, from the Akita University School of Medicine, Akita, Japan, say the findings suggest that doctors should alter their advice to women with these types of infertility diagnoses. When women in their 20s or early 30s conceive through IVF, they should be told to wait at least two years before attempting to have a second baby via IVF because nature might beat them to it.
The study doesn’t imply that the couples who conceived naturally after IVF should not have undergone the costly treatment in the first place, said Dr. Arthur Haney, past president of the ASRM.
“Normally, women in their 20s have a 20% chance of conceiving in any cycle in which they don’t use birth control. But these women in the study had gone for up to 60 cycles without becoming pregnant,” he said.
Still, women who don’t wish to have another child should consider using birth control--something many infertile couples don’t bother with.
“Doctors should tell them, ‘If you don’t want to be pregnant again, you should practice contraception,’ ” says Younger. “But I think most couples who have a baby through IVF would be happy to have another.”
