Night sweats in the third trimester: how to sleep better

You go to bed, you fall asleep, and two hours later you wake up with your clothes stuck to your back and a damp pillow. It isn’t a fever and the room isn’t hot: they’re night sweats, one of the most common and least talked about symptoms of the third trimester. Your body has shifted the way it regulates temperature, and it shows up the most at night.

This isn’t something that needs to be “cured.” It’s late-pregnancy physiology and it sorts itself out after birth. But understanding why it happens and tweaking three or four things about your bedroom can be the difference between sleeping straight through and getting up three times to change.

Cool bedroom with a slightly open window, light cotton sheets, and a water bottle on the nightstand — A cool bedroom, cotton clothes, and water within reach are the three things that bring night sweats down the most

ℹ️This is a general guide

What follows are general pointers for a normal pregnancy symptom. It isn’t a substitute for your healthcare provider: if your OB-GYN or midwife told you something different, always follow their advice over this guide. Further down, I cover the signs that are worth bringing up.

Why night sweats show up at the end of pregnancy

It isn’t one thing, it’s several stacking on top of each other:

Your basal metabolic rate goes up by about 20% at the end of pregnancy (figures referenced by the American College of Obstetricians and Gynecologists, ACOG). Your body generates more heat at rest, simply because it’s working harder.
Blood volume rises by 40-50%. More blood circulating means more heat to release, and your skin does that by sweating.
Hormonal changes shift your internal thermostat. Estrogen and progesterone affect the hypothalamus, the part of the brain that regulates temperature, and leave it more “sensitive.”
Your body lowers its temperature at night to sleep, and that shift, layered on top of everything above, translates into sweat. That’s why you notice it more asleep than awake.

On top of that, in the third trimester you move less, struggle to find a comfortable position, and often sleep with more bedding than your body now needs.

What helps the most (ordered by impact)

You don’t need to buy anything expensive. Start with what moves the needle most:

1. Lower the bedroom temperature

This is what works best. A room between 18 and 20 °C (around 64-68 °F) is the range where the body falls asleep most easily. If you have AC or a fan, use it. If you don’t, air the room out well before bed and leave a window cracked open if noise and safety allow.

2. Natural-fiber clothing and sheets

Cotton, linen, and bamboo let your skin breathe and absorb moisture. Synthetic fabrics (polyester, satin) trap heat and leave the sweat sitting on you. This applies to your pajamas and to your sheets.

💡The towel trick

Lay a thin cotton towel over the sheet, across the area where your back rests. It absorbs the sweat without making you remake the whole bed at 3 a.m.: if it gets damp, you pull it off and keep sleeping. Keeping a backup pair of pajamas on the nightstand helps for the same reason.

3. Water within reach and a lukewarm shower before bed

Sweating at night dehydrates you. Keep a bottle on the nightstand and take sips when you wake up. A lukewarm shower (not cold, not hot) before bed lowers your body temperature and gets it ready for sleep.

4. Mind your dinner triggers

Heavily spiced foods, chili, and heavy dinners raise body temperature and make the sweating worse. Eating light and early helps. If you also deal with nighttime heartburn, light dinner recipes for pregnancy covers both at once.

Quick reference: what to adjust based on how it’s hitting you

Situation	What to prioritize
You sweat but still sleep through	Cotton clothes + water within reach. No need for more.
You wake up 1-2 times to change	Drop the room to 18-20 °C + towel over the sheet + backup pajamas.
Summer and a lot of heat	Fan pointed at the wall (not directly at you) + lukewarm shower before bed + thin linen sheet.
Sweating + you can’t fall back asleep	Cold water bottle on the nightstand, lights off or very dim, no phone when you wake up.

How to tell when it’s normal and when to check in

Pregnancy night sweats on their own are normal. What changes the picture is when they show up with other signs. Worth talking to your provider if the sweating comes with:

Fever (38 °C / 100.4 °F or higher), chills, or a general feeling of being unwell.
A racing heartbeat at rest, or the feeling that your heart is “taking off.”
Unexplained weight loss or very intense sweating during the day too.
A bad headache that won’t go away.

This isn’t to scare you: the vast majority of third-trimester night sweats have nothing behind them. But sweating can also accompany other things (an infection, for example), and that’s why it’s worth looking at the full picture, not in isolation.

If it helps to see your own patterns (which nights you sweat more, whether it lines up with what you ate or the heat), memobebe lets you log rest and how you feel in a couple of taps, without turning into another chore. If you want to go deeper into what to track across pregnancy, I cover it in pregnancy journal: what to track and why.

Frequently asked questions

Is it normal to sweat this much at night during pregnancy?

Yes. It’s one of the most common symptoms of the second and third trimesters, thanks to the combination of higher metabolism, more circulating blood, and changes in the internal thermostat. As long as it doesn’t come with fever or other signs, it’s expected and it passes after birth.

How long do night sweats last?

They tend to be most intense in the third trimester and continue for a few weeks postpartum, since hormones take time to settle. For many women they’re actually stronger in the first days after delivery, and then they fade on their own.

Can I use deodorant or antiperspirant while pregnant?

Yes, regular deodorants and antiperspirants are considered safe in pregnancy. If your skin is more sensitive than usual, go for unscented options. What moves the needle most on night sweating isn’t the deodorant, it’s the bedroom temperature and the bedding.

Will drinking less water at night reduce the sweating?

No, and it can backfire. Sweating dehydrates you, so cutting off water just leaves you worse. Hydrate well during the day and keep sips within reach at night. If you’re getting up to the bathroom a lot, load more fluid into the first half of the day and less in the two hours before bed.

Is pointing the fan directly at me a bad idea?

It’s better aimed at a wall or the ceiling so it moves the air around the room without blasting you. Direct air all night can dry out your throat and nose and leave your neck stiff. The goal is to bring the room temperature down, not to freeze one side of your body.

Third-trimester night sweats are uncomfortable but temporary, and they respond very well to simple changes: a cool bedroom, cotton, water within reach, and a light dinner. It isn’t something to grit your teeth through, and it isn’t something to medicalize either. If you want a simple way to keep tabs on which nights you actually rest better, memobebe is built for this.

For what to eat for symptoms across each stage of pregnancy, foods for pregnancy symptoms has the full picture. Find more on pregnancy in our pregnancy section.