Birth Defects From IVF Down, Study Finds
Babies born via in vitro fertilization typically have a higher risk of birth defects, but a new review of the defect rates across Western Australia show that the major birth defects are becoming rarer. Researchers published the results in the journal Obstetrics & Gynecology.
"Changes to clinical practice may be largely responsible with improved (laboratory techniques) leading to the transfer of 'healthier' embryos," Michele Hansen, the lead author of the study and a researcher at the Telethon Institute for Child Health Research in Subiaco, Western Australia, told Reuters.
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It is not known why babies born through assisted-reproduction technologies (ART) have an increased risk of birth defects, but a recent estimate found that ART is linked to a 37 percent increased risk. However, researchers wanted to update that risk, and decided to take a look.
Researchers found that major birth defects, such as cleft lip, hip dysplasia and malformations of the heart, abdominal wall and genitals affected 8 percent of babies born via ART, compared to 5 percent of babies born via natural means.
However, when they looked at the rates between 1994 and 1998 and again between 1998 and 2002, researchers found that the rates dropped precipitously. In the first time period, 11 percent of babies born via ART had a birth defect. In the second, the rate dropped to 7.5 percent.
"It is very difficult to assess the impact of each of these changes on birth defect risk, however, we believe that changes to laboratory practice...changes to the medications used for ovarian stimulation requiring lower doses and shorter stimulation periods; together with a decrease in the number of embryos transferred may all have had a positive impact on the 'health' of embryos transferred in ART treatments," Hansen told Reuters. "Whilst our study does still show that babies born using Assisted Reproductive Technology remain at a higher risk of birth defects, couples seeking ART treatment can be reassured that the vast majority of ART infants are born healthy and do not have a birth defect."
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