Introduction: Gestational Diabetes (GD) is a pathology characterized for hyperglycemia during pregnancy, which generates maternal-fetal and long-term outcomes^1-2. The rs9939609 polymorphism in the FTO gene could be a genetic risk factor to develop GD³, given its association with the body mass index, which has also been related to this pathology⁴.

Objective: To determine risk of develop GD in pregnant women from Concepción (Chile), associated with the rs9939609 polymorphism in the FTO gene.

Methods: DNA was extracted from blood samples of pregnant patients with and without DG. The rs9939609 polymorphism was genotyped by PCR-HRM. Odd Ratio (OR) was estimated with Fisher's exact test.

Results: The risk "A" allele in the rs9939609 polymorphism increases the risk of developing GD, in dominant model (OR (95% CI): 5.06 (1.29 - 19.77); p: 0.02), and in allelic model (OR (95% CI): 2.48 (1.06 - 5.79); p: 0.04). Also, carriers of the risk allele had significantly higher fasting and 2 h post-oral glucose load glycemic levels, during the second trimester of pregnancy (p: 0.03 and 0.02, respectively).

Conclusion: Women from Concepción (Chile), carriers of the risk “A” allele in the rs9939609 polymorphism, have higher risk of develop GD during pregnancy.