TFF2 and gestational diabetes: Compared with healthy controls, the frequency of the SP-D 31Met/Met (T/T) genotype was significantly lower in GDM patients (P = 0.033), indicating that homozygous SP-D 31Met/Met (T/T) women are resistant to GDM incidence; the frequency of the SP-D 31Met/Thr (T/C) genotype was significantly higher in GDM patients than in healthy controls (P = 0.017), suggesting that heterogeneous SP-D 31Met/Thr (T/C) women are sensitive to GDM incidence (Table 2).