Objective: To evaluate the effect of folate and vitamin B 12 levels on pregnancy progression and outcomes. Methods: The present study is a prospective follow up study of 100 pregnant women. Biochemical investigations (plasma homocysteine, folate, and vitamin B 12 levels) were performed on all pregnant women in first, second, and third trimesters. Nonparametric tests were used to compare the differences in median levels and odds ratio analysis for the assessment of the risk between the selected biomarkers and adverse pregnancy progression and outcomes. Results: The pregnant women at their first antenatal care visit were found to be predominantly folate replete (97%) and vitamin B 12 deficient (60%). Hyperhomocysteinemia in first and second trimesters was found to pose more than 3-fold increased risk for adverse pregnancy outcomes (P = .006 and .0002, respectively). Low birth weight (LBW) was found to be the most common adverse pregnancy outcome (52%), and was significantly associated with vitamin B 12 deficiency in the first and second trimesters (82%, P < .0001; 71.4%, P = .04, respectively). Conclusion: The vitamin B 12 deficiency is more common among Indian pregnant women as compared to folate deficiency. Hyperhomocysteinemia is an independent risk factor for pregnancy complications. Vitamin B 12 deficiency in first and second trimesters is associated with LBW babies.