Third Trimester

Week 31

Your baby is the size of a Coconut

Baby Size

Coconut

Length

11.2 in (28.5 cm)

Weight

3.0 lb (1.35 kg)

Trimester

Third Trimester

Your Baby at Week 31

Your baby is the size of a coconut at 31 weeks. All five senses are now fully functional, and the pupils can react to light shining through your belly.

Key milestone: The baby can process information from all five senses. The pupils react to light. The digestive system is fully functional.

Your Symptoms

Pressure on the bladder. Difficulty finding comfortable sleep positions. Lower back pain.

Tip for This Week

Stay hydrated to reduce Braxton Hicks contractions and prevent UTIs.

Your Body at Week 31

In the third trimester, your growing uterus presses against your diaphragm, stomach, and bladder. Shortness of breath, heartburn, and frequent urination are common. Your body is producing relaxin, a hormone that loosens joints and ligaments to prepare for birth.

Your baby at week 31 is the size of a Coconut, measuring about 11.2 in (28.5 cm) and weighing roughly 3.0 lb (1.35 kg). Every kick, roll, and hiccup is a sign that your baby is growing strong. Soon you'll hold them in your arms.

Your Baby's Development This Week

Your baby is the size of a coconut at 31 weeks. All five senses are now fully functional, and the pupils can react to light shining through your belly. The key milestone this week is that the baby can process information from all five senses. the pupils react to light. the digestive system is fully functional.

The third trimester is about preparation — your baby is practicing breathing, sucking, and swallowing for life outside the womb. Each week of this stage significantly improves their chances of a healthy start. The countdown to meeting your baby has begun.

This week's voice theme

Five senses, one purpose — getting to know you.

Imagine hearing this every morning — a voice note from your baby that evolves week by week.

Hear your baby's voice →

Frequently Asked Questions

Can the baby see light in the womb?

Yes, the pupils can now react to light. Bright light shone on your belly may cause the baby to turn away.

Is it normal to have Braxton Hicks every day?

Yes, Braxton Hicks can occur daily in the third trimester. They should be irregular and not progressively stronger.