In early pregnancy, a slight tingling sensation in the stomach is normal. In early pregnancy, the hormonal effects of estrogen and progesterone increase, causing the ligaments of the uterus to loosen. During this period, the gestational sac will increase in size and the uterus will also increase in size. During the process of enlargement, a slight tingling sensation will occur. Irregular vaginal bleeding is a sign of abnormality and should be treated promptly by finding the cause. In early pregnancy, there is a risk of preterm miscarriage or ectopic pregnancy, which may be accompanied by vaginal bleeding and stomach pain.