# 31 Weeks Pregnant: Baby Size, Symptoms & What to Expect | Clever Mum > 31 weeks pregnant — your baby is the size of a coconut. What's developing, what you might feel, and what to focus on this week. * [ Home ](/) * › [ Pregnancy ](/pregnancy/) * › [ Week by week ](/pregnancy/week/) * › Week 31 Third trimester # 31 weeks pregnant Your baby is about the size of a coconut [ CP ](/authors/parenting-desk/) By [ Clever Mum Parenting ](/authors/parenting-desk/) · Parenting guides Published 11 July 2026 Quick answer — What happens at 31 weeks pregnant? At 31 weeks pregnant, your baby is about the size of a coconut, roughly 41.1cm and around 1500g. The baby can now process information from all five senses. Who should skip this Skip this page if you need personal medical advice — it is general NHS-aligned information, not a substitute for your midwife. If your baby's movements slow or change, call your maternity unit, not a website. ## How big is the baby at 31 weeks pregnant? At 31 weeks pregnant, your baby is about the size of a coconut, roughly 41.1cm and around 1500g. The baby can now process information from all five senses. They're practising breathing movements and may settle into a head-down position, though many still turn. These are typical averages — your midwife's measurements are the ones that matter for your pregnancy. ## What might you feel at 31 weeks? Most people at 31 weeks notice some mix of the symptoms below — and plenty notice none of them. You may leak more colostrum and feel Braxton Hicks more often. Backache and pelvic pressure increase. Fatigue and "nesting" urges can both appear. None of this is a diagnosis; contact your midwife if something worries you. ### Common symptoms this week * More colostrum leaks * Pelvic pressure * Nesting urges * Fatigue Symptom lists are typical, never exhaustive — and having none of them is normal too. ## What should you do at 31 weeks pregnant? The useful job this week is practical, not medical. Wash and sort baby clothes and bedding in non-bio detergent, and set up the car seat so you can practise fitting it before the birth. Pair it with the NHS week-by-week guide if you want a second description of the same stage. ### Week 31 checklist * Attend the 31-week appointment if it's your first baby * Wash baby clothes and bedding in non-bio detergent * Fit the car seat once and practise — don't leave it until week 39 ## What else is useful at 31 weeks? Use the week page for size and symptoms; use the guides below for the decisions that actually sit in this window — pay, packing, car seats, labour signs. * [Due date calculator](/tools/due-date-calculator/) * [Trimester to-do list](/pregnancy/pregnancy-to-do-list-by-trimester/) * [Maternity leave and pay](/pregnancy/maternity-leave-and-pay-uk/) * [Best infant car seats](/best/best-car-seats-uk/) * [Hospital bag checklist](/pregnancy/hospital-bag-checklist-uk/) ## 31 weeks pregnant: common questions Should I buy newborn or 0–3 month clothes? Mostly 0–3 months, with a few newborn-size items as backup — newborn sizing runs small and many babies outgrow it in a fortnight, if they fit it at all. Five to seven sleepsuits and vests per size covers the reality of several changes a day. How big is my baby at 31 weeks pregnant? At 31 weeks, your baby is approximately the size of a coconut, about 41.1cm and around 1500g. These are approximate averages — every baby grows at its own pace. What's happening at 31 weeks pregnant? The baby can now process information from all five senses. They're practising breathing movements and may settle into a head-down position, though many still turn. For you: you may leak more colostrum and feel braxton hicks more often. backache and pelvic pressure increase. fatigue and "nesting" urges can both appear. Which trimester is 31 weeks? 31 weeks pregnant is in the third trimester. The first trimester runs to the end of week 12, the second from weeks 13 to 26, and the third from week 27 to birth. ## Sources & further reading * [ You and your baby at 4 to 40 weeks pregnant ](https://www.nhs.uk/pregnancy/week-by-week/) — NHS * [ Your baby's movements ](https://www.nhs.uk/pregnancy/keeping-well/your-babys-movements/) — NHS [← 30 weeks](/pregnancy/week/30/) [All weeks](/pregnancy/week/) [32 weeks →](/pregnancy/week/32/) This is general information, not medical advice — every pregnancy is different. For anything that worries you, and for all your antenatal care, speak to your midwife or GP. If your baby's movements ever slow down or change, contact your maternity unit immediately, day or night. Reviewed August 2026. ## Week 31 at a glance Trimester Third trimester Baby size coconut Approx length ~41.1cm Approx weight ~1500g Weeks to go 9 (to 40) Work out your dates Not sure how many weeks you are? Our [due date calculator](/tools/due-date-calculator/) maps your weeks and trimester dates from your last period.