Sleep During Pregnancy: A Trimester-by-Trimester Guide
Sleep changes at every stage of pregnancy — from first-trimester exhaustion driven by progesterone to third-trimester challenges with position, restless legs, and heartburn. This guide covers what to expect, the evidence-based sleep position guidance, and practical strategies for every stage.
Important: Educational Information Only
This guide is for general educational purposes only. Always discuss sleep concerns, symptoms, new or changing symptoms, and sleep position guidance with your midwife or GP. Individual circumstances vary significantly during pregnancy, and personalised medical advice from your healthcare team always takes priority over general guidance. If you are experiencing any of the red flag symptoms listed on this page, contact your midwife or GP immediately — do not wait for your next scheduled appointment.
Sleep by Trimester
Sleep challenges change significantly across the three trimesters. Select your current trimester to see what is normal at this stage and what helps most.
Weeks 1-13
First Trimester: Exhaustion, Nausea, and Frequent Urination
Progesterone-driven fatigue
Progesterone levels rise sharply in early pregnancy, causing profound daytime fatigue and increased sleep need. Rest when you can — this is a genuine biological need, not laziness. The fatigue typically improves significantly by the end of the first trimester as the body adjusts.
Frequent urination
hCG and increased blood volume cause the kidneys to work harder from the earliest weeks of pregnancy. Reducing fluid intake in the 2 hours before bed can reduce night-waking frequency, while maintaining adequate hydration earlier in the day. This symptom typically eases in the second trimester before returning in the third.
Nausea affecting sleep
Morning sickness (which often affects evening and night as well) can interfere with sleep onset and cause middle-of-night waking. Small, bland, easily digested meals in the evening and a small snack before bed can help stabilise blood sugar and reduce nausea. Keeping crackers on the bedside table for middle-of-night nausea is a commonly reported practical strategy.
Sleep position
In the first trimester, sleep in whatever position is comfortable. The SOS (sleep on your side) guidance from the Heazell et al. research applies from 28 weeks — in the first trimester, the uterus is still within the pelvis and position does not affect placental blood flow. Sleep as you naturally prefer.
Weeks 14-27
Second Trimester: Often the Best Sleep of Pregnancy
Improved sleep quality
The worst of first-trimester fatigue and nausea typically settles by week 14-16. Energy often returns and sleep becomes more restorative. This is a good time to establish consistent sleep habits that will be beneficial in the more challenging third trimester.
Growing bump and position
By the late second trimester, the growing bump begins to affect sleeping comfort. Starting to sleep on your side (if you do not already) becomes more natural and comfortable. Many women begin using a pillow between the knees in the second trimester to reduce hip and lower back discomfort — this is a good habit to establish before the third trimester when it becomes more important.
Heartburn beginning
Progesterone relaxes the lower oesophageal sphincter, allowing stomach acid to reflux more easily. This typically worsens progressively through the second and third trimesters as the growing uterus puts upward pressure on the stomach. Sleeping with your head elevated (using an extra pillow or a wedge pillow) and avoiding large meals close to bedtime are the most effective positional strategies. Discuss antacid options with your midwife or GP if heartburn is significantly disrupting sleep.
Preparing for T3
The second trimester is a good time to acquire a pregnancy pillow if you plan to use one, and to begin the habit of sleeping on your left side if you are a back or right-side sleeper. Establishing these habits before the third trimester — when they become more practically important — makes the transition smoother.
Weeks 28-40+
Third Trimester: The Most Challenging Sleep Stage
Sleep position from 28 weeks
The Heazell et al. (2019) research supports going to sleep on your side from 28 weeks. See the full explanation in the Sleep Position section below. Left-side sleeping is often more comfortable and may have additional benefits for placental blood flow. Right-side sleeping is also acceptable — the guidance is about avoiding falling asleep on your back, not which side you sleep on.
Restless legs syndrome
RLS affects approximately 15-25% of pregnant women and is most common in the third trimester. The uncomfortable crawling or tingling sensations in the legs are typically worse in the evening and at night. See the full RLS section below. Discuss with your midwife — iron levels are a treatable common cause during pregnancy.
