A recent article reported in the New England Journal of Medicine May 7, 2012 has drawn a lot of media attention. This review of an Australian birth defect registry from 1986 – 1992 reported an increased rate of birth defects in children born from reproductive technologies. The percent of birth defects reported in this study in all populations evaluated, including the normal fertile population, was higher than many previous United States reports. This may mean that the Australian population reported in this study is not comparable to a typical U.S. population.
The Australian study reported that in a normal fertile population 5.7% of births had a birth defect. From the 1484 IVF births 7% had a birth defect. Very importantly the percent of birth defects reported in infertility patients who got pregnant on their own without any fertility treatment was 8.6%, higher than the rate of birth defects in IVF pregnancies. The rate of birth defects reported in ICSI pregnancies was 9.7%, or 1% higher than infertility patients who got pregnant on their own without fertility treatment. The overall risk of having a baby with a birth defect in frozen embryo transfer pregnancies was 7%, no different than fresh IVF cycles.
We have known for a long time that the most significant factor in predicting risk of birth defects is the age of the mother. This is because there is a higher percent of genetically abnormal embryos resulting from older women’s eggs. Most of these embryos do not implant (do not result in a pregnancy). Some result in early miscarriages, and still fewer result in genetically abnormal births. When comparing birth defects in an IVF population, IVF patients are generally older than a normal fertile population, and this must be factored into the analysis.
When looking at the implications of this study for women going through reproductive technology treatment, it is very important to compare the risk of having a baby with a birth defect to other infertile patients who got pregnant without fertility treatment, not to a normal fertile population. We have known for some time that women who have difficulty getting pregnant who then ultimately get pregnant on their own have a higher rate of birth defects. This suggests that something related to difficulty getting pregnant (? abnormal eggs or sperm)) in and of itself increases the risk of having a child with a birth defect, not necessarily related to the reproductive technology used in infertility patients to help them conceive. In this same study the percent of births with birth defects in women conceiving with intrauterine insemination (IUI) was also increased (9.3%), once again suggesting that the infertile population in general have a higher risk of birth defects however they conceive, on their own or with treatment.
This study does confirm other studies reporting that there is likely a small (1-2%) increased risk of having a child with a birth defect when ICSI is done. This may be due to the higher chance of abnormal genetics in sperm from men who require ICSI (male factor) for fertilization. Studies have reported that men with a severe male factor have a higher percent of chromosomal genetic abnormalities that can be passed on to their offspring. This does not mean that the ICSI technique itself is responsible for the slight increase in birth defects, so it is unknown as to whether there is any increased risk of birth defects if ICSI is done in men with fairly normal sperm.
Once again when considering this report of birth defects from reproductive technologies in an Australian population, you must compare those percentages to infertility patients conceiving on their own, not to the “general population.” When this is done it does not appear that there is a significant increase in the risk of birth defects with IVF. At the end of the day, anyone utilizing reproductive technologies to help them conceive must ask themself if a very slight increase in birth defects would prevent them from going through treatment that greatly increases their chance to become a parent.