Baby girl created using new lab technique

Jul 3 2007

Canadian researchers have scored a world first by creating a baby from an egg which matured in the laboratory, was frozen, thawed and then fertilised.

The resulting baby girl was born in Canada and three more women are now pregnant by the same method.

The new method spares women from taking risky fertility drugs that can cause a rare, yet deadly condition - ovarian hyperstimulation syndrome (OHSS).

At a fertility conference in Lyon the researchers from the McGill Reproductive Center, Montreal said until now it was not known whether eggs obtained in this way could survive thawing to be fertilised.

They say the pregnancies are an exciting step and offers women with cancer-related fertility problems hope as the technique removes the risk of overstimulating women with hormone drugs.

As chemotherapy can cause infertility, some women with cancer make the decision to have their eggs collected and frozen before they start their cancer treatment.

However not all women will want or have the option of delaying chemotherapy in order to undergo ovarian stimulation and certain tumours, including some breast cancers, can flourish if the woman takes drugs to stimulate the ovaries.

Dr. Hananel Holzer and colleagues say the technique, in vitro maturation (IVM) has not yet been tried on women with cancer.

For the research the eggs were matured in the laboratory for between 24 and 48 hours and 215 were frozen for a few months.

Once thawed, 148 eggs survived and 64 were implanted in the women.

Dr. Holzer believes that the success rate can be improved by adjusting the substance the eggs are matured in.

The twenty women studied suffered from polycystic ovarian syndrome (PCOS), a condition where the ovaries are covered in cysts which can impair fertility and which is linked with an increased risk of OHSS.

Of the 20 women, four achieved pregnancy with the technique.

Dr. Holzer says it was unknown whether the oocytes collected from unstimulated ovaries would survive the process, be fertilised successfully and result in a viable pregnancy after embryo transfer but he does warn the research is still in its infancy.

Experts say though each step had been achieved before, this is the first time they have been successfully pulled together and it will expand the choices available to women with diseases of the ovary or cancer.

Others say the pregnancies are an exciting step but the pregnancy rate is very low and large numbers of eggs would be needed and they point out that the treatment is suitable for people with fertility problems linked to conditions such as PCOS or cancer, and not for women who merely want to delay having a family.