vitamins

So I have been taking my prenatal vitamins everyday for 4 months now. I was told that I need to start taking calcium vitamins because my body doesn't have enough calcium and my prenatal don't have calcium in them either. So I have two types of calcium vitamins one is called Calcium 600 which has 400 IU of Vitamin D , and 7.5mg of zinc. The other vitamins I have is called Caltrate which has 800IU of vitamin D but has 7g of sugar and 20 mg of sodium. I'm not sure which one I should take. Or is there a type of calcium vitamin for pregnancy? If so what is it called and where can I find it at?  Please and thank you for your time