DNA screening trial OK’d for in vitro embryos

Kyodo, JIJI

The Japan Society of Obstetrics and Gynecology on Saturday approved a three-year clinical trial to see whether screening embryos produced through in vitro fertilization can improve the birthrate by detecting chromosomal abnormalities.

The research on pre-implantation genetic screening, or PGS, is expected to begin in fiscal 2015 starting in April at six to 10 facilities approved by the society.

In vitro fertilization is on the rise as the nation struggles to halt a declining birthrate and shrinking population.

The society bans PGS because of concerns its use might lead to eugenics and the screening of lives. It has issued special approval for screening only for clinical research purposes.

If screening is shown to be effective, the society plans to encourage public debate on whether it should be approved for general use, officials said.

Chromosomal abnormalities are suspected of playing a role in infertility and repeated miscarriages. The incidence of chromosomal abnormalities is higher among older women, who also constitute a large percentage of those attempting to become pregnant through assisted conception.

However, because the screening will check all the chromosomes in fertilized eggs and only normal eggs will be implanted, critics say the method will allow parents to reject would-be children with certain kinds of chromosomal abnormalities such as Down syndrome or Turner syndrome, which alters the development of female embryos.

If the trial is effective, the head of the society’s ethics panel, University of Tokushima professor Minoru Irahara, said there will be a need to consider the method from an ethical perspective.

The clinical research trial will check fertilized eggs for chromosomal abnormalities using a technique known as array comparative genomic hybridization.

In the study, 300 women will undergo pre-implantation screening. Of that group, 200 have failed at least three times to conceive via in vitro fertilization, and 100 have suffered miscarriages at least twice.

Their results will be compared with those of 300 women who underwent ordinary in vitro fertilization and embryo implantation, bringing to 600 the total number involved in the study.

The pregnancy and childbirth success rates will be compared between the two groups over three years.

Health checks will be conducted on babies born to women participating in the study until the children enter elementary school.

Medical specialists will offer the couples counseling before and after the screening.

The participants will pay for the costs of both the in vitro fertilization and PGS.

Since 2004, examining fertilized eggs for chromosomal abnormalities has been conducted on a case-by-case basis in Japan. The practice has been limited to when a woman has the possibility of delivering a child with a serious genetic illness, or has experienced repeated miscarriages because of abnormalities in chromosomal shape.

In 2013, however, a new type of prenatal diagnosis became available in which a fetus’ chromosomal abnormalities can be checked with great accuracy by examining the blood of a pregnant woman.

At its board meeting the same day, the society also decided its ethics panel should review the recent decision recommending young and healthy women not preserve eggs for future pregnancy via freezing, due to health risks and the low success rate.