1. Early symptoms of one month pregnancy One month pregnancy refers to about 4 weeks that have passed since the last menstrual period. At this time, many women may not realize they are pregnant. However, some early symptoms are already starting to appear. 1. Breast swelling and pain About one month into pregnancy, women’s breasts will feel swelling and pain. This is caused by changes in hormone levels that lead to breast tissue hyperplasia. The nipples and areolas also become more sensitive at this time. 2. Nausea and vomiting. During one month of pregnancy, many women will experience nausea and vomiting due to changes in hormonal levels in the body.