In vitro less effective after 40, study finds

WASHINGTON – In vitro fertilization, which thousands of women undergo each year in the hope that it will give them the same odds of having a baby as when they were younger, cannot fully reverse the biological clock, researchers are reporting today.

A study involving more than 6,000 women who underwent IVF at a large Boston clinic found that while the treatment could give infertile women younger than 35 about the same chance of having a baby as women typically have at that age, it could not counteract the decline in fertility that occurs among those past 40. It is the largest study of its kind to assess the chances that women of various ages undergoing IVF will go home with a baby.

“Even as effective as IVF is, it can’t reverse the effects of aging,” said Alan Penzias of Harvard Medical School, who led the study published in the New England Journal of Medicine. “We cannot reverse the biological clock.”

In addition to providing women with a more accurate estimate of their chances of having a baby through IVF, Penzias said he hoped the study would help dispel common misconceptions about women’s fertility.

“One of the sad states of affairs is that there are many women who are not aware that there is an effect of aging,” Penzias said. “Women feel otherwise healthy. They may be able to run the Boston Marathon. They may be at the peak of their career. … But meanwhile their fertility is potentially slowly ebbing away year by year.”

More than 113,000 IVF treatment cycles are performed each year, and the number has been increasing steadily, in part because of women delaying childbearing for their careers or other reasons. About 10 percent of IVF cycles are done on women age 40 and older.

The procedure, which costs about $12,000 per attempt, can be physically and emotionally grueling.

Women undergo several weeks of hormone injections to stimulate the ovaries and a sometimes-painful surgical procedure to remove the eggs, which are fertilized in the laboratory to try to create viable embryos. If that works, embryos are then transferred into the woman’s womb in the hope that at least one will produce a live baby. The process often requires several cycles, forcing women to endure an emotional roller-coaster.