Pregnancy sleep gets harder as the bump grows, and the mattress is one of the few things you can control. What makes this page different from most condition-specific guides on this site is that there's a medical safety dimension to how you sleep during pregnancy, not just comfort. The NHS and Tommy's charity both recommend sleeping on your side from 28 weeks of pregnancy based on research linking back sleeping in the third trimester to an increased risk of stillbirth. That guidance shapes everything else on this page.
I've reviewed mattresses for pregnant buyers across all three trimesters and the pattern is clear: what feels right at 16 weeks often doesn't work at 34 weeks. The body changes fast, the weight shifts, and the mattress needs to support side sleeping specifically without creating new pressure problems at the hip and shoulder.
This page is not medical advice. The sleep position guidance below is based on published NHS recommendations and research funded by Tommy's charity (tommys.org). If you have concerns about your sleep during pregnancy, speak to your midwife, GP, or obstetrician. A mattress can support your comfort but the safety advice on sleep position comes from your healthcare team.
Sleep position in pregnancy - the safety guidance first
From 28 weeks of pregnancy, the NHS recommends going to sleep on your side. Six separate research studies have shown a link between going to sleep on your back in the third trimester and an increased risk of late stillbirth, with the MiNESS trial finding a 2.3x increase in risk for back sleepers compared to side sleepers. Tommy's #SleepOnSide campaign has raised public awareness of this research since 2017.
Left or right side are both safe. The older advice that left side is better has been softened by more recent research. What matters is being on your side when you fall asleep. If you wake up on your back during the night, don't panic - roll onto your side and go back to sleep.
Why this matters for mattress choice: if side sleeping is medically recommended from 28 weeks, the mattress needs to support that position specifically. Proper cushioning at the shoulder and hip where side-sleeping body weight concentrates, enough give in the comfort layer to prevent pressure build-up, and a surface that makes turning from one side to the other straightforward.
What construction works for pregnancy
Medium to medium-firm hybrid is the starting point for most pregnant buyers. The pocket spring base holds the pelvis level and provides the structural support the changing body weight needs. The comfort layer cushions the shoulder and hip. Between them the spine stays aligned without pressure building at the bump or ribcage.
Responsive comfort layers matter more for pregnancy than for most conditions. When you need to turn from one side to the other at 34 weeks, a mattress that responds quickly to position changes is noticeably easier to live with than dense memory foam that resists movement. Latex and responsive foam alternatives outperform standard memory foam on this specific point.
Temperature regulation becomes more important as pregnancy progresses. Hormonal changes cause temperature fluctuations, and night sweats are common in the second and third trimesters. Our hot sleepers guide covers the construction specifics in depth, but the short version: pocket springs with a breathable comfort layer handle pregnancy temperature better than dense all-foam builds.
How needs change through trimesters
First trimester: most women don't notice mattress-related discomfort yet. The bump is small and the weight shift is minimal. I mention this because some expectant parents rush to buy a new mattress based on early-pregnancy anxiety rather than actual need. If your current mattress was comfortable before pregnancy, it'll probably still work for another few months.
Second trimester: the bump becomes noticeable and side sleeping starts to feel different because there's more weight pressing into the mattress at the hip. Some women start using a pregnancy pillow in this phase. The mattress should be supporting side sleeping comfortably by this point.
Third trimester: this is where the mattress either works or it doesn't. The weight has shifted substantially, getting in and out of bed is harder, and turning between sides takes real effort. If you've been putting off the mattress question, 28 weeks is the natural deadline because the side-sleeping guidance kicks in and the mattress needs to support that position properly from here.
Brands I'd recommend for pregnancy
Simba Hybrid Pro is the mattress I'd suggest first for most pregnant buyers. The Simbatex foam responds faster than standard memory foam when you turn, and the pocket spring base provides the structural support the pelvis needs as the weight changes through the trimesters. I've had pregnant readers report that the Simba was the first mattress where turning at 34 weeks didn't feel like a wrestling match. The 200 night trial covers the full third trimester window if you time the purchase right.
If trial length matters most, Nectar Premier Hybrid offers 365 nights, the longest in the UK market. That covers most of a full pregnancy from purchase to well past birth, giving real flexibility if your needs change significantly between trimesters. The hybrid construction provides pocket spring support with a foam comfort layer at a competitive price.
Hypnia Supreme Hybrid pairs pocket springs with a latex layer and a bamboo cover. The cooling performance is a step up from standard memory foam hybrids, and for pregnant buyers dealing with second and third trimester temperature swings the latex breathability makes a real difference at the surface. 200 night trial, 15 year warranty.
Lighter pregnant buyers or anyone finding medium-firm too hard at the hip as the bump grows should look at Emma NextGen Premium. It runs softer than Simba and the foam comfort layer contours more gradually around the hip and shoulder. Not the best option for heavier builds, but for average-weight pregnant sleepers it handles the third trimester side-sleeping demands without creating new pressure problems.
Origin Hybrid Pro puts 5,700 pocket springs in a king, and for side-sleeping pregnant buyers that spring density means more precise contouring around the hip and bump. The 15 year warranty outlasts the pregnancy considerably, so you're buying a mattress that serves well beyond the condition-specific phase.
Pregnancy pillows and mattress accessories
A pregnancy pillow is one of those purchases that feels excessive until you use one. A full-length C-shaped or U-shaped pregnancy pillow supports the bump, keeps a pillow between the knees (which the NHS recommends for pelvic girdle pain relief), and props behind the back to reduce the chance of rolling onto your back during sleep.
Your standard pillow matters too. Side sleeping changes the gap between your head and the mattress, and a higher, firmer pillow than you'd normally use often works better for pregnancy side sleeping because it keeps the neck level with the spine.
For pregnant buyers who find their current mattress slightly too firm at the hip but don't want to replace it mid-pregnancy, a 5-8 cm latex or memory foam topper can add the extra cushioning side sleeping needs. A lower-cost option than a full mattress replacement, and one you can keep or remove after birth.
Verdict
Side sleeping from 28 weeks is the medical guidance. The mattress needs to support that position specifically. Medium to medium-firm hybrid with a responsive comfort layer is the construction that works for most pregnant buyers. Simba Hybrid Pro for most, Nectar for maximum trial length, Hypnia for cooling, Emma for softer builds, Origin for the highest spring count. A pregnancy pillow and a proper head pillow complete the system. And if you have specific concerns about sleep during pregnancy, your midwife is the first call to make.
