Higher Rate For Stillbirth With IVF

In vitro fertilization (IVF) is now said to increase the risk for stillbirth by more than four times that of natural conception, say researchers. Yet researchers still don't know whether it is the treatment that causes this state of affairs or some other factor that exists in couples undergoing treatment that is independent of IVF. This is according to Kirsten Wisborg, MD and her team at Denmark's Aarhus University Hospital.

The large-scale study has been published in the online medical journal Human Reproduction and reports on 20,000 Danish women who had singleton pregnancies between 1989 and 2006. However, this study follows a separate study published only a few short weeks ago which found no such association between stillbirth and miscarriage.

Karl Nygren, MD, PhD, of Stockholm's Sofiahemmet Hospital issued a statement, "The Danish study is interesting. [But] in Sweden we have been unable to confirm its findings in a recently published study of a bigger group of women."

No Difference

Nygren's team looked at the data on obstetric outcomes over a period of 25 years. The data collected by Nygren and his colleagues was from 27,386 women who gave birth after treatment with IVF. The Swedish team found no great difference between this group and that of the general population in terms of stillbirth rates.

But Wisborg argues that the differences between these two study populations, for instance factors such as smoking while pregnant, and possibly in the way the treatments were carried out might be the reason why these studies generated two very different sets of results. Wisborg gave a statement that suggests caution in attempting to bridge the gap between the varied sets of data from the Swedish and the Danish studies. Furthermore, both Wisborg and Nygren have stressed that the risk for stillbirth is still quite low, no matter whether a couple undergoes IVF or conceives their child without benefit of fertility treatment.

Hospital Records

Wisborg's study involved collecting information from the participants about reproductive treatment by dint of a questionnaire. The data on pregnancy outcomes, however, was taken from Danish hospital records. The women were divided into four groups: fertile, subfertile, those who underwent IVF or intracytoplasmic sperm injection (ICSI), and women who conceived by other types of assisted reproductive therapy, for instance ovarian stimulation and insemination.

The overall risk for stillbirth was found to be 4.3 in 1,000. But the risk in women who had undergone IVF or ICSI was 16.2 in 1,000 compared to 3.7 in 1,000 for the group of fertile women.