A Japanese woman who had been considered infertile has given birth after a team of Japanese and American researchers used a revolutionary procedure to reimplant her own ovarian tissue containing her own reawakened eggs.
In a study led by Kazuhiro Kawamura of the St. Marianna University School of Medicine in the city of Kawasaki, near Tokyo, a laparoscopic surgery was used to remove ovaries from 27 women who had gone through unusually early menopause that prevented them from conceiving. The women were all between their late 20s and early 40s.
The ovaries were preserved in liquid nitrogen. The researchers culled tissue from 13 of the ovaries that retained primordial follicles for two days after the surgical removal. The eggs nested within the follicles were awakened from a state of dormancy by bathing them in a solution. Small sections of tissue containing the eggs were then re-implanted near the upper reaches of the patients’ fallopian tubes.
Several weeks to a year later teams of Japanese and American researchers from Stanford University recovered mature eggs from from five of the patients. The eggs were artificially inseminated and implanted in the uteruses of three of the women. Two became pregnant. One — who had had her ovaries removed when she was 29 — delivered a baby boy at her current age of 31. The other pregnant woman is expected to give birth soon.
Premature menopause affects about 1% of all women and about 100,000 Japanese women, a somewhat higher percentage than the global average. The condition occurs when women stop menstruating before the age of 40 due to depressed ovary function. By puberty a healthy woman has about 500,000 immature eggs in their ovaries. One immature egg is normally released during ovulation which occurs about once every 4 weeks. By menopause most women retain several thousand immature eggs.
The breakthrough by the teams of Kawamura and Stanford’s Aaron Hsueh, the study’s senior author, essentially provides the means to use the remaining eggs to restore fertility for women whose onset of menopause had been premature.
The study was published in the September 30 issue of the US scientific journal Proceedings of the National Academy of Sciences.
