A higher temperature during your period often raises an understandable question: is this just another individual response to menstruation, or could it be a sign of inflammation or another medical condition? The situation can be especially difficult to interpret when the thermometer shows a temperature just above 37 °C, while nothing else seems unusual apart from the usual menstrual pain and weakness.
Can Your Temperature Rise During Your Period?
Yes, a woman’s body temperature does not have to remain exactly the same throughout the menstrual cycle. However, the statement that “temperature changes with the cycle” is sometimes taken too literally, as if a temperature of 37.5 or even 38 °C during menstruation can automatically be considered a normal response to having a period. That is not the case.
After ovulation, body temperature usually rises slightly under the influence of progesterone. This is most noticeable when measuring basal body temperature – first thing in the morning, immediately after waking up and before any physical activity. On average, temperature during the luteal phase, or the second half of the cycle, may be approximately 0.3–0.7 °C higher than before ovulation. When progesterone levels fall before menstruation, temperature usually begins to decrease as well.
That is why basal body temperature (the body’s lowest temperature at complete rest, measured immediately after an uninterrupted period of sleep) and the temperature a woman checks during the day because she feels hot, weak, or chilled are not quite the same thing. A basal body temperature chart can be used to observe changes associated with ovulation and different phases of the cycle. A high body temperature accompanied by feeling unwell is a different clinical situation.
There is another complication: normal body temperature varies somewhat from person to person and changes throughout the day. For that reason, I would not draw an artificial line such as “37.2 °C is normal, but 37.3 °C means illness.” A single number without context tells us very little.
What matters much more in practice is the overall situation. A small, short-lived change in temperature around the beginning of menstruation, with otherwise normal well-being, especially if it is familiar and follows a similar pattern from cycle to cycle, does not necessarily indicate illness. A temperature of 38 °C or higher, however, is generally considered a fever. I would not explain that temperature simply by the fact that a period has started.
Why Can Your Temperature Rise Before Your Period?
Sometimes a woman says, “I can tell my period is coming just by my temperature.” There can indeed be a physiological explanation for this.
After ovulation, progesterone production increases. Among its other effects, this hormone influences the body’s thermoregulatory center, so body temperature becomes slightly higher during the second half of the cycle. This is especially noticeable in women who regularly measure their basal body temperature under consistent conditions.
This increase does not begin immediately before a period. It starts after ovulation and continues throughout the luteal phase (the period from ovulation until the first day of the next period). As menstruation approaches, progesterone levels fall, and temperature usually falls as well. Therefore, a small difference between the first and second halves of the cycle is normal physiology, not “inflammation before your period.”
There is an important qualification, however. A physiological change is usually measured in tenths of a degree. If your temperature suddenly rises to 38 °C before your expected period and you develop true chills, body aches, pronounced weakness, or other symptoms of illness, it would be incorrect to explain this by progesterone. The fact that something happens on a particular day of the cycle does not prove that the cycle itself is the cause.
Why Can You Have a Higher Temperature During Your Period?
If an elevated temperature is detected after menstrual bleeding has already started, there can be several explanations. Sometimes it really is a small change in thermoregulation and well-being associated with menstruation. However, pelvic inflammatory disease, a urinary tract infection, a respiratory or gastrointestinal infection, and many other conditions can simply happen to occur at the same time as a period.
Changes in Thermoregulation Related to the Menstrual Cycle
Body temperature is a regulated physiological measurement, not a constant 36.6 °C. It is influenced by the time of day, physical activity, sleep, ambient temperature, and hormonal changes. The menstrual cycle is also part of this picture.
The main physiological rise in temperature is actually associated not with menstruation itself, but with the preceding luteal phase and the effects of progesterone. By the time menstrual bleeding begins, temperature usually starts returning toward the level seen during the first half of the cycle. This transition does not happen at exactly the same moment in every woman, so a slight elevation may persist around the beginning of a period.
This is where it is easy to draw the wrong conclusion. If a woman measures 37.0–37.2 °C on the first day of her period and otherwise feels as she normally does, that number alone does not indicate inflammation. But the opposite conclusion – “I’m on my period, so the temperature must be normal” – is also incorrect. The pattern over time and accompanying symptoms need to be considered.
Higher Temperature With Painful Periods and Other Menstrual Symptoms
For some women, the beginning of menstruation involves more than lower abdominal pain. Weakness, nausea, headache, diarrhea, sweating, a sensation of feeling hot, or, conversely, a chilled feeling may occur at the same time. This response can be particularly noticeable during the first 24 hours, when menstrual cramps are often strongest.
