Yes, you may take it through out pregnancy and nursing. The body uses the drink just like any other food.
Are you asking about the food supplements that Moreless suggest like lecithin, kelp and other concentrated food sources....or are you asking about your own choice of supplementation?
Since things like granulated lecithin and kelp are food source supplements, you can take them along with food or the drink.
Other types of supplementation may or may not help with pH balance. It's best to stick to the pH balance plan until you understand how pH really works with your body. :)