You wake at 2am like you've climbed out of a sauna. Sheets damp, pyjamas stuck to you, doona thrown off. Ten minutes later you're shivering because everything you're wearing is wet.
Night sweats get talked about with menopause and with the first weeks after birth, but almost nobody warns you they happen during pregnancy too. They do, and they can turn up in any trimester.
Why your body is doing this
We're not clinicians, so this is the general picture rather than us presenting ourselves as the authority on your endocrine system.
Your internal thermostat is running differently. The part of your brain that regulates body temperature is sensitive to the hormones that rise in pregnancy. Small changes in body heat can trigger a bigger cooling response than they used to, which means flushing and sweating over what would previously have been nothing.
There's a lot more blood to move. Blood volume increases substantially during pregnancy, vessels near the skin dilate to cope, and heat radiates outward. It's why your skin can feel hot to the touch when the room isn't.
You're generating more heat around the clock. Your metabolic rate is higher than usual, and that doesn't pause overnight.
Your temperature dips in the early hours anyway. That's a normal part of sleep. In pregnancy the response to it can overshoot, which is why 2am to 4am is the classic window for a flush followed by a sweat followed by chills.
Raising Children Network covers the broader picture of how sleep changes across the trimesters, if you want the wider context.
Normal, versus worth a call
Usually unremarkable:
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Waking damp or hot with no fever on a thermometer
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Sweating that comes in waves and settles once you've cooled down
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Feeling otherwise well
Worth ringing your midwife or GP:
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A temperature of 38°C or above. Take your temperature rather than guessing.
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Sweats with shaking chills or teeth chattering
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A burning feeling when you wee, a cough, or an unexplained rash
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Sudden weight loss, or a racing or pounding heart
The distinction that matters is fever versus flush. Hormonal sweating doesn't come with a raised temperature. Infection can, and infections in pregnancy want treating promptly rather than waiting out. A cheap thermometer on the bedside table settles the question in twenty seconds.
Five things that make the nights easier
Natural fibres, and nothing synthetic
Polyester holds heat and moisture against your skin, which is the whole problem. Cotton, bamboo and other natural fibres let air move and pull moisture away.
This is the one thing in your control that makes the most difference, and it's why our 3-Piece Maternity Pyjamas are cut from breathable fabric with a soft waistband. The three pieces matter here more than you'd expect: you can shed a layer at 2am without getting fully undressed in the dark.
The towel trick
Sleep on a folded cotton bath towel. If you wake up drenched, pull the towel out and you're back on dry sheets in five seconds instead of changing the whole bed at 3am.
Nobody tells you this one and it's the tip most women come back to us about.
Layers you can remove without getting up
A sheet plus a light blanket beats one heavy doona every time. Half the misery of a night sweat is the getting-up-and-sorting-it-out, not the sweat.
Cold water within reach
An insulated bottle on the bedside table. A few mouthfuls of cold water when you wake flushed helps, and it saves a trip to the kitchen.
Deal with the room before you get in
Cool it down earlier in the evening rather than reacting at 2am. A fan on low, a window open, curtains closed against the afternoon sun in summer.
If you're in the thick of an Australian summer, we've written specifically about sleeping through a heatwave while pregnant, and about setting up a bedroom that works with you.
Worth mentioning at your appointment
Night sweats aren't usually a red flag, but they're worth a sentence at your next check-up anyway, particularly if they're broken sleep three or four nights a week. Sleep debt in late pregnancy is worth taking seriously on its own terms.
Beth is an Australian midwife who talks about the physical realities of pregnancy without dressing them up, which some women find easier reading than a clinical fact sheet.
The short version
Hormones, more blood, a faster metabolism and an overactive internal thermostat. Wear natural fibres, sleep on a towel, keep layers you can throw off, and keep a thermometer nearby so you can tell a flush from a fever.
Frequently Asked Questions
Will this keep happening after the birth?
Postpartum night sweats are very common, especially in the first couple of weeks, as your body sheds the extra fluid it's been carrying. They usually settle on their own. The towel trick works just as well then, and you'll have more use for it.
Can night sweats hurt my baby?
Ordinary hormonal sweating won't. An actual fever of 38°C or above is different and does need checking, which is the reason for the thermometer.
Am I dehydrated?
You can be, if you're sweating heavily night after night and not replacing it. Drink through the day rather than loading up right before bed, since that just swaps one reason for waking with another.
Is it worse in a particular trimester?
It varies. Some women get it early alongside the other first trimester symptoms, others only in the third when their metabolic rate is highest. Both are normal, and so is not getting it at all.
The information in this article is general in nature and intended as comfort support only. It is not medical advice. Always consult your midwife, GP, or a qualified healthcare provider for guidance specific to your situation.