Heartburn and reflux
Heartburn is often most severe in the third trimester as the uterus is at its largest. Sleeping with your upper body elevated (wedge pillow or propped head end of mattress), avoiding food within 2-3 hours of bed, and sleeping on your left side (which positions the stomach below the oesophagus) all help. Safe antacids are available — discuss options with your midwife or GP.
Anxiety and sleep
Anxiety about labour, parenthood, and the baby’s wellbeing commonly peaks in the third trimester and significantly disrupts sleep. Distinguishing normal anticipatory anxiety from clinical anxiety is important. If anxiety is severe or significantly impacting daily function as well as sleep, discuss it with your midwife — antenatal anxiety is common, well-recognised, and well-treated. Brief relaxation audio, guided breathing, and a consistent bedtime wind-down routine help many women manage normal anticipatory anxiety at night.
Sleep Position in Pregnancy: The SOS Research Explained
Sleep position in pregnancy — particularly after 28 weeks — is the most-searched pregnancy sleep topic and also the most frequently misunderstood. The guidance is specific and the reassurance is important. This section explains the evidence accurately so you can follow it confidently and without unnecessary anxiety.
SOS — Save Our Sleep: The Heazell et al. (2019) Research
Guidance applies from 28 weeks — please read the reassurance section below as carefully as the guidance
Source: Heazell AEP et al. (2019). “Association between maternal sleep practices and late stillbirth — findings from a stillbirth case-control study.” BMJ Open, 9(6). Tommy’s Research Centre, Manchester.
Pillow Support for Sleep Comfort
Pillow between the knees
Placing a pillow between the knees when sleeping on your side reduces hip and lower back strain by keeping the pelvis in neutral alignment. This is particularly helpful from the second trimester onwards as bump weight increases. A regular pillow works; a dedicated pregnancy pillow simply makes this more comfortable.
Pillow supporting the bump
A folded pillow or wedge pillow placed under the bump when lying on your side reduces the downward pull of the uterus and relieves abdominal ligament tension. This is most useful from 28 weeks when the bump is substantial. Many women find this significantly reduces the discomfort of side sleeping.
Elevated head for heartburn
An extra pillow or wedge pillow raising the head and upper body 10-15cm reduces acid reflux by using gravity to keep stomach contents down. Sleeping on the left side while elevated is the most effective combination for heartburn relief — left-side sleeping positions the stomach below the oesophagus reducing reflux, and elevation adds gravity.
Restless Legs Syndrome in Pregnancy
Restless Legs Syndrome (RLS) — an uncomfortable crawling, tingling, or irresistible-urge-to-move sensation in the legs that worsens at rest — is significantly more common in pregnancy than in the general population. Understanding what it is and what helps reduces unnecessary distress.
15-25%
Pregnant women affected
3-4x
General population rate
T3
Most common onset
RLS in pregnancy is characterised by uncomfortable sensations in the legs (often described as crawling, tingling, aching, or an irresistible urge to move) that are worse at rest — particularly in the evening and at night — and temporarily relieved by movement. For many affected women, it is a significant cause of sleep disruption in the third trimester. The good news: pregnancy-related RLS resolves in the large majority of cases within weeks of delivery.
Likely causes in pregnancy
Management strategies
Practical Sleep Strategies for Pregnancy
Most evidence-based pregnancy sleep guidance is lifestyle-based. These strategies are safe across all trimesters unless otherwise noted, but discuss any specific concerns with your midwife or GP.
Time your fluid intake
Frequent urination is unavoidable in pregnancy but its nocturnal impact can be reduced. Maintain good hydration earlier in the day and reduce fluid intake in the 1.5-2 hours before bed. This is not about dehydrating yourself — adequate hydration is important — but about front-loading your fluid intake earlier in the day.
Manage bedroom temperature
Progesterone raises basal body temperature in pregnancy. Many pregnant women find they sleep more comfortably in a cooler room than before pregnancy. 16-19 degrees Celsius is the general recommendation; pregnant women often prefer the cooler end of this range. Lightweight bedding and a fan can help significantly.
Small meals in the evening
Large evening meals worsen heartburn and can trigger nausea. Smaller, more frequent meals — particularly in the evening — reduce the gastric pressure that drives reflux. Avoiding acidic, spicy, or fatty foods close to bedtime is additionally helpful. A small bland snack (crackers, toast) at bedtime can help if nausea is an issue.
