While symptoms among women vary, BabyCenter indicates that a common symptom of pregnancy is nausea or vomiting. Other early symptoms include breast tenderness, fatigue, frequent urination, heightened sense of smell and food aversions.
Occasionally, women may notice spotting or bleeding when their period is expected. BabyCenter points out that while spotting is normal, if the bleeding is accompanied by pain, the woman should contact her doctor immediately, as this is a possible sign of an ectopic pregnancy.
Even if multiple symptoms are present, BabyCenter cautions against taking a pregnancy test at three weeks, because it is likely too early for the test to register an accurate result. Instead, wait until a week after missing a period to take a pregnancy test.