Prostaglandins are involved in this process. These biologically active substances are produced in the endometrium and increase uterine contractions. They play a major role in primary dysmenorrhea, meaning painful periods without an underlying pelvic disease. Prostaglandins do not affect only the uterus, so the symptoms can be quite varied.
But I would not take the next, overly convenient step and assume that painful periods plus a higher temperature mean everything can be explained by prostaglandins. That explanation is not sufficient for a significant fever.
This is particularly important when the pattern of menstruation has changed. For example, a woman may previously have tolerated her periods relatively well but then develop progressively stronger pelvic pain together with an elevated temperature. New or worsening symptoms need to be evaluated separately, even if they occur strictly during menstrual days.
When a Fever May Be a Sign of Pelvic Inflammatory Disease
A fever combined with lower abdominal pain raises the possibility of pelvic inflammatory disease (PID) – an infectious inflammatory process that can affect the uterus, fallopian tubes, and other structures within the pelvis.
With PID, fever is not necessarily the only symptom, or even a symptom that is always present. There may also be unusual vaginal discharge, an unpleasant odor, lower abdominal pain, pain during sexual intercourse, bleeding between periods, or other changes. Some cases can have fairly subtle symptoms.
However, the combination of fever and pelvic pain should not automatically be attributed to menstruation. Clinical guidelines consider a temperature above 38.3 °C one of the additional findings that can support a diagnosis of PID when the overall clinical picture is consistent with it. This does not mean that a woman can diagnose herself with PID simply because her temperature is 38.4 °C. Temperature alone cannot determine the cause. But it is a good example of why a true fever accompanied by pelvic pain should not simply be blamed on menstruation.
It is also concerning when pain becomes noticeably more severe than usual, the temperature continues to rise, or chills, pronounced weakness, or unusual vaginal discharge appear. In this situation, identifying the cause promptly is more important than waiting to see whether everything goes away when the period ends.
When the Cause of a Fever May Have Nothing to Do With Your Period
Sometimes the explanation is much simpler: a woman happens to get sick on the same days her period starts.
A respiratory viral infection, influenza, COVID-19, a gastrointestinal infection, food poisoning, a urinary tract infection, and other illnesses do not follow the menstrual calendar. A fever can therefore happen to appear on the first or second day of a period.
The overall pattern usually provides clues. A runny nose, cough, sore throat, body aches, significant diarrhea or vomiting, pain or burning with urination, or frequent urination suggest that the corresponding causes should be considered rather than looking for a gynecologic explanation for every symptom.
Duration matters as well. If menstruation ends but the fever persists, a direct connection with the period becomes less convincing. The same applies to a temperature that rises on different days of the cycle without a clear, recurring pattern.
What to Do if Your Temperature Rises During Your Period
The first instinct is understandably to decide whether the temperature needs to be brought down. But what to do next depends on more than the number on the thermometer. It is important to consider how different the temperature is from your usual level, how you feel, and what other symptoms appeared at the same time.
Should You Lower a Fever During Your Period?
A slight increase in temperature when you otherwise feel well does not require taking medication just to make the thermometer read 36.6 °C again. Treating a number alone is generally not a useful strategy.
Ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs) used for painful periods are a separate issue. They are commonly used for dysmenorrhea because they reduce prostaglandin production and can therefore relieve menstrual pain. If a woman takes one of these medications for cramps, she is treating dysmenorrhea, not simply trying to “bring down a period-related temperature.”
I would not give universal doses of either ibuprofen or acetaminophen here. The appropriate medication depends on a person’s health, other medications, gastrointestinal conditions, liver or kidney disease, allergic reactions, and other factors. NSAIDs also have contraindications, even though many are available over the counter.
With a true fever, a fever-reducing medication may lower the temperature and improve how you feel, but it does not explain the cause. If severe pelvic pain, unusual discharge, repeated vomiting, or another significant change in your condition occurs at the same time, the fact that your temperature goes down after taking a pill does not make the situation safe. The symptom may improve while the underlying cause remains.
What You Can Do Right Away if Your Temperature Is Elevated
If an unexpected reading seems questionable, it makes sense to check your temperature again under calm, consistent conditions. Do not measure it immediately after physical activity, a hot shower, spending time under a very warm blanket, or drinking a hot beverage. It is better to use the same properly functioning thermometer and the same measurement method, otherwise the results are harder to compare.
