Sleep in pregnancy: what changes and why

Q: Why am I so tired in early pregnancy even though I am sleeping?

Rising progesterone in early pregnancy has a sedating effect, so you can feel wiped out even after a full night in bed. Your body is also making more blood and handling shifts in blood pressure and blood sugar, which all add to the load. This kind of tiredness is very common in the first trimester and often eases off in the second trimester.

Q: Is it safe to sleep on my back during pregnancy?

After 28 weeks, falling asleep on your back has been linked to a higher risk of stillbirth, so it is recommended you settle on your side from that point. If you wake up on your back during the night, just roll back onto your side. Either the left or right side is safe. Before 28 weeks, back-sleeping is generally lower risk, though getting used to your side earlier on is a good habit to build.

Q: What can I do practically to sleep better in the third trimester?

Pillows can help a lot: try one under your bump, one between your knees, and one at your back to ease pressure when you are on your side. Limiting drinks close to bedtime may cut down nighttime trips to the toilet. Keeping caffeine low through the day, aiming for under 200mg in total, and skipping it in the evenings can help too. A calming routine before bed, putting screens away for an hour beforehand, and gentle daytime movement like walking are all worth a try. If sleep will not come, getting up briefly to do something quiet in another room often works better than lying there awake.

Q: Is it normal to have vivid dreams or feel anxious about birth during pregnancy?

Yes, vivid dreams and nightmares are common in pregnancy, especially in the third trimester. Worry about the birth or becoming a parent can interrupt sleep as well. If anxiety feels constant, distressing, or is really affecting your sleep or daily life, speak to your midwife or GP. Mental health support around pregnancy is available, and your care team can point you towards it.

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Sleep rarely stays the same across a pregnancy. The tiredness that arrives early on in a pregnancy can feel surprising in its intensity, and the broken nights that come later have their own challenges. Understanding what tends to shift across each trimester, and why, can make it a little easier to work with.

What happens to sleep in early pregnancy

Feeling wiped out in the first 12 weeks is very common. A big part of it comes down to progesterone, a hormone that rises in early pregnancy and has a sedating effect. It can leave you with a heavy tiredness and sleepiness that feels hard to push through.¹⁰

There is also a lot going on behind the scenes. Your body makes more blood to support the pregnancy, and your blood pressure and blood sugar can dip alongside it. These shifts add to the tiredness you are already feeling.¹

Nights do not always bring more rest. Needing to pee more often is a common reason sleep gets broken in early pregnancy, and it tends to continue as the pregnancy progresses. It is worth knowing that this is a normal part of how your body changes rather than something to worry about.¹¹

Third trimester sleep: why it gets harder and what can help

From around 28 weeks, your growing bump makes it harder to find a comfortable position. Aches and pains, especially in your back and hips, can make it hard to settle or stay asleep. Turning over in bed, something you normally do without thinking, starts to take real effort.³

Other things tend to interrupt sleep in the third trimester too: the baby's movements, heartburn, leg cramps, and more frequent trips to the toilet. If heartburn is severe or keeps coming back, raise it with your midwife or GP rather than dealing with it alone.²

Some people notice more vivid dreams at this stage, and worries about birth or becoming a parent can keep you awake too. If that worry feels constant or starts affecting your daily life, speak to your midwife or GP. Mental health support around pregnancy is available, and your care team can point you towards it¹²

Sleep position after 28 weeks

From 28 weeks, the safest position to fall asleep in is on your side. Falling asleep on your back in the third trimester has been linked to a higher risk of stillbirth. This counts for daytime naps as well as nights. It is one of the most important changes to make in late pregnancy.¹³

Either side is safe. The left side gets mentioned a lot because it can support blood flow, though your right side is fine too and far better than your back. What matters most is avoiding your back after 28 weeks. The side you pick is up to you.⁵

What may help you sleep more comfortably

Pillows can make a real difference when you are sleeping on your side. Try one under your bump, one between your knees, and one behind your back. This spreads the weight and takes some pressure off your hips and lower back.¹⁴

