Stillbirth risk 'higher for women after IVF'

The risk of stillbirth is also four times higher with a procedure called intracytoplasmic sperm injection (ICSI), where the sperm is injected directly into the egg.

Experts studied the effect of IVF and ICSI compared with women who either got pregnant naturally or who had fertility treatment other than IVF or ICSI.

The results of more than 20,000 pregnancies of single babies were analysed, with a clear increased risk for stillbirth after IVF and ICSI.

The authors said more research was needed into the exact reasons, although the study suggests it may be the fertility treatments themselves that are responsible for the increased risk.

However, the authors, from Aarhus University Hospital in Denmark, said the chance of stillbirth was still very low.

A recent, larger study in Sweden found no link between IVF and increased risk of stillbirth.

According to Office for National Statistics data, there were 3,617 stillbirths in England and Wales in 2008, a rate of 5.1 per cent per 1,000 births.

The latest research, published in the journal Human Reproduction, looked at Danish pregnancies from 1989 to 2006.

The risk of stillbirth in women who conceived after IVF or ICSI was 16.2 per 1,000 women.

In fertile and sub-fertile women, the risk of stillbirth was 3.7 per cent and 5.4 per cent respectively.