Many individuals report feeling warmer or experiencing flu-like symptoms around their menstrual period. While a sensation of increased body temperature is common, a true fever is less typical and warrants closer attention. Understanding the distinction between normal cyclical temperature shifts and a genuine fever is important for managing one’s health.
Normal Temperature Shifts
The human body’s temperature naturally fluctuates throughout the day and in response to hormonal changes during the menstrual cycle. During the first half, known as the follicular phase, body temperature tends to be lower. After ovulation, typically around the middle of the cycle, there is a distinct temperature increase. This rise is primarily due to progesterone, which becomes dominant in the luteal phase, the second half of the cycle.
Progesterone acts on the hypothalamus, the brain’s temperature-regulating center, to elevate basal body temperature (BBT). This elevation is slight, ranging from 0.5 to 1 degree Fahrenheit (0.2 to 0.5 degrees Celsius) above the pre-ovulation temperature. This minor increase is a normal physiological response and is not considered a true fever. The temperature remains elevated until progesterone levels drop, signaling the start of menstruation, returning to the lower follicular phase range. Some individuals might experience symptoms like body aches, fatigue, or mild nausea, sometimes called “period flu,” caused by prostaglandins, chemicals that also help the uterus contract. Prostaglandins can occasionally cause a mild temperature increase.
Underlying Medical Causes
While a slight temperature rise is normal during the menstrual cycle, a true fever (100.4°F or 38°C or higher) during or around your period can indicate an underlying medical condition. Several conditions may present with fever that coincides with menstruation.
Pelvic Inflammatory Disease (PID) is an infection of the female reproductive organs, including the uterus, fallopian tubes, and ovaries. PID can cause symptoms such as lower abdominal and pelvic pain, unusual or foul-smelling vaginal discharge, and sometimes fever with chills. This bacterial infection can spread from the vagina or cervix to the upper reproductive system.
Toxic Shock Syndrome (TSS) is a rare but serious bacterial infection linked to tampon use, especially super-absorbent types, if left in too long. Symptoms of TSS develop suddenly and include a high fever (above 102°F or 38.9°C), low blood pressure, a sunburn-like rash, vomiting, diarrhea, and muscle aches. TSS requires immediate medical attention due to its rapid progression and potential for severe complications.
Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, can cause significant inflammation. While not a direct cause of fever, severe inflammatory flares from endometriosis can lead to a low-grade fever.
Urinary Tract Infections (UTIs) are common infections that can affect the bladder, kidneys, or ureters. UTIs can cause symptoms like frequent urination, painful urination, and pelvic discomfort. If a UTI spreads to the kidneys, it can cause a fever, along with back pain and other flu-like symptoms. Menstruation can increase susceptibility to UTIs due to hormonal changes and hygiene practices.
When to Seek Professional Medical Advice
It is important to recognize when a fever during your period warrants medical attention. A temperature consistently at or above 100.4°F (38°C) should prompt a call to a healthcare provider. This is particularly true if the fever persists for more than a day or two or is accompanied by other concerning symptoms.
Seek immediate medical care if a fever during your period is accompanied by severe abdominal pain, unusual or foul-smelling vaginal discharge, or a sudden rash. Other red flags include dizziness, confusion, persistent vomiting, a stiff neck, or difficulty breathing. Recurrent fevers with each menstrual cycle should also be discussed with a doctor to investigate potential underlying causes. Early diagnosis and treatment are important for managing underlying conditions.