The 4th Trimester Explained in Simple Words

The first three months after your baby is born are often called the 4th trimester. It is a phase that many mothers step into without truly knowing what to expect, and that is why it can feel overwhelming, confusing, and emotionally heavy. The truth is simple. Your baby is still adjusting to a world that is completely new.

Why do we call it the 4th trimester?

During pregnancy, your baby lived in a warm, dark, constantly soothing environment. They heard your heartbeat, felt your movement, and stayed close to you every moment. Once they are born, that world changes instantly. Their body and brain need time to understand what life outside the womb feels like.

From evolution biology, we know that human babies complete a significant part of their gestation outside the womb. Their brain and nervous system grow at an extraordinary pace during these first weeks. This is why newborns need a lot of sleep, a lot of touch, and a lot of closeness.

How much do newborns sleep?

Newborns need about 16 to 18 hours of sleep in 24 hours.
But even though they sleep a lot, their sleep looks nothing like ours. They sleep differently in visible and invisible ways. You will see short naps, frequent waking, light sleep, and unpredictable patterns. Their brain is still learning how to handle longer stretches.

Short naps of 30 to 50 minutes are normal. Waking up often is normal. Needing help to fall asleep is normal. There is nothing wrong with your baby.

Why do they wake so often at night?

Newborns do not have a circadian rhythm yet. Their body does not understand the difference between day and night. This rhythm begins forming only around 10 to 12 weeks. So if your baby sleeps long stretches during the day and wakes more at night, it is not a routine problem. It is pure biology.

No amount of “setting a schedule” will change this in the early weeks. Day and night simply cannot be taught at this stage.

Why do they want to be held so much?

Because their nervous system is immature and they need womb-like care.
Your warmth, your movement, your smell, your heartbeat, and the sound of your voice help regulate your baby. Holding, rocking, feeding, swaddling, and skin-to-skin are not spoiling your baby. They are supporting the exact development their brain needs.

No jhula, crib, device, or swaddle can replace your arms. You are their safety.

Why is soothing so important?

Your touch reduces stress hormones.
Your smell comforts your baby.
Your voice calms their nervous system.
Your presence helps their brain connect pathways that support emotional security.

Soothing your baby to sleep or responding to their cries is not creating bad habits. It is creating emotional safety.

When does it get easier?

Around 10 to 12 weeks, many babies begin to:

• develop a circadian rhythm

• settle a little easier

• give longer stretches of sleep

• become more predictable

• manage slightly longer wake windows

The fog slowly lifts. Not overnight, but gently.

A message for you

The 4th trimester is a time for transition.

If this season feels exhausting, please know that you are not alone and nothing is wrong with your baby. They are behaving exactly how a newborn is supposed to behave. And you are doing far more for them than you realise.

You are their world.
You are their safety.
You are already what your baby needs.

If you want more gentle, no tears sleep support, follow along for guidance that truly respects your baby’s biology and your peace as a mother.