This prospective cohort study within the Gen3G (Genetics of Glucose Regulation in Gestation and Growth) was published in the Frontiers in Endocrinology journal. The number of pregnant women participating in the study was 1,024. Data was collected in the first and late second trimester of pregnancy. During the first trimester, general data such as BMI, age, and demographics were collected. Additionally, plasma miRNA was measured.

In the late second trimester, a 75 g oral glucose tolerance test (OGTT) for fasting 1 and 2 hours was performed. Further insulin and glucose levels were measured. Matsuda index for insulin sensitivity and Stumvoll first phase index for insulin secretion were computed. GDM was diagnosed with IADPSG criteria. At the time of delivery, general parameters of the newborn were recorded, and placental tissue (with decidua) was collected within 30 min of delivery for placental miRNA testing.

Higher insulin secretion was linked to a lower risk of GDM. Specifically, women with high insulin had a 50% lower chance of developing the disease. Two miRNAs were consistently associated in both the placenta and plasma. These were hsa-miR-199a-3p/199b-3p and hsa-miR-3150b-3p. hsa-miR-199a-3p/199b-3p had a positive correlation with insulin secretion, whereas hsa-miR-3150b-3p had a negative correlation with it. There is no practical evidence, but computational studies reveal that hsa-miR-3150b-3p targets phospholipase A, which is a crucial factor in insulin secretion.

These miRNAs are shown to influence insulin secretion, thus indicating the risk of GDM. Incorporation of these molecules as diagnostic markers can help in the effective management of GDM.