The prevalence of GDM was significantly increased in women with PCOS compared to healthy controls, and some studies have found that phenotype A may be more likely to lead to GDM. Risk factors were similar to pregnant women with only GDM, but with GDM and PCOS specifically, preconception low sex hormone-binding globulin, increased BMI > 25 kg/m2, and preconception impaired glucose tolerance were specific. The gene discussed is SHBG; the disease is polycystic ovary syndrome.