How to Change Sleeping Positions During Pregnancy

If you’re pregnant, you already know you can’t stay in one position for long. The good news: you don’t need to “train” yourself or do anything complicated. Most people end up with a simple approach—sleep on your side, often called SOS. Then you make small pillow adjustments so you can switch sides without feeling like you’re fighting your own body.

Here’s an easy, repeatable routine—step by step—for the first 3 months, second trimester, and third trimester.

Why side sleeping (SOS) shows up as the go-to position in pregnancy

Sleep on your side comes up for one main reason: it’s often the easiest way to feel comfortable, and it supports better circulation for you and your baby. That’s why SOS gets described as the best “default” position.

You’ll also hear a stronger push for side sleeping later on. One line in the research notes says that in the third trimester you should go to sleep on your side, and that research suggests side sleeping in the third trimester is safer for baby. By the time you’re in the later months, the goal is still comfort—but it’s also about building safer sleep habits.

How to shift sleeping positions without strain: a simple step-by-step routine

The goal isn’t a hard flip. Move slowly, and reset your pillows so your body feels supported.

Try this routine the next time you wake up uncomfortable (or when you’re settling in for the night):

1. Pause for a breath.

Don’t roll right away. Take a second—quick movements can make your back and belly feel worse.

1. Get your “base” right first.

Aim for side sleeping (SOS) with pillows in the key spots (placement is below). If your pillows are off, you’ll notice quickly.

1. Use your legs to guide the roll.

To switch from one side to the other, start by moving your knees. Many people find it’s easier on the hips.

1. Roll just enough to switch, then stop.

You don’t have to land perfectly on the first try. Get to the new side first, then adjust.

1. Re-set the support points.

After you switch sides, put:

• the pillow between your knees in the same place on the new side
• the belly support in a comfy spot under/around your belly

1. Check quickly: do you feel pressure?

If your top hip feels jammed, your lower back feels pulled, or your belly feels unsupported, the issue is usually one small pillow adjustment—not starting over from scratch.

That’s the core method. Repeat it each time you wake up or need to shift.

Pillow setup for side sleeping: between knees and under the belly

Pillows are what make SOS feel workable. A common setup includes:

• a pillow between your knees
• one under your belly (abdomen)

Here’s what they’re doing:

• The between-the-knees pillow helps keep your hips from twisting.
• The under-belly pillow supports your abdomen so your torso doesn’t sink or feel stretched.

The research notes also mention using pillows and towels to shift sides “without strain.” You can add support for your back and extra comfort for your belly if you need it.

Practical tip: if you tend to wake up and your pillows have “migrated,” try starting the night with them positioned where you’ll want them. It saves you from fighting them later.

How to change sleeping positions during pregnancy first trimester (first 3 months)

In the first few months, your body is changing quickly, but you might not feel “stuck” yet. The main goal here is to set up a comfortable side-sleeping routine and learn how to reset it without overthinking.

For sleeping position during pregnancy first 3 months, try this:

• Start with SOS (sleep on your side).
• Use the pillow between your knees and one under your belly right away, even if you feel okay without them.
• When you wake up (or notice yourself rolling), switch sides using the routine:
• pause
• roll slowly
• re-place the knee pillow
• re-place the belly pillow

If you’re not sure which side feels best, pick the one that feels most comfortable and consistent. The routine stays the same either way: support first, then adjust.

And if you’re worried you’ll get stuck on one side, don’t. Once you’re used to resetting the pillows, switching gets a lot easier.

How to change sleeping positions during pregnancy second trimester

This is when many people start to feel that their older sleep habits don’t work as well. Guidance for side sleeping becomes more relevant here, but the overall approach stays the same: keep using SOS.

For how to change sleeping positions during pregnancy second trimester, keep it simple:

1. Stick with side sleeping for most of the night.
2. Make small switches instead of big rolls.
3. Re-set pillows every time you switch sides.

If you notice your back aching, add a bit more support so you’re not twisting. The research notes mention pillow/towel help for back support and belly comfort, so it’s reasonable to customize—just keep the main SOS supports in place.

Also, don’t wait until you’re completely uncomfortable. If you feel yourself sliding out of a supported position, switch and reset while it still feels easy.

How to change sleeping positions during pregnancy third tri (third trimester)

In third trimester, the advice gets more firm: in the third trimester you should go to sleep on your side, including night sleep and daytime naps. The research notes frame this as part of safer guidance, not just preference.

So, when you’re asking about how to change sleeping positions during pregnancy third tri, match the urgency:

• Plan your sleep around SOS from the start of the night.
• Use your pillow setup:
• between knees
• under belly (abdomen)
• If you wake up and need to switch sides, use the same routine:
• pause
• slow roll
• re-set knee pillow
• re-set belly support

Daytime naps matter too. If you doze off on your back or in a non-side position, it’s usually not “wrong forever,” but in third trimester your best move is to return to side sleeping as soon as you notice.

What sleeping positions should I avoid while pregnant?

This is one of the PAA-style questions people ask most. In the research notes you referenced, there aren’t specific “avoid this exact position” rules listed.

Instead, the safest framing based on the notes is:

• Avoid positions that make you uncomfortable, especially if your back or belly feels strained.
• Avoid staying in non-side positions for long periods in third trimester, since guidance emphasizes side sleeping for night sleep and naps.

If you want a truly clear, personalized list, ask your clinician. What “avoid” means can vary depending on your symptoms and comfort.

What happens if you accidentally sleep on your right side while pregnant?

This question is also in the PAA list you provided: “What happens if you accidentally sleep on your right side while pregnant?”

The research notes you shared don’t include a specific warning or outcome. In that case, the most useful approach is practical and calm:

• If you realize you’re on your right side, gently shift back into your supported SOS setup (pillow between knees, belly supported).
• Don’t panic. Most of the time, it’s about getting back to what helps you feel supported and aligned with side-sleeping guidance.

If you feel anxious—especially in third trimester—ask your clinician for reassurance based on your pregnancy and what feels right for your body.

Troubleshooting: when you can’t stay in one position (naps and nighttime)

Even with the best pillow setup, pregnancy sleep can still be messy. You’ll roll, you’ll adjust, and your body will change its mind.

Here are ways to handle it without losing the whole night:

If you wake up on an “off” side

Use the routine:

• pause
• slow roll
• re-set between-knees pillow
• re-set under-belly support

The goal isn’t perfection. It’s quick support so you can fall back asleep.

If you struggle during naps

In third trimester, side sleeping should include daytime naps too. When you lie down for a nap:

• set your pillows before you fall asleep if you can
• plan to reset your pillows if you wake up twisted

If your body keeps sliding or your pillows move

That’s common. Try one small change:

• reposition the pillows so they start where your body naturally settles
• if you use towels as suggested in the research notes, use them to “fill gaps” so your support doesn’t slide away

You’re building a setup that works with how you actually move in sleep.

When to ask a clinician for personalized sleep advice

You shouldn’t have to sort this out on your own. Ask your clinician (or midwife) for personalized advice if:

• you can’t get comfortable even with SOS and pillow support
• you feel worried or anxious about which side you’re sleeping on
• your sleep problems are persistent and starting to affect your daily life
• you’re unsure what to avoid based on your own pregnancy symptoms

A clinician can also help you interpret what “side sleeping” means for your specific situation—especially if something else is going on (pain, reflux, or other issues).

If you’re sharing a bed, it can help to loop in your partner or caregiver too, so the routine is easier to follow.

Share this guide with a partner or caregiver, try the pillow routine tonight, and then adjust as your comfort changes.