Frozen embryos help lower risk of defects

FREEZING embryos significantly decreases the risk of birth defects in assisted reproductive technologies (ART), Australian research shows.

In a study which also confirmed that intracytoplasmic sperm injection (ICSI) carries a higher risk of birth defects compared to in vitro fertilisation (IVF), researchers at the Robinson Institute, University of Adelaide, analysed data on nearly 309,000 births including 6100 births from ART.

Co-author Professor Eric Haan said when comparing fresh IVF and ICSI, IVF was 36% less likely to result in birth defects than ICSI.

“However, when the embryos were frozen the risks of birth defects in both procedures decreased significantly,” he said.

The researchers found an overall 8.3% risk of  birth defects with assisted conception compared to 5.8% risk for spontaneous conception.

The risk for IVF was 7.2% compared with 9.9% for ICSI.

“After... adjustment the association between IVF and the risk of any birth defect was no longer significant whereas the increased risk of any birth defect associated with ICSI remained significant,” the researchers concluded.

Professor Haan noted that women seeking ART were already at increased risk due to infertility.

N Eng J Med 2012; online 5 May