Chills or hot flashes during your period? Here's why

In short: Chills or hot flashes during your period are common and are usually caused by normal changes in your body: the drop in estrogen and progesterone just before bleeding starts, and chemicals called prostaglandins that help your uterus contract. Low iron from heavy periods, poor sleep and stress can make you feel colder or hotter too. If you have a fever of 38 °C or more, or chills with pelvic pain or foul-smelling discharge, it may be an infection, and you should see a doctor the same day.

Ever found yourself shivering under a blanket one moment and tossing it off the next, all while you're on your period? You are not alone.

Many women notice chills or hot flashes around their period, and while it might seem unusual, it's more common than you would think. Your body is working hard during your period, and those temperature swings are a real part of the process.

What's happening in your body during your period?

Your period is not just about bleeding; it is a full-body hormonal rollercoaster.

Each month, your body cycles through rising and falling levels of estrogen and progesterone. These hormones do not just affect your uterus; they also affect your brain, mood, energy levels, and yes, even your internal thermostat.

Here is a detail many people get the wrong way round. Your body temperature rises slightly after ovulation, in the second half of your cycle, because progesterone nudges your thermostat up a little. When your period starts, progesterone falls and your temperature drops back to its usual level. So your temperature does not rise during your period; it settles down. That shift, from slightly warm to back to baseline, is one reason some women feel chilly or unsettled in the first days of bleeding.

Why do chills or hot flashes happen?

1. Hormonal fluctuations

Estrogen and progesterone both play a part in how your body controls its temperature. Right before your period, both fall. For some women, this drop can trigger brief hot flashes, sweating at night, or chills.

Think of it like this: your body is adjusting to a hormonal shift, and the thermostat gets confused for a bit.

2. Prostaglandins at work

Your body releases prostaglandins, natural chemicals that help the uterus contract and shed its lining. They are also behind period cramps. Prostaglandins can affect the hypothalamus, the part of your brain that controls temperature, and they can cause other whole-body effects such as nausea, loose stools and headaches. Together, this can leave you feeling feverish or shivery, especially on the first day or two when cramps are strongest.

3. Low iron levels

If you have heavy periods, you might lose enough blood to feel tired, dizzy, or cold. This could be a sign of low iron levels (anaemia), which commonly causes chills, weakness, cold hands and feet, and sensitivity to temperature. Your iron stores can run low even before your blood count shows it; read more about what ferritin tells you about your iron stores.

4. Poor sleep

Many women sleep badly around their period, because of cramps, bloating or night-time pad changes. Your temperature control is closely tied to sleep, so when you are short of it, you can feel colder than usual during the day, or wake up hot and sweaty at night.

5. Stress and increased sensitivity

When you are anxious or under pressure, stress hormones can bring cold, clammy hands one minute and a hot, flushed face the next. If you are already feeling tired, bloated, or emotionally drained, your body may be more sensitive to temperature changes. What feels like a normal room to others might feel like an icebox or a sauna to you.

6. An infection, if you have a fever

Period hormones can make you feel hot or cold, but they do not usually cause a real fever. If a thermometer shows a temperature of 38 °C or more, think about other causes. A pelvic infection, a urine infection, or a cold or flu can coincide with your period. Chills together with pelvic pain, burning when you pass urine, or unusual, foul-smelling discharge should be checked by a doctor.

It's easy to dismiss these symptoms; after all, they're not always talked about in the usual "period 101" chats. But if you've felt your teeth chatter or your skin sweat for no obvious reason during your period, you're having a very real physical response.

Could it be perimenopause?

Hot flashes are best known as a sign of the years around menopause. Perimenopause, the time when your cycle starts to change before periods stop, usually begins in your 40s, and sometimes in your late 30s. If you are in that age group and your hot flashes are new, come with changes in your cycle, or happen at times other than your period, it may be worth reading about how menstrual changes can signal perimenopause. For most women in their 20s and 30s, temperature swings around the period are linked to the normal monthly cycle instead.

If you are past that stage and want to know more about hot flashes in menopause, that is a different pattern with its own causes.

Temperature changes after giving birth

Your body temperature can also go up and down in the weeks after delivery, as hormones shift sharply. If you are a new mother, you may find these articles on feeling cold after giving birth, even when it is warm outside and on night sweats after birth helpful.

What helps

Here are some simple ways to stay comfortable during those temperature swings:

Layer up: Wear breathable cotton layers so you can add or remove clothing quickly when chills or hot flashes hit. Keep a light shawl or dupatta handy.

Use warmth: A hot water bag or heating pad on your lower belly or back can ease cramps and chills at the same time. A warm bath or shower can help too.

Eat warm, regular meals: Skipping meals can leave you feeling colder and shakier. Warm, simple foods like dal, khichdi, soups and haldi doodh are comforting and easy on the stomach.

Stay hydrated: Water, coconut water, buttermilk and warm herbal drinks help your body regulate its temperature and can ease bloating, too.

Eat iron-rich foods: Think spinach and other greens, lentils, chana, rajma, jaggery, sesame seeds, eggs, fish or meat, especially if your periods are heavy. Have them with a source of vitamin C, like amla, lemon or guava, to help your body absorb the iron.

Protect your sleep: Keep your room comfortably cool, use a lighter blanket you can add to, and try to go to bed at a regular time. A period-proof pad or period underwear at night can mean fewer wake-ups.

Move gently: A short walk, stretching or gentle yoga can improve blood flow, ease cramps and lift your mood. There is no need to push hard on heavy days.

Track your cycle: Use a period app or a journal to spot patterns. Knowing when symptoms usually start can help you prepare.

When to see a doctor

Talk to your gynaecologist if chills or hot flashes happen every month and disturb your daily life, if they are new and you are in your late 30s or 40s, or if your periods are heavy and you often feel tired.

Seek care the same day if you have:

• A fever of 38 °C or more
• Chills together with foul-smelling discharge or pelvic pain

Go to hospital straight away if you are soaking a pad every hour, or you feel faint or collapse.

Feeling like your body is turning hot and cold during your period is not just weird; it is a sign of how complex and powerful your hormonal system is. Most of the time, a little warmth, food, rest and patience is enough to see you through.

Want a doctor's view? Talk to a gynaecologist on Femease.

Questions women ask

Is it normal to feel cold during your period?

Yes. Your temperature falls back to its usual level as progesterone drops, and prostaglandins, poor sleep or low iron can add to the chill. Check with a doctor if it is severe or comes with a fever.

Why do I get hot flashes before my period?

Estrogen and progesterone both fall in the days before your period. For some women, this drop briefly confuses the brain's temperature control, causing a feeling of heat, flushing or night sweats.

Does your body temperature go up during your period?

No. Your temperature rises slightly after ovulation and stays a little higher until your period starts. When bleeding begins, it falls back to normal. A true fever during your period is not caused by the period itself.

Can low iron make you feel cold?

Yes. Low iron often shows up as cold hands and feet, tiredness and feeling chilly. If your periods are heavy, ask your doctor about a blood test.

Are period chills a sign of infection?

Usually not, but they can be. If you have a temperature of 38 °C or more, or chills with pelvic pain or foul-smelling discharge, see a doctor the same day.