Embryo screening test is 'safe'

In PGD, a cell is removed and examined for abnormality

An embryo screening test called pre-implantation genetic diagnosis (PGD) is safe for the children of singleton pregnancies, Belgian researchers say.

They looked at 581 children born at one Belgian centre over 13 years who had been screened using the PGD technique.

They found that rates of birth defects and deaths were similar to those of children born using other IVF methods.

However, significantly more deaths just after or before the birth were seen in multiple pregnancies following PGD.

The findings come after concerns that the PGD screening technique, which involves removing some of the embryo's cells at an early stage, could lead to problems.

But the researchers, writing in the journal Human Reproduction, found no significant difference in birth defect rates when compared to 2,889 children born using IVF but who did not undergo the screening.

More perinatal deaths

In total, 2.13% of PGD children had birth defects compared with 3.38% of the other children.

The perinatal death rate - the period immediately before and after birth - was also similar at just over 1% for singleton children in both groups.

However, for multiple pregnancies there was a difference. In the PGD group it was 11.73%, whereas among the others it was 2.54%.

Professor Inge Liebaers, head of the centre for medical genetics at the University Hospital Brussels, said:"At present, we don't have an explanation for why the perinatal death rate (for multiple pregnancies) should be so much higher in the PGD children, and we need to be careful about drawing firm conclusions from these observations as they may be biased due to low numbers.

"There is a need for more careful, thorough and long-term follow-up studies after PGD and the number of cases needs to be expanded.

"The parents-to-be need to be fully informed on the health of offspring.

"Unfortunately, funding for these studies is hard to find."

In an accompanying editorial, Professor Joe Leigh Simpson, of the Florida International University, said that Professor Liebaers' study was as good as it gets and showed that: "in experienced hands, removal of one (or more) blastomeres does not result in an increase in birth defects.

"Whatever the controversy concerning efficacy of PGD in increasing pregnancy rates, patients may be informed that PGD is safe."