Insulin sensitivity or resistance in pregnancy can be estimated using insulin or C-peptide and glucose values at multiple time-points during the standard OGTT (e.g., using the Matsuda formula which has been validated in pregnancy); however, the studies that calculated insulin resistance using HOMA-IR, which simply requires fasting insulin and glucose values, found that this index was a marker for higher rates of LGA or macrosomia in women with GDM, making it an appealing simple biochemical marker115,121,124,126. The gene discussed is INS; the disease is Insulin resistance.