Is a body temperature of 37°C two days before menstruation a sign of pregnancy?

　　A body temperature of 37°C two days before menstruation may indicate pregnancy, as increased metabolism and progesterone production can cause a rise in basal body temperature. However, it might not be pregnancy either, since body temperature alone is not the sole criterion for determining pregnancy. Other conditions such as colds, acute suppurative tonsillitis, chronic simple pharyngitis, urethritis, or mumps could also cause elevated body temperature.

　　I. Yes — It Could Be Pregnancy

　　If a woman becomes pregnant, her ovaries secrete higher levels of luteinizing hormone, leading to increased progesterone levels in the body, which raises basal body temperature. This condition typically lasts about 14 days. Pregnancy causes estrogen and progesterone levels to rise, accelerating metabolism to meet the needs of embryo implantation, resulting in a slightly elevated body temperature.

　　II. No — It Might Not Be Pregnancy

　　1. Common cold: If respiratory syncytial virus, adenovirus, or other pathogens infect the body before menstruation, causing a cold, excessive inflammatory mediators in the body may affect the function of the thermoregulatory center, leading to fever. Other symptoms may include headache and cough.

　　2. Acute suppurative tonsillitis: When the tonsils are infected by pathogens and develop acute suppurative inflammation, this condition often triggers an immune system stress response, resulting in elevated body temperature. It may also be accompanied by throat swelling and sore throat.

　　3. Chronic simple pharyngitis: Excessive smoking or drinking before menstruation, or the spread of inflammation from nearby uterine organs, may lead to chronic simple pharyngitis. This increases inflammatory mediators in the body, enhancing the function of the thermoregulatory center and causing symptoms such as low-grade fever and a sensation of a foreign body in the throat.

　　4. Urethritis: Before menstruation, urinary tract injury or obstruction may lead to infection of the urethral mucosa, causing inflammatory changes. The resulting immune response can trigger symptoms such as fever, urgency of urination, and hematuria (blood in urine).

　　5. Mumps: Hormonal fluctuations before menstruation can weaken immunity, increasing susceptibility to various pathogens. If mumps virus infection occurs, leading to mumps, it can cause the release of inflammatory mediators, overstimulating the thermoregulatory center and resulting in fever, fatigue, and other symptoms.

　　Body temperature alone cannot confirm pregnancy. Menstrual patterns should be observed—delayed menstruation along with elevated temperature may strongly suggest pregnancy. A pregnancy test strip or blood hCG test can help confirm whether pregnancy has occurred.