Hello dear I understand your concern Duvadilan and methylcobalamin is safe during the pregnancy. Duvadilan contains Isoxsuprine. It is a β2 adrenoreceptor agonist that causes direct relaxation of uterine and vascular smooth muscle via β2 receptors. It prevent the threatened abortion. Mrethylcobalamin, pyridoxine and folic acid will help in the growth of the baby as nutrient supplements. So just be relax and take it under the advice of treating OBGYN specialist. Calcium generally given in the 2nd and 3rd trimester. Avoid stress, take healthy diet and proper bed rest. Hope this may help you Contact HCM for further health query Best regards Dr. Sagar