Level 1: Physical Changes 1. Breast Swelling and Pain In early pregnancy, due to changes in hormonal levels, breasts will become more sensitive and swollen and painful. This is because hormones cause the breasts to grow in size and prepare them for milk production. 2. Nausea and Vomiting During early pregnancy, many women will experience nausea and vomiting. This is due to changes in hormonal levels in the body that cause digestive problems. This condition usually occurs within the first three months of pregnancy. 3. Fatigue In the early stages of pregnancy, many women will feel very tired.