Hi, Welcome to HCM. Pregnancy is a physically demanding state. You need the nutrients not only to maintain your health but also to support the growth of the feotus in utero. Hence body requirement of nutrients also increases. In pregnancy dietary supplementation alone is not sufficient to meet these nutritional needs. There the pharmacological supplements come in to picture. Centrum Materna is a multi vitamin preparation which contains all the required minerals and vitamins during pregnancy. Folic acid and Vitamin B12 are the most essential vitamins required that promotes the growth of foetus especially these have protective effect on Nervous system of the baby. Similarly Zinc and DHA are also required for the growth. Likewise all the other vitamins and minerals are also essential. Coming to calcium carbonate is essential as pregnancy is a state of negative calcium metabolism leading to decreased calcium in bones. Calcium is required for the bone growth of the child. Coming to Iron preparations - According to WHO ( World Health Organisation) all the pregnant women require the iron supplementation in the form of tablets especially during the last 100 days of pregnancy. Though iron is present in green leafy vegetables, jaggery, etc., the bio availability of iron is less and thus cannot completely provide the required amount of iron for the mother and baby. Hence iron supplementaion in the form of tablets is essential. Hope your doubts are cleared. You can take all these medicines without any doubt for the safety and better future of yourself and your baby. Let me make it clear to you that all these medicines you are adviced to take are only supplements and not substitutes for your diet. So, take good diet ( 2 eggs daily, fish atleast twice a week, meat once or twice a week, lots and lots of green leafy vegetables, fresh vegetables and fruits). Wish you a happy pregnancy. All the best and take care