31 Weeks Pregnant

31 weeks pregnant: months, baby development and movement

At 31 weeks pregnant, you are in the third trimester and often described as about 7 months pregnant. This week follows 30 weeks pregnant, and the next page is 32 weeks pregnant.

Your baby may be about 39 cm long and weigh around 1.6 kg, though individual growth varies. The skin is becoming smoother as fat builds under it, and the body looks more proportionate.

The digestive system, lungs and nervous system continue maturing. The skull bones remain flexible, which helps during birth, and the soft spots on the head close gradually after birth.

Your body at 31 weeks pregnant

Baby movements can feel strong enough to disturb your sleep. Strong movement is usually reassuring, but what matters most is your baby's usual pattern. Contact your maternity team if movements slow down, stop, or feel clearly different.

Breathlessness can happen because the growing uterus puts pressure upward, especially before the baby moves lower later in pregnancy. Slower digestion and constipation are also common as hormones and less space in the abdomen affect the bowel.

Occasional Braxton Hicks contractions can happen, but call your clinician or maternity unit if contractions become regular, painful, increasingly strong, or come with bleeding, fluid leaking, pelvic pressure or back pain. This is especially important if you have had a previous preterm birth.

What to do this week

• Write or refine your birth plan, focusing on preferences that matter most to you.
• Practise breathing, relaxation or positioning techniques from antenatal classes.
• Ask your provider how they want you to monitor baby movements and when to call.
• Support digestion with fluids, fibre-rich foods and gentle movement.
• Use the pregnancy calculator for date estimates, but follow the due date confirmed by your clinician.

Frequently asked questions about 31 weeks pregnant