The most common first symptom of pregnancy is a missed period. Other common symptoms of pregnancy in the first trimester include:  Nausea or vomiting, also known as morning sickness. Tender, swollen breasts. Increased urination. Fatigue, or extreme tiredness. Food aversions or cravings. Dizziness. Heartburn and constipation.   Slight bleeding or cramping. Mood swings.