🤰 Third trimester
42 weeks pregnant
Your baby is about the size of a watermelon
By Emma Whitfield · Pregnancy & Baby Writer
Your baby at 42 weeks
Fewer than 1 in 10 pregnancies reach 42 weeks. The baby continues to grow and the placenta is monitored closely, because it gradually becomes less efficient past this point.
Your body at 42 weeks
By 42 weeks you'll usually have been offered induction, since the risk of complications rises slowly beyond this stage. If you decline, you'll be offered extra monitoring (CTG and scans) instead — the choice remains yours.
Common symptoms this week
- Very overdue (fewer than 1 in 10 get here)
- Daily or alternate-day monitoring
- Every tightening scrutinised
Symptom lists are typical, never exhaustive — and having none of them is normal too.
Focus this week
Talk through the induction process with your midwife so you know what to expect — pessary or gel, breaking the waters, and a hormone drip are the usual steps, in that order and only as needed.
Week 42 checklist
- Attend all monitoring appointments (CTG traces and fluid scans)
- Confirm your induction date and what to bring
- Rest — the finish line is genuinely days away
42 weeks pregnant: common questions
Is it safe to go past 42 weeks pregnant?
Risks to the baby rise slowly but measurably beyond 42 weeks as the placenta ages, which is why UK guidance recommends induction by then and close monitoring (CTG and fluid checks) for anyone who declines. Whatever you choose, it's made with your team — consent remains yours throughout.
How big is my baby at 42 weeks pregnant?
At 42 weeks, your baby is approximately the size of a watermelon, about 51.7cm and around 3700g. These are approximate averages — every baby grows at its own pace.
What's happening at 42 weeks pregnant?
Fewer than 1 in 10 pregnancies reach 42 weeks. The baby continues to grow and the placenta is monitored closely, because it gradually becomes less efficient past this point. For you: by 42 weeks you'll usually have been offered induction, since the risk of complications rises slowly beyond this stage. if you decline, you'll be offered extra monitoring (ctg and scans) instead — the choice remains yours.
Which trimester is 42 weeks?
42 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
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 July 2026.