You were warned about the swelling, the back pain, the getting-up-to-wee. Nobody mentioned that being pregnant in an Australian summer feels like running a permanent low-grade fever while also being told not to take anything for it. If you're due anywhere near December through February, this is worth reading before the third trimester makes everything harder to fix.
Why pregnancy runs hot even before the weather does
Pregnancy increases blood volume by up to around 50% and raises your basal metabolic rate — your body is doing more work and moving more blood, both of which generate more heat as a byproduct. Progesterone also raises core body temperature slightly on its own. None of this is a malfunction; it's your body running a bigger operation. But it means the baseline you're working from is already warmer than pre-pregnancy, before an actual heatwave adds anything on top.
What actually helps, trimester by trimester
Hydration does more work than people expect — dehydration reduces your body's ability to sweat effectively, which paradoxically makes you feel hotter and more uncomfortable, not less.
Elevate your feet and avoid tight waistbands in the evening — swelling and heat compound each other, and anything constricting circulation makes both worse.
Sleep on your left side with a pillow between your knees from the second trimester on, both for circulation and because it's easier to stay in one comfortable position when you're not also fighting your pyjamas.
Why fabric matters more in pregnancy than usual
A bump changes how fabric sits against skin — waistbands that used to be loose become tight, and skin-on-fabric contact increases across a larger surface area, especially where the bump touches the mattress or a partner overnight. TENCEL™ Modal's moisture-wicking matters more here simply because there's more skin generating more heat for longer stretches of the night. The Short PJ Set's relaxed cut is worth checking against your current size rather than your pre-pregnancy one — sizing up, not just switching fabric, is often the actual fix. Our night sweats sleepwear guide covers the same fabric logic, even though the hormones driving it are different.
The honest bit
No pyjama set fixes pregnancy insomnia, restless legs, or the genuine physical discomfort of a summer third trimester — those are pregnancy doing what pregnancy does, and there's a real limit to what clothing changes. If you're also experiencing swelling in your face or hands, sudden severe swelling, headaches or vision changes alongside the heat, that combination needs a call to your midwife or GP promptly rather than a fan and a wait-and-see.
The short version
Pregnancy runs hot before summer even arrives, so treat the two as additive rather than solving one and hoping it covers both. Our piece on postpartum night sweats picks up the story for the other side of the birth, and how to sleep in a heatwave covers the room side of the equation.
General information, not medical advice. Anything that worries you in pregnancy belongs in front of your GP or midwife — that's what they're for.
