Elevated maternal plasma homocysteine concentrations have been associated with adverse pregnancy outcomes, including birth defects, low birth weight, preeclampsia, spontaneous abortion, placental abruption, and other maternal or fetal complications. The purpose of this study was to assess the maternal plasma homocysteine level during pregnancy and to investigate the relationship between the plasma homocysteine concentrations and pregnancy outcomes. Venous blood samples were drawn from 82 pregnant women who were grouped with gestational age, 1st trimester (n = 26), 2nd trimester (n = 27) and 3rd trimester (n = 29). The concentration of plasma homocysteine was analyzed by HPLC, and pregnancy outcomes including gestational length, maternal weight gain, infant birth weight, and Apgar score were collected with the medical records of the pregnant women. The levels of plasma homocysteine of the pregnant women at the 1st, 2nd, and 3rd trimester were 5.7 $$pm$ 3.7mu㏖/L,;5.6 pm4.1mu㏖/L; and; 7.0pm 4.5mu㏖/L$</TEX>, respectively, which had not showed any significant difference. The result of this study showed that in case of the pregnant women at the 1st trimester, the maternal plasma homocysteine level of the pregnant women whose gestational length was less than 38 weeks was significantly high (p < 0.01) compared to that of the pregnants whose gestational length was more than 38 weeks. And also, the level of homocysteine of the pregnant women at the 2nd trimester was significantly low when the maternal weight gain was high (p < 0.05). These findings suggest that maternal plasma homocysteine level at early stage of gestation will be a predicter of gestational length and maternal weight gain.