<prompt> Use of folic acid to prevent congenital malformation should be best initiated :During 1st trimester of pregnancyDuring 2nd trimester of pregnancyDuring 3rd trimester of pregnancyBefore conception  <response>: Ans. is d i.e. before conception Folic acid has been shown to effectively reduce the risk of neural tube defects NTDs. A daily 4 mg dose is recommended for patients who have had a previous pregnancy affected by neural tube defects. It should be staed atleast 1 month ideally 3 months prior to pregnancy and continued through the first 6-12 weeks of pregnancy. Remember : Folic acid is used to reduce the risk of neural tube defect Therapeutic dose of folic acid to be given in females with previous history of baby with NTD - 4mg. Prophylactic dose of folic acid - 0.4mg i.e. 400 mcg Duration :It should be staed 1 month before conception and continued till first 6-12 weeks of pregnancy. Note : Women with insulin dependant diabetes mellitus and those with seizure disorders treated by valproic acid and carbamazepine are also at greater risk for NTDs. 