How to protect her sleep in the third trimester

By the third trimester, a full night of uninterrupted sleep is mostly a memory. The bump makes every position uncomfortable, the baby moves at 3am, heartburn strikes at 2am, and bathroom trips are constant. You can't fix any of that — but you can build an environment that makes nights significantly more manageable.

Why sleep becomes so difficult in the third trimester

From around week 28 onwards, a combination of physical and physiological factors conspire against sleep. The growing uterus puts pressure on the bladder, making multiple night trips unavoidable. Lying flat compresses the inferior vena cava — the large vein returning blood to the heart — which is why midwives recommend she sleeps on her side, ideally the left. Heartburn worsens as the baby pushes up against the stomach. Restless legs syndrome affects a significant proportion of pregnant people. And the baby, who has no sense of social hours, tends to be most active when she finally lies still.

None of this is fixable. The goal is reduction, not elimination.

Pillow setup that actually works

A pregnancy pillow — the long U-shaped or C-shaped kind — is not a gimmick. It supports the bump from below, keeps the hips aligned, and gives something to rest the top knee on, which reduces hip and lower back pain significantly. If you haven't already bought one, do it now.

The setup that works best for most people in the third trimester:

• Left-side lying, with the bump supported by the pillow beneath it
• A pillow between the knees to keep hips stacked and reduce sacroiliac pressure
• A slight incline if heartburn is an issue — a wedge pillow under the mattress, not just extra pillows under her head
• Your pillows on your side, not encroaching — she needs the space

Temperature and light — the changes to make tonight

Pregnant people run warmer than usual. Progesterone raises core body temperature, and the increased blood volume amplifies this. Practical adjustments:

• Drop the room temperature by one or two degrees — open a window if weather allows
• Switch to a lighter duvet on her side, or use separate duvets entirely
• Blackout blinds make a material difference, especially in summer
• Reduce screen light in the bedroom from an hour before she wants to sleep
• A small fan directed at her side of the bed, not yours, can help significantly

When snoring means something

New or significantly worsened snoring in the third trimester can be a sign of gestational sleep apnoea, which is associated with an increased risk of hypertension and other complications. If she's started snoring heavily, or waking herself up gasping, mention it to the midwife at the next appointment — don't wait. This isn't something to monitor quietly.

Building a night routine that works for both of you

You're going to be a new parent soon. Starting sleep hygiene habits now is good practice for both of you. A useful joint routine from week 28:

• Agree a rough "wind-down starts" time — and actually stick to it
• She goes to bed when tired, even if that's earlier than you — don't make her wait
• You handle any kitchen or household tasks that come up after she's in bed
• Phones out of the bedroom, or at least face-down and silenced

She's not sleeping well, and that won't fully resolve until the fourth trimester is behind you. The goal for now is making each night slightly better than it would otherwise be.

One more thing: don't complain about your sleep

You may be woken up by her getting up, by the fan, or by her restlessness. Keep this to yourself for the duration of the third trimester. She knows. She's sorry. She can't do anything about it.

For more on the third trimester week by week — including what to prepare before the due date — check the week-by-week guide, or join the Plus waitlist for weekly updates tailored to where you are in the pregnancy.