How Baby Sleep Patterns Change Between Trimester 2 and 3
Pregatips | January 16, 2026 10:39 PM CST
Being pregnant feels really amazing, particularly when you get to feel those sweet little movements and tiny kicks all the time. But one of the most fascinating things is the sleeping pattern of the foetus inside your womb. They actually develop sleeping patterns even before they’re born, and those patterns change as they grow. If you've ever wondered why some days your baby seems calm and other days extremely active, these changes in sleep patterns could be the reason.
Below, you'll understand the changes between the second and third trimester, why they happen, and how you can support your own comfort and emotional health along the way.
What’s Baby’s Sleep Like in the Second Trimester?
In the second trimester (week 13 to 27), your baby gets a lot more active, but their sleep is still getting there. Around weeks 18 to 20, they begin to form sleep patterns.
At this point, babies sleep around 14 to 16 hours a day, usually in short bursts. You probably won’t even feel these little sleep shifts as the movements are very subtle.
What to expect in the second trimester:
Your baby’s brain undergoes rapid development at around 28 weeks of pregnancy, when you enter the final trimester. This indicates that they now have a proper sleep cycle, similar to that at birth, with REM and non-REM sleep.
Your baby now responds to light, sound, and even your emotions as their brain continues to develop. These responses can influence how they move, which might make them seem awake.
These significant transitions occur because:
How Much Does Your Baby Sleep in the Third Trimester?
Surprisingly, your baby still sleeps for about 16 to 20 hours regularly in the third trimester. What changes is how they sleep.
What improves:
Why Do You Sense More Activity at Night?
If your baby seems more active at night, you're not imagining it. This is extremely common.
Reasons:
How Do Your Emotions Influence Your Baby’s Sleep?
Your baby can sense:
What Are the Rare Changes in Sleep Pattern During the Third Trimester?
Here are a few interesting but rarely discussed changes:
1. Light Sensitivity Develops
Your baby may turn towards the bright light outside the womb. This responsiveness shows developing sleep-wake awareness.
2. Daily Stretching
Stretching helps your baby practice muscle control. This activity often happens after a sleep cycle.
3. Hiccup-Like Movements
These rhythmic jumps often occur during light sleep and are absolutely fine.
4. Sync of Heartbeat
Your baby's heartbeat can respond to your voice and emotions, influencing sleep and wakefulness.
What Are the Signs to be Worried About?
While it’s normal for movements to change, you should see a doctor if:
Figuring out your baby’s sleep habits can really make you feel more secure and in sync. Talking about these experiences with your partner can make your bond stronger and get you both ready for the incredible journey of parenthood.
Directly communicate about your fears and anxiety with your family or doctor. Pregnancy emotions are absolutely normal, and reassurance makes you feel better.
Your baby’s sleep pattern becomes more active and structured as you transit from the second to the last trimester. These changes indicate a stronger brain development, healthy growth, and improved awareness. By listening to your baby’s movements, understanding these patterns, and taking care of your mental and physical well-being, you get ready for a smoother and more confident transition into the final stage of conception.
Whether you’re pregnant, a new mom, or navigating postpartum, you don’t have to do it alone. Join our support group to connect, share, and support one another.
FAQs on How Baby Sleep Patterns Change Between Trimester 2 and 3
Can the consumption of something sweet increase foetal movement?
Yes, your baby might become alert for a moment when there’s a slight rise in your blood sugar. This is often used during kick counts to encourage movements.
Should I be worried if my baby moves each day differently?
Minor variations are absolutely fine. You should only worry if there’s a sudden, significant change in movement.
Do babies maintain a day-night rhythm inside the womb?
Not really. Their sleep schedule depends on your hormones, how you move, and how their brain grows, not external time. They only start to get a normal day-night rhythm after they’re born.
Below, you'll understand the changes between the second and third trimester, why they happen, and how you can support your own comfort and emotional health along the way.
What’s Baby’s Sleep Like in the Second Trimester?
