My husband is 35 and I am 47, which makes our odds of healthy children low. My periods are regular and I have not started menopause. I have had two full-term births, but pregnancy was hard due to a condition in which my ovaries are surrounded with a coating. My physician explained that it was difficult for my ovaries to release the ovum easily. My daughter is willing to donate an egg for us. If we do this, are the odds against a healthy child still high even though the ovum would be from a younger donor?

D.B.

Assuming your daughter is the egg donor and not related by blood to your present husband, your odds of success should be considerably over 50 percent per attempt. The younger your daughter is, the better the odds. Egg donation offers many advantages to healthy women who -- due to age, ovarian surgery, radiation therapy, chemotherapy or unknown factors -- are unlikely to achieve a pregnancy using their own eggs.

You asked whether having an egg from a younger donor would increase your odds of a healthy child. The answer is yes. The increased risk of Down syndrome and other defects related to maternal age relates to the age of the egg donor, not the person who carries the pregnancy. So your risk for age-related abnormalities would depend on your daughter's age, not your age.

After careful medical and psychological screening, treatment begins. The best results are achieved when your own periods are suppressed and we prime your uterine lining to accept the transferred embryos, with daily doses of estrogen at first and then a combination of estrogen and progesterone. While this is going on, your daughter takes injections of medications to stimulate the development of as many eggs as possible. Ultrasound and blood testing is used to determine when the eggs will be ready. She receives intravenous sedation; using ultrasound for guidance, the doctor removes the eggs from the ovary. They are mixed with your husband's sperm. Three to five days later, two or three embryos are transferred back into your uterus, where with luck at least one will take up residence for the next eight months or so. To learn more about in vitro fertilization, see my web page on IVF.