Test-tube technique `increases birth risks'

NICHOLAS TIMMINS

A new method of boosting the success rate of the test-tube baby technique looks to be increasing the risk of abnormal children being conceived, a team of obstetricians warn in the Lancet today.

The technique, known as ICSI (intra-cytoplasmic sperm injection) involves injecting the sperm directly into the egg in the laboratory, rather than simply mixing the two and allowing the egg to "choose" one of the sperms for fertilisation.

The technique is particularly used where the father has a low sperm count or other fertility problem.

In nature, the egg in some way "chooses" which sperm to admit of the millions with which it is normally presented, before it closes itself off to the others. It is assumed, though it is not known how, that in some way the egg is able to favour healthy sperm over those carrying the genetic information that can lead to birth defects.

Injecting the sperm directly into the egg by-passes that process. In today's edition of the Lancet, Dr Peter Int Veld and colleagues from the Erasmus University in the Netherlands report that routine checks on 15 pregnancies established using the technique have revealed five cases of sex chromosome abnormalities in the foetuses which led to abortions.

The finding ties in with another report and the doctors say that further studies are needed in order to establish just how frequently such abnormalities occur.