In a small but provocative study, researchers found suggestions of abnormal brain development in the fetuses of obese women.
Specifically, researchers from the Mother-Infant Research Institute at Tufts Medical Center examined gene fragments (which can provide insight into fetal organ development, including the brain) in the amniotic fluid of both lean and obese women. As early as the second trimester, they detected differences in the gene expression in the fetuses of obese mothers compared to fetuses of women who were a healthy weight, they report.
The study only involved a total of 16 pregnant women, eight lean and eight obese.
Still, maternal obesity is a growing public health problem with 1 in 5 pregnant women in the U.S now obese. A whole host of health problems and complications have been linked to maternal obesity, including “higher rates of cesarean section, higher rates of infant birth defects and a three-fold higher incidence of neonatal death. Babies born to obese mothers, even if born at a normal weight, have been shown to have multiple metabolic problems with lifelong consequences,” according to the Mother-Infant Research Institute.
In this study, presented at the Society for Maternal-Fetal Medicine’s annual meeting in San Francisco last week, researchers reported that the fetuses of obese women had decreased apoptosis, a developmental process of programmed cell death. Andrea Goldberg Edlow, the study’s lead researcher and a fellow in Maternal-Fetal Medicine at Tufts Medical Center explained it this way: “One could think of apoptosis as being similar to necessary “pruning” or trimming away of excess material in the developing fetal brain. It is well-documented in animal models that apoptosis plays a critical role in brain development in utero.”
I asked Dr. Edlow a bit more about the research. Here’s what she emailed in response:
RZ: How did you actually see the decreased apoptosis?
AE: We didn’t actually *see* decreased apoptosis. Because these were living human fetuses, we could not perform stains or direct studies on their brains to actually observe decreased apoptosis. Instead, by examining the genes expressed in the amniotic fluid, we were able to observe an increase in expression of anti-apoptotic genes, and a decrease in expression in pro-apoptotic genes in fetuses of obese women.
We took a bioinformatics approach using publicly available databases, which utilize algorithms to predict dysregulated systems based on your gene expression data. Brain apoptosis was identified as being decreased by the bioinformatics database.
RZ: Can you hypothesize at all about the mechanism that might link the obese mother to this decreased function in the fetus?
AE: This was a new and unexpected finding, and we don’t really know at this point- further study is needed.
RZ: Can you describe some of the other neurodevelopmental abnormalities in children of obese women?
AE: [Senior researcher and executive director of MIRI] Dr. Diana Bianchi and I want to stress that we did not directly observe decreased apoptosis in the brains of fetuses of obese women, nor did we link this finding to any neurobehavioral abnormalities in the offspring of the specific women in our study.
Other large epidemiologic studies in humans have noted lower cognitive performance in children of obese women, as well as increased risk for autism spectrum disorders and developmental delay, and increased risk for attention deficit hyperactivity disorder. These large epidemiologic studies are not able to elucidate the mechanisms underlying these findings, only to demonstrate an association.
RZ: What’s the next step in this research?
AE: We plan to examine these findings further in a mouse model of maternal obesity.