Folic acid is good to prevent birth defects. And ferrous for iron n to avoid anemia n multivit just in case u lose some nutrients from nausea with vomitting
My doc recommends a prenatal vitamin for everyone and omega 3 if u have less than 3 servings of fish each week.
Personally I take a folate/vit b complex. I chew golden roasted flaxseed for my omega 3 and fiber. (it has to be chewed to be useful). I eat a banana, apple and an orange a day. I track these on my fitness pal and usually I get all the vitamins I need.
I drink almond milk for my calcium. Vitamins esp (ADEC) as well as calcium are better absorbed in a food state. Calcium citrate is more bioavailable then calcium bicarbonate. Checking the bioavailability for each vitamin supplement takes too much work for me so I just eat the foods directly.
That combo if fine. Omega 3 is not really a vitamin it's a fatty acid. Great for building cell membranes etc.
I am taking prenatal multi+ extra vitamin C.