While the only fully reliable method of pregnancy detection is a blood test from a doctor, Mayo Clinic explains that early symptoms, such as nausea, increased urination, fatigue and strange food cravings, hint at a pregnancy while it's still too early for a test. These symptoms may vary from one woman to another but are generally present in the early stages of pregnancy.
WebMD explains that the first sign many women have that they are pregnant is fatigue. They may even find out about their pregnancy when seeking treatment for sudden, unexplainable fatigue. While food cravings are a well-known sign of pregnancy, food aversions are just as likely to occur in the early stages of pregnancy when the stomach is most sensitive.
Mayo Clinic notes that the hormones of early pregnancy may cause the breasts to swell and become extremely tender in some women, while others experience a heavy or full sensation. Slight bleeding before or after a missed period is also a common sign of early pregnancy, but Mayo Clinic explains that this harmless phenomenon is known as implantation bleeding and simply means a zygote has implanted itself in the uterine lining. Other women experience cramping with the absence of a menstruation due to the uterine changes underway to accommodate the fetus.