Level 1: How many days into pregnancy will there be any reaction? Reaction within a few days of pregnancy means that a woman’s body will undergo some unusual changes after conception. These changes may include physical discomfort, mood swings, and more. Generally speaking, the first to fourth week after pregnancy is the time when reactions are most likely to occur. Level 2: How many days during pregnancy will nausea and vomiting occur? Early in pregnancy, around 4-6 weeks after conception, many women will experience symptoms of nausea and vomiting. This symptom is often referred to as \”morning sickness\” because they tend to occur after waking up in the morning. Level 3: How many days into pregnancy will breast swelling and pain occur? in early pregnancy