Scientists induce egg growth in infertile women

Researchers have developed a new revolutionary technique to induce the ovaries of some infertile women to produce eggs.

One woman has already given birth to a healthy baby, and another is pregnant with the help of the technique developed by scientists at Stanford University and in Japan.

The technique, which the researchers refer to as "in vitro activation," or IVA, requires an ovary (or a portion of an ovary) to be removed from the woman, treated outside the body and then re-implanted near her fallopian tubes.

The woman is then treated with hormones to stimulate the growth of specialised structures in the ovaries called follicles in which eggs develop.

Using the technique, clinicians at the St Marianna University School of Medicine in Kawasaki, Japan, collected viable eggs from five women with a condition called primary ovarian insufficiency, which may cause them to hit menopause before they turn 40.

Twenty-seven women in Japan took part in the experimental study. The researchers were able to collect mature eggs for in vitro fertilisation from five of them.

The new study builds on earlier work demonstrating that a signalling pathway consisting of several proteins, including one called PTEN, controls follicle growth in the ovary.

In 2010, Aaron Hsueh, senior author of the current study, showed that blocking the PTEN activity in ovaries could stir dormant follicles into growing and producing mature eggs.
Researchers used minimally invasive procedures to remove both ovaries from each of 27 women with primary ovarian insufficiency.

The women's average age was 37, and they had stopped menstruating an average of 6.8 years prior to the procedure.

The researchers found that ovaries from 13 of the women contained residual follicles. The ovaries were mechanically fragmented and treated with drugs to block the PTEN pathway.

Small pieces were then transplanted laparoscopically near the fallopian tubes of the women from whom they were derived, and the women were monitored with weekly or biweekly ultrasounds and hormone-level tests to detect follicle growth.

Follicle growth was observed in eight of the women, all of whom had exhibited signs of residual follicles prior to transplantation.

These eight were treated with hormones to stimulate ovulation; five women developed mature eggs that were collected for in vitro fertilisation.

The eggs were fertilised with sperm from the partners of the women, and the resulting four-cell embryos were frozen and then transferred into the uterus.

One woman received one embryo but failed to become pregnant. Another received one embryo and is pregnant. The third received two embryos and established a successful pregnancy that resulted in a single, healthy baby boy.

The other two women are preparing for embryo transfer or undergoing additional rounds of egg collection.

The study was published in the journal Proceedings of the National Academy of Sciences.