In a nutshell
This study examined the risk of birth defects in children conceived with assisted reproductive technologies.
Previous studies have suggested that assisted reproductive technologies (ARTs) increase the risk of birth defects. ARTs include in-vitro fertilization (IVF), intracytoplasmatic sperm injection (ICSI), cryopreservation and medication to induce ovulation.
IVF involves the artificial matching of eggs and sperm in a laboratory dish. ICSI is a technique to directly inject the sperm into the egg. Cryopreservation is a method to quickly freeze and preserve fertilized eggs (embryos), sperm or testicular/ovarian tissue until they are needed for assisted reproduction.
Methods & findings
The present study analyzed data from a large birth registry in South Australia, which records the outcomes and complications of unassisted and assisted pregnancies. The collected data included 308,974 births, of which 6163 were achieved with ART. The risk of birth defects was compared between children conceived spontaneously and those conceived using ART. The risk was also compared between various ART methods.
Results showed that the percentage of birth defects was higher among children conceived using ART (8.3%) compared to those conceived without assistance (5.8%). The risk of birth defects was also found to be significantly higher among children conceived with ICSI compared to IVF alone. More birth defects were also found in single compared to twin pregnancies. Embryos that were cryopreserved were found to yield fewer birth defects. Medication to induce ovulation, such as clomiphene citrate, also increased the risk of birth defects.
The bottom line
These results suggest that ARTs are associated with a higher risk of birth defects compared to spontaneous pregnancies. ICSI using fresh embryos that were not cryopreserved seems to hold the highest risk but more research is needed to confirm these results.
The fine print
Although there is an increased risk of birth defects using ART, some may be diagnosed prenatally (before birth). These results were also obtained by analyzing data obtained indirectly, from a registry, which makes them less reliable.
If you are planning to become pregnant using ART, discuss all available methods and their relative risks with your physician. Knowing the risks should encourage individuals undergoing ARTs to perform all required follow-ups and prenatal tests and screenings.
Published By :
The New England Journal of Medicine
May 10, 2012