Next, I would look at the trend. A single reading of 37.2 °C and a temperature that rises from 37.2 to 38.2 °C over several hours are very different situations.
With a slight increase and otherwise normal well-being, you can rest, drink enough fluids, avoid overheating, and check your temperature again later. There is no need to measure it every five minutes. It is much more useful to determine whether it is going down, remaining approximately the same, or continuing to rise.
At the same time, consider other symptoms. How different is the menstrual pain from what you normally experience? Is there any unusual vaginal discharge or unpleasant odor? Have you developed pain with urination, a cough, sore throat, vomiting, or significant diarrhea? A brief self-check like this often provides more useful information than taking your temperature for the tenth time in a row.
When Repeated Temperature Increases Should Be Discussed With a Doctor
If a slight increase in temperature occurs during almost every cycle, it is useful to first determine whether there really is a consistent pattern. This does not require complicated tracking.
For 2–3 menstrual cycles, you can record the day of your cycle, your temperature, the time and method of measurement, the day your period begins, and when your temperature returns to its usual range. If severe pain, chills, unusual discharge, or other symptoms occur at the same time, note those as well.
These records can help distinguish several very different patterns. In one woman, temperature may be slightly higher during the second half of the cycle and decrease around the beginning of menstruation – a pattern that fits well with the physiological effects of progesterone. Another woman may have a temperature just above 37 °C only during the first few hours of a painful period, after which it quickly returns to normal. In a third woman, the temperature may rise progressively higher with the start of each period while pelvic pain becomes increasingly severe.
That last pattern should not be accepted for years as “just the way my body works,” especially if it was not present before. New symptoms, gradual worsening, or a change in the usual pattern of menstruation are sufficient reasons to discuss the situation with a gynecologist and determine whether there really is a connection with the menstrual cycle and whether further evaluation is needed.
When a Fever Requires More Prompt Medical Attention
A practical reference point for an adult is that 38 °C or higher is considered a high temperature, or fever. But urgency is not determined by the number alone. Sometimes the combination of symptoms matters more than the thermometer reading itself.
Do not wait for your period to end if the fever is accompanied by severe or rapidly worsening lower abdominal pain, significant chills, repeated vomiting, inability to drink normally, fainting or feeling as though you may faint, or a sudden significant deterioration in how you feel. The combination of fever with unusual vaginal discharge and significant pelvic pain also warrants more prompt medical evaluation.
A possible pregnancy is a separate situation. Not every episode of vaginal bleeding is menstruation. If pregnancy is theoretically possible, the bleeding is different from your usual period, and you also develop severe lower abdominal pain, especially on one side, pronounced dizziness, weakness, or fainting, you should not rely solely on the assumption that “my period has started.”
One more simple reference point: if your temperature continues to rise, remains elevated after menstruation ends, or is accompanied by symptoms that do not fit your usual period at all, the cause needs to be investigated separately.
Body temperature does change throughout the menstrual cycle, and small fluctuations do not by themselves indicate illness. The physiological increase of about 0.3–0.7 °C is especially noticeable after ovulation, when progesterone levels rise. But a true fever should not automatically be considered just another symptom of menstruation. A temperature of 38 °C or higher, particularly when accompanied by severe or unusual pelvic pain, chills, abnormal vaginal discharge, vomiting, or a significant deterioration in how you feel, requires looking for the cause. And if a slight temperature increase recurs month after month, it is more useful to track it for 2–3 cycles and identify the actual pattern than to simply try to bring down the number on the thermometer each time.
Clinical Guidelines and Sources
- Baker F.C. et al. Temperature Regulation in Women: Effects of the Menstrual Cycle. A review of changes in body temperature throughout the menstrual cycle, the effects of progesterone, and the physiological rise in temperature during the luteal phase.
- ACOG. Dysmenorrhea: Painful Periods. Recommendations on the evaluation of painful periods, the role of prostaglandins, and the use of nonsteroidal anti-inflammatory drugs for dysmenorrhea.
- CDC. Pelvic Inflammatory Disease (PID) – STI Treatment Guidelines. Clinical guidance on the diagnosis of pelvic inflammatory disease, including the combination of pelvic pain, fever, and other signs of an inflammatory process.
- CDC. Pelvic Inflammatory Disease (PID). Information on symptoms of pelvic inflammatory disease, including lower abdominal pain, fever, and abnormal vaginal discharge.