The follow up showed that the women with high Hb levels had significantly higher rates of preeclampsia and GDM than those with normal Hb levels; the risks were 5.4 (95% cl; 2.8 to 10.5) and 3.7 (95%cl; 2.2 to 6.4), respectively. The gene discussed is GSTM1; the disease is gestational diabetes.