‘Abnormal’ embryos in IVF should not be discarded, say studies

COUPLES having in vitro fertilisation (IVF) will have a greater chance of conceiving if embryos deemed “abnormal” are not discarded, research suggests.

Embryos with abnormalities are too readily removed from batches due to concerns that they will fail to implant or lead to a miscarriage, two studies claim.

These so-called “mosaic embryos” can still become healthy babies and fertility clinics should be braver in using them, as it increases the chances of success during IVF cycles, say scientists.

The New York University Langone Fertility Center and Igenomix studies were presented at the American Society for Reproductive Medicine last month.

The first involved 35 women being implanted with mosaic embryos. The foetuses were tested for chromosomal abnormalities at the end of the first trimester and none were found.

In the second study, scientists compared the outcomes during IVF of 484 embryos with normal chromosomes with 413 mosaic embryos. They found that the mosaic embryos were as likely to implant in the uterus as the normal embryos, and had the same likelihood of becoming a healthy baby.

Some 10 to 15 per cent of embryos are mosaic, which means their cells contain both normal and abnormal chromosomes. In IVF, embryos can be tested for mosaicism. Abnormal cells can increase the risk of the embryo failing to implant in the uterus, or miscarriage.

However, scientists point out that abnormalities in cells are very common in humans, and this is not always a valid reason to discount mosaic embryos.

They can also go through “self-correction”, in which abnormal cells begin dividing and eventually stop growing. This means a healthy baby can be born.

Dr Raj Mathur, of the British Fertility Society said testing embryos for abnormalities is offered by some UK fertility clinics, and patients should be given counselling to decide whether or not to use mosaic embryos in their IVF cycles.

Dr Ippokratis Sarris, of King’s Fertility, said: “We’re becoming more confident in putting back mosaic embryos. We would know if these people have problems by now. You either get miscarriages or healthy babies, because we don’t get mosaic people.”