The first successful transfers of an embryo from one woman directly to another has been achieved by doctors in California.
According to their report in the British medical journal Lancet, they have achieved two pregnancies by the technique. One of the babies is due in four months, the other in seven months.
A different technique used by Australian doctors last March resulted in a pregnancy that lasted eight weeks, then spontaneously aborted.
"To our knowledge, this is the first report of established pregnancies after deliberate in vivo live fertilization of donor women, non-surgical recovery of fertilized ova eggs and transfer of those . . . ova to infertile women," the California doctors reported. John E. Buster of the Harbor-UCLA Medical Center in Torrance leads the team.
The technique of taking an egg from one female and transplanting it in another has been studied for years. It has become a relatively widespread method used on farm animals.
The technique may become very important to the estimated 2 million women in this country who have eggs but cannot become pregnant. When the new technique becomes more common, it will be possible for women to donate eggs, just as men now donate sperm to sperm banks for artificial insemination, which now results in 40,000 births annually in the United States.
Ethicists and lawyers have raised questions about the practice, however, because it is unclear legally who is the owner of the transplanted embryo and who is the biological mother of the child.
In the technique used at Harbor-UCLA, a woman is fertilized by artificial insemination while the egg is in her body. Five days after it begins to grow and divide, it is flushed out of the womb with a salty solution. The egg, which is now an embryo because it has been fertilized and begun dividing, is then implanted in another woman's womb.
Unlike most other parts of the body, the womb does not reject foreign tissue; it takes the transplanted embryo to be its own. The embryo implants itself and continues to grow.
In the technique used in Australia, the egg was fertilized "in vitro"--in a glass dish. After growing in a nutrient solution for several days, the egg was implanted in another woman.
In the Lancet article, the doctors said preliminary evidence indicated that the success rate of the UCLA embryo transfer "may be higher" than the 20 to 25 percent reported with "in vitro" fertilization because no surgical procedure is required to collect the egg. It is flushed from the womb. In "test-tube" fertilization and in the Australian method, the egg is surgically removed. About 125 test-tube babies have been born since 1978.
The names of the two women who are pregnant as a result of the UCLA implant method were not given in the Lancet article. However, it did say that the women's husbands had provided the sperm.
The California doctors said they had done 14 such inseminations, five of which resulted in conceptions and transplants. Three recipients did not become pregnant.
The doctors said the five who had transplants had undergone unsuccessful surgery for blocked Fallopian tubes.