How to Stay Cool While Sleeping Pregnant (Summer Tips)

If you are pregnant in summer, the maternity forums are full of phrases like "human furnace" and "I literally cannot sleep it's so hot." This is not exaggeration. Pregnancy increases your metabolic rate and blood circulation significantly — you are growing an entire human, and that requires considerable energy that generates heat. Add a 90°F August night and a pregnancy pillow wrapped around your body, and it becomes a genuine physiological challenge to sleep. The good news is that temperature is one of the few pregnancy sleep disruptors that responds reliably to environmental interventions. You can take very practical, concrete steps that make a measurable difference. This guide covers all of them, from the thermostat to the sheets to the shower timing. Pair it with our best cooling sleep products guide for specific product recommendations, and see our third trimester sleep tips for the broader context.

Why Pregnant Women Overheat at Night

Three main mechanisms drive elevated body temperature during pregnancy. First, your basal metabolic rate increases by 15 to 20% to support fetal development and the increased work of the cardiovascular, respiratory, and renal systems. More metabolism means more heat generation. Second, your blood volume increases by up to 50%, and your heart pumps this blood at a higher rate to supply the placenta. Increased blood flow to the skin causes vasodilation — the same effect that makes your cheeks flush in a warm room — which makes the skin feel warmer and means your body is actively radiating heat outward. Third, progesterone, the dominant hormone of pregnancy, causes a slight elevation of basal body temperature similar to the thermal shift after ovulation in the luteal phase of the menstrual cycle. All three factors compound in summer, when the ambient environment provides less of the cooling that normal heat dissipation depends on.

Start With the Room Temperature

Core body temperature naturally drops by 1 to 2°F at sleep onset as part of the circadian sleep initiation sequence. This drop is facilitated by heat dissipation from the skin — which requires the ambient environment to be cooler than your skin. In a 78°F bedroom, there is insufficient thermal gradient for this to happen efficiently. The science-backed optimal sleep temperature is 65 to 68°F for most adults; pregnant women typically report feeling most comfortable sleeping at 64 to 66°F in summer. Set your thermostat to begin cooling the room 30 minutes before you plan to sleep so it reaches the target temperature by bedtime. If you share a bed with a partner who runs colder, a dual-zone electric blanket allows each side to be controlled independently.

Upgrade Your Sheets for Summer Pregnancy

Your sheets are the largest surface in direct contact with your skin throughout the night. Their thermal properties directly affect how hot you feel. The best options for hot-sleeping pregnant women:

Bamboo Viscose Sheets

Bamboo fiber is naturally moisture-wicking and has a higher breathability than most cotton weaves. Bamboo Bay Organic Bamboo Sheets ($89–$149) and Cosy House Collection Bamboo Sheets ($45–$90) are popular options. Bamboo sheets feel cool and silky to the touch and maintain that quality throughout the night better than most microfiber options.

Percale Cotton Sheets

Percale weave (one-over-one-under) creates a tighter, crisper fabric than sateen (four-over-one-under). Percale cotton feels cool and fresh rather than silky-smooth. It is more breathable than sateen. Look for thread counts of 200 to 400 — higher is not better for cooling since very high thread counts use more strands that trap heat.

Performance Cooling Sheets

Bedgear Dri-Tec Performance Sheets ($149–$229) use moisture-wicking performance fabric designed for athletic use. They dry 4x faster than cotton and are particularly effective for women who sweat heavily at night.

Choose the Right Pregnancy Pillow for Summer

Full-body pregnancy pillows add warmth because they cover a significant portion of your body surface. A U-shape pillow, in particular, wraps around both sides and can increase perceived temperature noticeably in summer. If you are buying a new pillow, specifically look for one with an ice-silk, bamboo, or jersey-knit cooling cover. If you already have a pregnancy pillow you love, purchasing a replacement cooling cover is often more economical than buying a new pillow.

Fan Setup for Maximum Cooling Effect

A fan produces evaporative cooling by accelerating the evaporation of sweat from your skin. Even in a warm room, this can lower perceived temperature by 5 to 8°F. A small 6-inch bedside fan pointed at your upper body from the nightstand distance is effective. Alternatively, a tower fan in the corner of the room on a medium setting provides more diffuse cooling that fills the room without directional air blasting at your face. For maximum summer effectiveness in a room without air conditioning: run a box fan in one window blowing in during the coolest hours of the night (typically midnight to 5am) and another fan in a second window or door creating a cross-ventilation path. Close the windows and blinds during the day to prevent hot air from entering.

Pre-Sleep Cooling Techniques

A lukewarm shower or bath 60 to 90 minutes before bed is one of the most effective physiological sleep inducers. During the shower, your body absorbs warmth and directs blood to the skin surface to cool. After you step out, the accelerated heat dissipation from your skin causes a drop in core body temperature — the same type of drop that normally initiates sleep. Note the timing: the benefit is from the cooling that happens after the shower, not during it. This is why the shower should be lukewarm, not hot — a hot shower extends the warming phase and delays the cooling phase. If you are past 30 weeks and a bath sounds more appealing than a shower, keep the water below 98°F. Avoid hot tubs and saunas entirely during pregnancy.

Other pre-sleep cooling techniques: a damp, cool cloth on the back of the neck and wrists for 10 minutes; a cool pillow spray or gel pad; freezing a thin cotton cloth and placing it in the bed for a few minutes before getting in. These are short-term but can make the initial minutes of lying down less oppressively warm.

Hydration Strategy for Summer Pregnancy Sleep

You need more water in summer pregnancy than at any other time — the combination of increased pregnancy fluid needs (ACOG recommends 8 to 12 cups daily) and summer sweat losses means dehydration risk is real. However, drinking most of your fluids in the evening directly increases nighttime bathroom trips, compounding an already disrupted sleep. The solution: front-load hydration. Aim to consume most of your daily fluid intake between 7am and 5pm. Have a small glass of water with dinner. Keep a small glass on your nightstand for overnight sips. This approach maintains adequate hydration without flooding the bladder at 2am.

Clothing and Pajama Choices for Summer Pregnancy Sleep

Loose, light cotton or bamboo nightwear allows air circulation around the body. Fitted synthetic fabrics trap heat against the skin. If you run very hot, sleeping in just a lightweight cotton tank top is reasonable. Avoid sleeping completely uncovered if your bedroom reaches 68°F or below — the body still needs some insulation to maintain sleep temperature once you have cooled down in the second half of the night.

When to Mention Heat Sensitivity to Your OB-GYN

Talk to your OB-GYN if: you are experiencing heat-related symptoms during the day such as dizziness, rapid heartbeat, or difficulty catching your breath; you are in an environment without reliable air conditioning and the daytime temperature regularly exceeds 95°F; you have noticed significant ankle swelling (edema) that is not improving with elevation — heat causes vasodilation that can worsen pregnancy-related edema; or you feel persistently unwell when warm rather than just uncomfortable. See our mattress firmness guide if an older or too-firm mattress is adding to your summer sleep discomfort.