Word: egges
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...make matters worse for the aging female, the eggs that remain in her ovaries get older and less fertile with each passing year. Recent studies of egg donation provide strong evidence that it is the age of the eggs, and not the age of the reproductive system, that causes fertility to decline sharply after age 40: older women who receive eggs from younger women get pregnant at rates comparable to the age of the egg donor, not the age of the recipient...
...ranging from laser-beam surgery to inflating a tiny balloon within the clogged passage. Men with extremely low sperm counts can be helped toward fatherhood by artificial insemination, which puts what sperm they have directly into the cervix, or by microinjection, which puts a single sperm right into the egg. And for couples with sperm-allergy problems, a procedure known as sperm washing strips the sperm of some of the chemical antigens that trigger the allergic reaction...
Scientists attribute the implantation rates of GIFT to the way in which the fertilized embryo enters the uterus. In IVF the embryo is squirted, rather violently, into a reproductive tract that has been pretty roughly treated, first by various hormone treatments, then by the egg-retrieval procedure. In GIFT, by contrast, the embryo drifts quietly into the uterus, much as it would naturally. To further improve the success rates, Asch's researchers tried fertilizing the egg in a lab dish and then placing the pre-embryo, or zygote, directly into the Fallopian tube -- a procedure known as ZIFT (zygote intra...
...latest clue in the mystery of implantation was hit upon by scientists working on a completely different problem: lazy sperm. Some sperm lack the ability to penetrate the egg's outer membrane, or zona pellucida, often as a result of old testicular injuries or early exposure to toxic chemicals. Several methods have been devised to give these sperm a boost, including microinjection (the sperm is inserted directly into the egg by means of a microscopic needle) and partial zona drilling (a tiny hole is made in the egg's protective shell...
...while working with patients with severe sperm deficiencies that researchers noticed something surprising. Eggs whose shells had been poked open were doing a much better job of sticking to the uterus wall. In a trial performed by Dr. Jacques Cohen, one of the scientists who developed the PZD procedure, embryos successfully lodged in the womb at a rate more than five times the national average for IVF. "I was so excited I couldn't sleep at night," says Cohen. Apparently eggs with a hole in their outer membrane somehow benefit from that hole. Cohen theorizes that embryos that...