In the second trimester (week 13 to 27), your baby gets a lot more active, but their sleep is still getting there. Around weeks 18 to 20, they begin to form sleep patterns.
At this point, babies sleep around 14 to 16 hours a day, usually in short bursts. You probably won’t even feel these little sleep shifts as the movements are very subtle.
What to expect in the second trimester:
- Sleep cycles are irregular.
- Movements are light and sometimes hard to feel.
- The nervous system is still under development.
- Early REM (Rapid Eye Movement) sleep begins around week 25, which is important for brain development.
Your baby’s brain undergoes rapid development at around 28 weeks of pregnancy, when you enter the final trimester. This indicates that they now have a proper sleep cycle, similar to that at birth, with REM and non-REM sleep.
Your baby now responds to light, sound, and even your emotions as their brain continues to develop. These responses can influence how they move, which might make them seem awake.
These significant transitions occur because:
- The nervous system gets more stabilised
- The brain grows up to 50% in the third trimester
- Sensory organs become sharper
- Babies start practising breathing movements during sleep
How Much Does Your Baby Sleep in the Third Trimester?
Surprisingly, your baby still sleeps for about 16 to 20 hours regularly in the third trimester. What changes is how they sleep.
What improves:
- Longer sleep cycles
- Clearer awake periods
- More noticeable REM patterns
- Stronger reactions during awake moments
Why Do You Sense More Activity at Night?
If your baby seems more active at night, you're not imagining it. This is extremely common.
Reasons:
- Your body's movement during the lull helps your baby to sleep.
- Hormonal changes can stimulate foetal activity.
- You're more aware and still at night, so the foetal movement feels more intense.
How Do Your Emotions Influence Your Baby’s Sleep?
Your baby can sense:
- Heart rate changes
- Stress hormones
- Relaxation signals
What Are the Rare Changes in Sleep Pattern During the Third Trimester?
Here are a few interesting but rarely discussed changes:
1. Light Sensitivity Develops
Your baby may turn towards the bright light outside the womb. This responsiveness shows developing sleep-wake awareness.
2. Daily Stretching
Stretching helps your baby practice muscle control. This activity often happens after a sleep cycle.
3. Hiccup-Like Movements
These rhythmic jumps often occur during light sleep and are absolutely fine.
4. Sync of Heartbeat
Your baby's heartbeat can respond to your voice and emotions, influencing sleep and wakefulness.
What Are the Signs to be Worried About?
While it’s normal for movements to change, you should see a doctor if:
- You encounter less activity in foetal movement
- Less than 10 movements in 2 hours during your baby's active time
- Complete absence of movement
- Regularly track your baby’s movement
- For better comfort, manage your sleep patterns
- Notice the patterns of both quiet times and active times
- Share with your loved ones about what’s bothering you
- Call your doctor if you encounter any abnormal movement patterns
Figuring out your baby’s sleep habits can really make you feel more secure and in sync. Talking about these experiences with your partner can make your bond stronger and get you both ready for the incredible journey of parenthood.
Directly communicate about your fears and anxiety with your family or doctor. Pregnancy emotions are absolutely normal, and reassurance makes you feel better.
Your baby’s sleep pattern becomes more active and structured as you transit from the second to the last trimester. These changes indicate a stronger brain development, healthy growth, and improved awareness. By listening to your baby’s movements, understanding these patterns, and taking care of your mental and physical well-being, you get ready for a smoother and more confident transition into the final stage of conception.
Whether you’re pregnant, a new mom, or navigating postpartum, you don’t have to do it alone. Join our support group to connect, share, and support one another.
FAQs on How Baby Sleep Patterns Change Between Trimester 2 and 3
Yes, your baby might become alert for a moment when there’s a slight rise in your blood sugar. This is often used during kick counts to encourage movements.
Minor variations are absolutely fine. You should only worry if there’s a sudden, significant change in movement.
Not really. Their sleep schedule depends on your hormones, how you move, and how their brain grows, not external time. They only start to get a normal day-night rhythm after they’re born.
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