1)  Pregnancy and Nutrition

When you’re pregnant, nutrition is more important than ever. You need more of many important nutrients than you did before pregnancy. Making healthy food choices every day will help you give your baby what he or she needs to develop. It will also help make sure that you and your baby gain the proper amount of weight.

https://medlineplus.gov/pregnancyandnutrition.html

2) The importance of maternal nutrition during breastfeeding: Do breastfeeding mothers need nutritional supplements?

Breastmilk is the best food for newborns and infants. The nutritional stores of a lactating woman may be more or less depleted as a result of the pregnancy and the loss of blood during childbirth. Lactation raises nutrient needs, mainly because of the loss of nutrients, first through colostrum and then through breastmilk.

https://www.sciencedirect.com/science/article/abs/pii/S2341287916300643