The form of vitamin A in Pregnacare is carotene, the animal form, which is only absorbed by the body in the amounts you need. It is impossible for carotenes to be toxic. The type of vitamin A you are warned against in pregnancy is retinol - the animal form (hence the warnings about pate). There is no retinol in Pregnacare, therefore it is perfectly safe. And of course, as others have said, it would not be sold for use in pregnancy if it wasn't.
You could just take folic acid but research does show that folic acid is more effective taken in conjunction with other B vitamins such as those in Pregnacare.
I took it through both my pregnancies and now while I'm breastfeeding.