It has been more than three decades since the very first “test tube baby” was born, and since that summer day in 1978, some three million babies have been brought into the world using assisted reproductive technology (ART). While the vast majority of those children are completely healthy, babies conceived using ART are generally at higher risk for a range of health problems than those conceived naturally, a discrepancy that prompted geneticist Carmen Sapienza from the Temple University School of Medicine, to analyze how genetic make-up may differ between these two groups.
In an article published in the January 1 issue of Epigenetics Sapienza writes:
“There is no question that the great majority of children conceived through assisted reproductive technologies appear normal at birth. However, as a group, these children are of lower birth weight and are more often born prematurely (even when multiple pregnancies are taken into consideration). These issues put some of these children at risk for development of systemic diseases such as obesity, hypertension and/or cardiovascular disease and possibly other ailments later in life.”
By analyzing a particular type of chromosome modification known as DNA methylation—which basically turns genes on and off—from 10 children conceived using IVF or other ART, and 12 children conceived naturally, Sapienza found that between 5 to 10% of chromosome modifications were different in the group born through assisted reproduction. Sapienza and colleagues say that it isn’t clear whether these variations are a result of ART conception, or perhaps due to the parents’ struggles with infertility. (Future research, he suggests, should analyze the genetic differences between children whose parents struggled with infertility as a result of physical problems, and those who struggled to conceive for other reasons.) Yet, because several of the genes impacted by these changes are associated with the body’s fat production and ability to metabolize sugar, Sapienza says future study should carefully monitor long-term risks for obesity and diabetes among people born using reproductive technologies.
Of course, while identifying the genetic “markers” associated with later health risks among children born through IVF or other types of reproductive technology could potentially open doors toward using these markers to intervene and prevent development of health problems, Sapienza was careful to emphasize that, even in light of the genetic differences, the ART-conceived children he studied were seldom outside of “normal” health and development parameters.
Sapienza’s latest findings were published in the journal Human Molecular Genetics and presented this past week at a meeting of the American Academy for the Advancement of Science in San Diego.