IVF babies are twice more likely to die in their first week than those conceived naturally, finds study
Babies who are born via in vitro fertilization (IVF), among other assisted reproductive techniques, have a higher risk of dying during the first weeks of their life than children conceived naturally, according to a large study on 2.8M children.
Researchers from Karolinska Institutet in Sweden also found that the children conceived through IVF had a 45% higher risk of death before 1 year of age than children conceived naturally.
The level of risk varied depending on which type of assisted reproductive technique was used, and how many days had passed since birth. The risk gradually reduced after the first weeks of life, says the team.
According to the researchers, one explanation might be that more IVF-children are born prematurely than those conceived naturally, which in itself could have negative consequences. It is also possible that the underlying infertility leads to a higher risk of complications.
The leading causes of infant mortality among children conceived with assisted reproductive techniques included respiratory distress, incomplete lung development, infections, and neonatal hemorrhage, which are conditions often linked to prematurity, say experts.
The team, however, emphasizes that the risk of infant death is still very small for both groups. Beyond 1 year of age, the risk of mortality was similar for all children regardless of conception method, they explain.
"It is important to note that even if we on a group level can see a somewhat increased risk of infant mortality after IVF, the absolute risk for each individual is still very small. It is also reassuring to know that there is no increased risk of mortality in this group of children beyond the first year of life,” says Kenny Rodriguez-Wallberg, associate professor at the Department of Oncology and Pathology at Karolinska Institutet, in the analysis.
The researchers selected only single children for their study and compared mortality in children conceived through different types of assisted reproductive techniques with children who were conceived naturally. They analyzed data on 2.8M children born in Sweden over a period of 30 years. Some 43,500 of these were the result of assisted reproduction.
The analysis shows that in all, 7,236 children died before 1 year of age, of whom 114 were conceived with assisted reproductive techniques.
After adjusting for confounding factors such as the mother's age and earlier infertility, it was found that the IVF-children had a 45% higher risk of mortality during the first 12 months, says the study published in Fertility & Sterility.
The analysis reveals that during the first week of life, the children conceived after the transfer of a frozen embryo had a more than two-fold higher risk of death than the children conceived naturally. This was, however, based on only a small sample of children conceived with frozen embryos.
“After one week, the risk dropped to about the same level as the naturally conceived children. Infants conceived from the transfer of a fresh embryo or with the help of an intracytoplasmic sperm injection (ICSI) -- where a single sperm is injected into the egg -- did not have a higher risk of death than naturally conceived children, irrespective of how many days had passed since birth,” the findings state.
Based on their findings, the researchers recommend the need for extra attention and care of children conceived with IVF, especially during the first week of life.
According to them, the results show that the type of assisted reproductive technique used may make a difference. Therefore, says the team, it is important to further investigate what causes or underlying mechanisms are behind the risks.