Babies born after fertility treatment could be twice as likely to suffer from complications such as low birth weight, premature birth and neonatal death, a large-scale study has found.
Looking at births in South Australia between 1986 and 2002, researchers studied more than 300,000 women who had given birth to one child or twins. Two percent of these births resulted from assisted conception.
Of those who were spontaneously conceived, half of one percent of babies died within a few weeks of birth, while one percent of those born after fertility treatment died. Premature birth was also more likely following assisted conception: eight percent in women who had fertility treatment compared to 4.7 percent of naturally conceived children.
However, the study also showed that babies born from frozen IVF embryos were no more likely to be underweight or stillborn than those conceived naturally.
'Using frozen embryos eliminated all significant adverse outcomes associated with ICSI, [intracytoplasmic sperm injection] but not with IVF', said Professor Michael Davies from the University of Adelaide, who led the study. 'However, frozen embryos were also associated with increased risk of macrosomia (big baby syndrome) for IVF and ICSI babies'.
Professor Dagan Wells from the University of Oxford commented on the findings, saying: 'Although this study suggests that some adverse outcomes are higher in pregnancies conceived using IVF, it is important to understand that the overall risk of these problems remains low'.
It is possible that these complications arose as a result of women's underlying fertility issues rather than from IVF or other assisted reproductive technology. Women who were characterised as infertile but conceived naturally with no treatment were almost twice as likely to have a very low weight baby and almost three times as likely to have a stillbirth.
Sheena Lewis, professor of reproductive medicine at Queen's University Belfast, dismissed the results as 'bad science', saying: 'We have known for some time that couples conceiving spontaneously after a period of infertility have poorer outcomes. This indicates that these problems may come from the disease rather than the fertility treatment'.
Professor Wells agreed, adding: 'The problems seen for babies born after IVF may be related to the patient’s infertility rather than the treatment itself. In fact, for couples with reduced fertility, IVF seemed to lessen these risks compared to natural conception'.