Low birth weight may be linked to inadequate protein and vitamin B12 in the 2^nd and 3^rd trimesters of pregnancy.  There are epidemiological associations that have been noted for these deficiencies during pregnancy, but they have not been tested.  It is also thought that supplementing methionine and vitamin B12 would be beneficial to methionine kinetics and in consequence, favourably changing the epigenome of babies, with a view to preventing later chronic disease in adulthood.  Earlier studies have shown that methionine and arginine kinetics are low in Indian pregnant women.  This is particularly relevant with the thrust being given to the adequate and appropriate feeding of pregnant women in India.  To test the hypothesis that supplementation of protein and vitamin b12 during pregnancy could improve biochemical fluxes, placental epigenetics and birth outcomes, an intervention trial with a daily supplement of 500 ml of skimmed milk during pregnancy was performed in low BMI pregnant Indian women. Methionine and arginine kinetics were measured at the end of 1^st trimester and in 3^rd trimester, as well as birth outcomes and placental characteristics. The study findings will help in filling gaps in our knowledge about the relationship between nutritional status of pregnant women and maternal and child health outcomes. The novelty of this study is the use of stable isotope tracers that measures fluxes of amino acids, since we have earlier shown that arginine and methionine are deficient during pregnancy.