How is gene study adding to the overall knowledge of preterm birth?

The 2018 meeting of the American Gynecological and Obstetrical Society, held in Philadelphia, Pennsylvania, September 6 to 8, featured a talk by Louis J. Muglia, MD, PhD, on “Evolution, Genetics, and Preterm Birth.” Dr. Muglia, who is Co-Director of the Perinatal Institute, Director of the Center for Prevention of Preterm Birth, and Director of the Division of Human Genetics at the Cincinnati Children’s Hospital Medical Center, discussed his recent research on genetic associations of gestational duration and spontaneous preterm birth and some of his key findings. OBG Management caught up with Dr. Muglia on how he feels the study of the human genome could lead to advancements in the prevention of preterm birth.

OBG Management: You discussed the “genetic architecture of human pregnancy.” Can you define what that is?

The genetic architecture tells us which pathways are activated that initiate birth to occur. By understanding that, we can begin to understand not only the genetic factors that the architecture describes, but also that the genetic architecture is going to be modified in response to environmental stimuli that will disrupt the outcomes. In the future, we will be able to develop biomarkers, predictive genetic algorithms, and other tools that will allow us to assess risk in a way that we can’t right now.

OBG Management: How is gene study adding to the overall knowledge of preterm birth?

Gene study is giving us new pathways to look at. It will give us biomarkers; it will give us targets for potential therapeutic interventions. I mentioned in my talk that one of the genes that we identified in our recent New England Journal of Medicine (NEJM) study pinpointed selenium as an important component and a whole process of determining risk for preterm birth that we never even thought of before. For instance, could there be preventive strategies for prematurity, like we have for neural tube defects and folic acid? The possibility of supplementation with selenium, or other micronutrients that some of the genetic studies will reveal to us in a nonbiased fashion, would not be discovered without the study of genes.

OBG Management : You mentioned your NEJM paper. Can you describe the large data sets that your team used in your gene research?

The discovery cohort, which refers to essentially the biggest compilation, was a wonderful collaboration that we had with the direct-to-consumer genotyping company 23andme. I had contacted them to determine if they had captured any pregnancy-related data, particularly birth-timing information related to individuals who had completed their research surveys. They indicated that they had asked the question, “What was the length of your first pregnancy?” With this information, we were able to get essentially 44,000 responses to that question. That really provided the foundation for the study in the NEJM.

Now, there are caveats with that information, since it was all recollection and self-reported data. We were unsure how accurate it would be. In addition, we did not always know why the delivery occurred—was it spontaneous or was it medically indicated? We were interested in the spontaneous, naturally-occurring preterm birth. Using that as a discovery cohort, with those reservations in mind, we identified 6 genes for birth length. We then asked in a carefully collected series of cohorts that we had amassed on our own, and with collaborators over the years from Finland, Norway, and Denmark, whether those same associations still existed. And every one of them did. Every one of them was validated in our carefully phenotyped cohort. In total, that was about 55,000 women that we had analyzed and studied between the discovery and the validation cohort. Since then, we have accessed another 3 or 4 cohorts, which has increased our sample size even more, so we have identified even more genes than we originally reported in our paper.