A calming routine before bed can help too. A warm bath (warm, not hot, as very hot water is not recommended in pregnancy), reading, and putting screens away for an hour before bed are all worth a try. The blue light from phones and tablets can get in the way of your body winding down for sleep.⁶

To cut down on nighttime trips to the toilet, try limiting drinks in the hour or so before bed. Easing off caffeine in the evening can help as well. Caffeine is a stimulant found in tea, coffee, and some fizzy drinks, and the recommended limit in pregnancy is under 200mg a day in total, not just in the evenings. If you are not sure whether your intake sits within that, your midwife or GP can advise.⁸

Gentle movement during the day, like walking, can support better sleep at night. It is usually best to keep harder exercise away from bedtime. If you have any pregnancy complications, or you are not sure whether a particular activity suits you, check with your midwife before changing your routine.⁹

If you are lying awake and sleep will not come, getting up and doing something calm in another room, like reading, until you feel sleepy again often works better than staying put and trying to force it.⁷

Every pregnancy is different. If sleep problems keep up, start affecting your mood, or you have concerns about any of the physical symptoms here, your midwife or GP is the right first contact.

Frequently Asked Questions

Why am I so tired in early pregnancy even though I am sleeping?

Is it safe to sleep on my back during pregnancy?

What can I do practically to sleep better in the third trimester?

Is it normal to have vivid dreams or feel anxious about birth during pregnancy?

Sources

[1] First Trimester Fatigue

The body produces more blood to support the developing pregnancy, and this can be accompanied by a potential drop in blood pressure and lower blood sugar levels.
[2] How can I get more sleep in pregnancy?

Common reasons for sleep disruption in the third trimester include the baby's movements, heartburn, leg cramps, more frequent trips to the toilet, and difficulty turning over.
[3] How can I get more sleep in pregnancy?

From around 28 weeks, the growing bump makes it difficult to find a comfortable sleeping position. Aches and pains, including back pain and hip pain, are common.
[4] tommys.org

If you wake up on your back, simply roll back onto your side. The position you fall asleep in is the one you maintain for the longest.
[5] tommys.org

Sleeping on your side is the recommended and safest position. The left side is often cited as best because it can improve blood flow, but either side is safe and better than sleeping on your back.
[6] How can I get more sleep in pregnancy?

A relaxing bedtime routine can help, including a warm bath, reading a book, and avoiding screens for an hour before bed, as the blue light can interfere with sleep.
[7] How can I get more sleep in pregnancy?

If you cannot sleep, getting up and doing something calm in another room, such as reading, until you feel sleepy again can be more effective than staying in bed.
[8] How can I get more sleep in pregnancy?

To reduce nighttime trips to the toilet, try limiting drinks in the hour or so before bed. Avoiding caffeine in the evening is also helpful; the recommended limit during pregnancy is under 200mg per day in total.
[9] How can I get more sleep in pregnancy?

Gentle exercise during the day, such as walking, can support better sleep at night; it is best to avoid vigorous exercise close to bedtime.
[10] First Trimester Fatigue

Rising levels of progesterone in early pregnancy have a sedating effect, contributing to feelings of tiredness and sleepiness.
[11] Insomnia: pregnancy tips for better sleep

An increased need to pass urine is another reason for disrupted sleep in early pregnancy. Progesterone can relax the bladder muscles, and as the uterus grows it places direct pressure on the bladder.
[12] Sleep Problems in Pregnancy

It is normal to have more vivid dreams or nightmares, sometimes about the baby or giving birth. Anxieties about the upcoming delivery or becoming a parent can keep you awake.
[13] tommys.org

From 28 weeks, the safest sleeping position is on your side. Going to sleep on your back in the third trimester has been linked to an increased risk of stillbirth. This applies to both nighttime sleep and daytime naps.
[14] Week 27 - Your pregnancy journey

Placing a pillow under the bump, between the knees, and behind the back can help relieve pressure and make side-sleeping more comfortable.