Birth defects appear to be higher in IVF babies, according to a review of many studies. In vitro fertilization (IVF) is the process, which has been in use for several decades, in which an egg is fertilized by sperm in a lab.
The research, published in the journal, Fertility and Sterility, revealed that babies conceived through certain fertility techniques are at about a one-third increased risk for being born with a birth defect versus babies conceived naturally, said Reuters. The team reviewed several dozen prior studies.
The team did not determine if technology was involved in the increased risk and why such treatments lead to increased risks, noted Reuters. Led by Zhibin Hu at Nanjing Medical University, the team reviewed 46 studies in which the number of birth defects in IVF babies was compared to babies conceived naturally. Of the over 124,000 babies born via IVF or ICSI, birth defect risks were 37% greater than in other children, wrote Reuters. ICSI involves fertilization of an egg via injection of a single sperm and has long been the main method used to overcome male infertility. If successful fertilization occurs, the embryo is then placed into the female via IVF. Fertilization, not necessarily pregnancy, rates are relatively high when ICSI is employed.
“Children conceived by IVF and/or ICSI are at significantly increased risk for birth defects, and there is no risk difference between children conceived by IVF and/or ICSI,” the team wrote, said Reuters. The U.S. Centers for Disease Control and Prevention (CDC) notes that major birth defects occur in about three of every 100 babies born in the U.S. An 37% increase would raise this to four of every 100 babies, noted Reuters. Birth defect risk was seen across a span of functions and body systems, such as the genitals, skeleton, digestive system, and nervous system, the authors wrote. “(The report) confirms what most people accepted anyway, that, yes, there is an increased risk in congenital abnormality associated with assisted reproductive technology,” said William Buckett, a professor at McGill University, according to Reuters. Buckett was not involved with the review.
Some theories for the increase include that the issues tied to infertility might influence the likelihood of giving birth to a baby with a birth defect, that IVF techniques could be involved, or that IVF babies are more closely monitored, Reuters reported. “It is really too early to find out ways to reduce the risk, because the reasons accounting for the risk are largely unknown,” said Hu in an email.
We previously wrote that IVF babies seem to experience an increased risk for childhood cancer, versus babies conceived naturally, according to prior Swedish research. That study was believed to be the first of its kind to indicate a scientifically strong link, said the American Society for Reproductive Medicine in 2010. IVF babies were 1.4 times or 40% likelier to have experienced cancer in the research’s follow-up period, which ended in 2006.
We also wrote that birth defect risks appeared to be twice as high in babies conceived via fertility treatment, versus babies conceived naturally, according to French scientists. Assisted reproductive technology (ART) treatment includes infertility treatment methods such IVF and ICSI. We also previously wrote, citing Reuters, that women who undergo IVF or ICSI and who become pregnant, experience an increased risk of giving birth to a stillborn baby, according to Danish scientists.
In 2008, we wrote that Chinese researchers reported that the use of IVF or ICSI to conceive appears to increase the odds of Y-chromosome defects or microdeletions in male offspring, meaning that chromosomal defects, or deletions, could result in defective sperm production and possibly hypospadias, a congenital malformation of the male sex organs in which the urinary outlet, or urethra, does not open through the glans of the penis, but develops on the penis’ underside.
Prior research has linked ARTs with low birth weight, pre-term delivery, cerebral palsy, and major birth defects. Because of this, some researchers believe that such therapies may prompt gene mutations. Reuters said that a 2009 study revealed that babies born worldwide via ART increased to 246,000 annually in 2002 from 219,000 in 2000.