Week 28: Third Trimester Begins

Large aubergine (~25cm crown-rump)·Last reviewed: 25 April 2026

Quick answer

Welcome to the third trimester. At week 28, your baby shows REM-like sleep activity during active sleep. According to Nuhah's pregnancy guide, the brain is developing folds and grooves, and body fat is increasing rapidly.

Baby development at week 28

The third trimester begins. REM-like sleep activity starts, and your baby shows rapid eye movements during active sleep. Body fat is increasing, filling out the wrinkled skin. The brain is developing folds and grooves that dramatically increase its surface area. The baby weighs about 1,100g and is around 38cm from head to toe. Movements are strong and frequent. The baby can hiccup, which you may feel as rhythmic, repetitive movements.

Your body this week

The third trimester brings new challenges: backache, breathlessness, heartburn, and difficulty sleeping. Your uterus is now well above your navel. Braxton Hicks contractions may become more noticeable. You might feel breathless as the uterus pushes against your diaphragm. Antenatal appointments become more frequent from now on (every 2-4 weeks). The nesting instinct may kick in.

Things to do this week

Start kick counting - Nuhah's kick counter tracks movements from week 28

Your midwife appointments become more frequent from now

Begin packing your hospital bag (aim to have it ready by week 36)

Attend antenatal classes if you haven't already

Start thinking about childcare arrangements if both parents plan to return to work

Frequently asked questions

When should I start counting kicks?

From week 28 onwards. Get to know your baby's normal pattern of movement. There is no set number of kicks to count - what matters is that your baby's movements are consistent with their usual pattern. If you notice reduced movement, contact your maternity unit straight away.

What happens in the third trimester?

The third trimester (weeks 28-40) is focused on growth and final development. Your baby gains most of their weight during this period, the lungs mature, and the brain develops rapidly. Antenatal appointments increase in frequency and you will prepare for birth.

What should I pack in my hospital bag?

Key items include comfortable nightwear, toiletries, snacks and drinks, phone charger, comfortable going-home clothes, nappies and cotton wool, baby clothes (vests, sleepsuits, hat), and a car seat for the journey home. Nuhah's hospital bag checklist blog post covers this in detail.

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