31 Weeks Pregnant

You’re in the third trimester and your baby is about the size of a pineapple. Here’s how your baby is developing, what you might feel, and the check-ups to plan this week.

Reviewed against ACOG & WHO guidance Updated 25 September 2026
Baby is about the size of
A pineapple (ananas)
Length ~41.1 cmWeight ~1.5 kgTrimester 3Month 7

Sizes are averages; from week 20 length is measured head to heel. Not sure which week you’re in? Calculate it.

Your baby at 31 weeks

All five senses are working. The baby can turn the head from side to side and is gaining weight quickly.

Your body at 31 weeks

Braxton Hicks contractions may be more frequent. Some women leak a little colostrum (early milk) from the breasts.

Common symptoms this week

  • Braxton Hicks
  • Leaking colostrum
  • Shortness of breath

Tips & to-do list

  • Learn the difference: Braxton Hicks are irregular and ease with rest; true labour contractions become regular, stronger and closer.
  • Learn about breastfeeding – including feeding within the first hour after birth.
  • Use nursing pads if you leak colostrum.

Check-ups and tests around this week

  • Tdap/Td vaccination as advised (27–36 weeks)
  • Growth scan and Doppler if advised (28–32 weeks)
  • Antenatal visits about every 2 weeks

Week 31 at a glance

At 31 weeks
TrimesterThird trimester
Pregnancy monthMonth 7 of 9
Weeks to due date9 weeks
Days pregnant217–223 days
Progress78% of 40 weeks

When to call your doctor

Contact your doctor or go to hospital straight away if you notice:

  • Reduced or changed baby movements
  • Waters breaking or any bleeding
  • Severe headache, vision changes, pain under the ribs
  • Regular painful contractions before 37 weeks
  • Severe itching of palms and soles

Questions about 31 weeks pregnant

How many months is 31 weeks pregnant?

31 weeks pregnant falls in month 7 of pregnancy, in the third trimester. For medical purposes, weeks and days are more precise than months.

How big is my baby at 31 weeks?

At 31 weeks your baby is about the size of a pineapple (ananas) – roughly ~41.1 cm long and weighing about ~1.5 kg.

Is it normal to have no symptoms at 31 weeks?

Yes. Every pregnancy is different, and symptoms come and go. Feeling well is not a sign that something is wrong. If you have concerns, or notice any warning signs listed on this page, contact your doctor.

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Medical disclaimer: The results and information on this page are estimates for general education only. They are not a diagnosis and do not replace advice from your gynaecologist, obstetrician or midwife. If you have pain, bleeding, reduced baby movements or feel unwell, contact your doctor or call 108 immediately. Read the full disclaimer.

Written by the Pregnancy Calculator editorial team. Based on published obstetric guidance (ACOG, WHO, MoHFW India, FOGSI). Last updated . How we create content.