31 weeks pregnant
Third trimester about 7 months
At 31 weeks pregnant, your baby is about the size of a coconut.
Baby this week
About 41cm. The baby is practicing breathing, blinking, and sucking. Its immune system is strengthening via antibodies from the mother. The baby is running out of room to move.
Did you know? The baby receives a massive transfer of antibodies from the mother during the third trimester — these protect the newborn during the first months of life before their own immune system matures.
What she may be feeling
- Pelvic pressure and discomfort
- Braxton Hicks
- Colostrum leaking possible
- Back pain
- Swelling
- Fatigue
- Frequent urination
- Difficulty sleeping
Tips for her this week
- Colostrum (early breast milk) may start leaking from your breasts — this is normal.
- Sleep on your left side to optimize blood flow to the baby.
- Braxton Hicks will increase — time them to practice distinguishing from real contractions.
- Rest, rest, rest — your body is doing an enormous amount of work.
For partners
- She may be feeling anxious, excited, or completely overwhelmed — all normal at this stage.
- Be an active listener. Don't try to fix everything — sometimes just being present is the point.
- Ensure the nursery is completely ready and functional.
- Research and enroll in a newborn care class if you haven't.
Partner to-do list
- Attend a newborn care class together
- Ensure nursery is fully ready
- Research and watch swaddling tutorials
- Make sure your phone is always charged — labor can start anytime now
This week together
- Attend a newborn care class
- Finalize visitor policy post-birth
- Ensure postpartum supply list is complete
- Discuss breastfeeding support plan
When to call your doctor or midwife
Contact your care provider right away, or call emergency services, if she has:
- Decreased fetal movement
- Signs of preeclampsia
- Regular contractions before 37 weeks
- Leaking fluid
- Heavy bleeding
Trusted guidance: NHS: Pregnancy · NHS: Pregnancy complications · ACOG: Pregnancy · Pregnancy Info: Your pregnancy
Common questions
How big is the baby at 31 weeks?
At 31 weeks pregnant, your baby is about the size of a coconut. About 41cm.
How many months is 31 weeks pregnant?
31 weeks pregnant is about 7 months, in the third trimester.
What can partners do at 31 weeks?
She may be feeling anxious, excited, or completely overwhelmed — all normal at this stage. Be an active listener. Don't try to fix everything — sometimes just being present is the point.