When stratified by type of diabetes, in pregnant people with type 1 diabetes, those with a ≥15% insulin drop had a significantly lower BMI (24.3 vs. 26.9 kg/m2, p = 0.029) and were less likely to be nulliparous (25.0% vs. 49.1%, p = 0.019), with no other significant differences. This evidence concerns the gene INS and type 1 diabetes mellitus.