Warm bath and wind-down
A warm (not hot) bath 30-60 minutes before bed helps reduce RLS symptoms, relaxes lower back and hip muscles strained by pregnancy posture, and facilitates the core body temperature drop that initiates sleep. Hot baths are not recommended in pregnancy — aim for comfortably warm rather than hot. Bathing is one of the most consistently useful pregnancy sleep strategies.
Screen curfew
The blue light and content-driven arousal from screens delays melatonin onset and increases alertness in late evening — at a stage when many pregnant women already have disrupted sleep architecture. A screen-free 30-60 minutes before bed, replaced with gentle reading, relaxation audio, or breathing exercises, can meaningfully improve sleep onset time.
Rest is not the same as sleep
Some sleep disruption in pregnancy is unavoidable. Reframing rest — lying down comfortably, even when not sleeping — as valuable reduces the anxiety that often accompanies sleeplessness and can make it worse. You do not need to be asleep to benefit from rest. Mindful rest, gentle breathing, or a relaxation audio can provide genuine physiological recovery even without full sleep.
Contact Your Midwife or GP Immediately
These symptoms require immediate medical contact — do not wait for your next appointment
Call your midwife, GP, or maternity unit if you experience any of the following
Sleep Calculator
Calculate Sleep Cycles Around Night Wakings
Frequent night waking is common in pregnancy. The sleep cycle calculator can help you find the best time to set an alarm around your natural wake-up pattern.
Open Sleep Cycle CalculatorFrequently Asked Questions
What is the best sleeping position during pregnancy?
From 28 weeks, the guidance from the Heazell et al. (2019) research (Tommy’s Research Centre) is to go to sleep on your side — either left or right. Left-side sleeping is often preferred because it may improve blood flow to the placenta and kidneys, positioning the uterus away from the large blood vessels. However, right-side sleeping is also acceptable, and the most important aspect of the guidance is avoiding falling asleep on your back after 28 weeks, not which specific side you choose. Before 28 weeks, sleep in whatever position is comfortable — the uterus is still within the pelvis and position does not affect placental blood flow in the first and most of the second trimester. In all trimesters, a pillow between the knees reduces hip and lower back strain and improves comfort when sleeping on your side. A pillow supporting the bump from below is additionally helpful in the third trimester.
Is it safe to sleep on your back when pregnant?
After 28 weeks, the current guidance is to avoid going to sleep on your back. The Heazell et al. (2019) study found an association between falling asleep on your back after 28 weeks and a higher rate of late stillbirth (odds ratio approximately 2.3), leading to the SOS (Save Our Sleep) campaign recommendation. The critical reassurance — which is as important as the guidance itself — is that this applies to the position you fall asleep in, not the position you wake up in. If you wake during the night and find yourself on your back, this is not harmful. Simply return to your side to go back to sleep. The research was based on the going-to-sleep position, and it is not physically possible or necessary to consciously maintain sleep position throughout the night. The guidance is precautionary and sensible: settle on your side as you fall asleep from 28 weeks, do not worry about rolling during sleep, and discuss any concerns with your midwife.
Why can’t I sleep during pregnancy?
Pregnancy disrupts sleep through a different combination of mechanisms at each stage. In the first trimester, progesterone-driven fatigue and daytime sleepiness coexist with poor night sleep quality from frequent urination and nausea. In the second trimester, sleep often improves significantly — this is the period when many women feel most themselves. In the third trimester, physical discomfort from the bump, the return of frequent urination, heartburn from uterine pressure on the stomach, restless legs syndrome (affecting 15-25% of pregnant women, usually from iron deficiency), baby movements at night, and anxiety about labour all combine to create the most challenging sleep period of pregnancy. Practical strategies — timing fluid intake, sleeping with the head elevated for heartburn, pillow positioning, warm baths for RLS, and a consistent wind-down routine — address the most manageable causes. Some degree of sleep disruption in the third trimester is nearly universal and accepting it as normal (rather than fighting it with anxiety) is itself a meaningful strategy. Discuss significant sleep disruption with your midwife, particularly if RLS is severe or if sleep deprivation is impacting daily function.
