After finding a willing donor–sometimes a friend or family member of the patient, sometimes a stranger who is paid for her help–doctors prepare both women for the transfer. The donor receives hormonal treatments to increase the number of eggs produced during her menstrual cycle. The recipient gets a different hormone regimen to prepare her womb for pregnancy. When the donor starts to ovulate, the doctors insert a needle through her vaginal wall to extract eggs from her ovaries. The eggs are then combined with sperm in a culture dish to create embryos, which can be inserted vaginally into the prospective mother’s womb. The patient typically receives three to five embryos, in the hope that one will develop. But pregnancy usually takes more than one try and can end in multiple births.
When this technique was introduced in the early ’80s, few experts thought it was worth pursuing in women over 40. But three years ago, when Dr. Mark Sauer of the University of Southern California treated seven women in their early 40s, four bore healthy babies. He has now treated more than 200 older women–including more than two dozen in their 50s–and roughly a third have eventually become pregnant.
When women over 40 conceive naturally, they’re four times as likely as younger mothers to die during delivery, and their babies suffer slightly increased rates of prematurity and stillbirth. But by using eggs from young donors, and screening the recipients for health risks, Sauer has found that over-50 mothers fare just as well as those in their 40s.
Ethicists are now debating the morality of a purported scheme to transplant ovaries from aborted fetuses into aging women. But physicians say that’s an unlikely prospect at best. No one knows whether fetal ovaries would mature normally outside the fetal environment, says Dr. Roger Gosden, the Edinburgh University researcher who raised the possibility last year. Nor is it clear that a woman’s body would accept the foreign organs. “I haven’t announced any intention to recover fetal ovaries,” Gosden says. “I’ve raised the possibility only because I think it should be looked at and regulated.”
Neither borrowed eggs nor transplanted ovaries are likely to revolutionize babymaking any time soon. Worldwide, fewer than 100 quinquagenarians have been impregnated with donor eggs. But egg swapping has given the pioneers a new option.
