🤰 Second trimester
13 weeks pregnant
Your baby is about the size of a lemon
By Emma Whitfield · Pregnancy & Baby Writer
Your baby at 13 weeks
Welcome to the second trimester. The baby now has tiny fingerprints, and vocal cords are forming. The head is becoming more proportionate to the body.
Your body at 13 weeks
This is often the "golden trimester" — nausea eases, energy returns and appetite picks up. Some notice a small bump appearing, especially in second pregnancies.
Common symptoms this week
- The "golden trimester" beginning
- Returning appetite
- Visible bump in second pregnancies
Symptom lists are typical, never exhaustive — and having none of them is normal too.
Focus this week
A good week to start gentle exercise if you've paused — walking, swimming and pregnancy yoga are all recommended. Keep it comfortable, not competitive.
Week 13 checklist
- Restart gentle exercise if you paused — walking, swimming, pregnancy yoga
- Start moisturising the bump if you enjoy it (it soothes itching, though no cream prevents stretch marks)
13 weeks pregnant: common questions
When does the second trimester start?
At the start of week 13. The second trimester runs from weeks 13 to 26 and is typically the most comfortable stretch — nausea eases, energy returns, and the bump is present but not yet cumbersome.
How big is my baby at 13 weeks pregnant?
At 13 weeks, your baby is approximately the size of a lemon, about 7.4cm and around 23g. These are approximate averages — every baby grows at its own pace.
What's happening at 13 weeks pregnant?
Welcome to the second trimester. The baby now has tiny fingerprints, and vocal cords are forming. The head is becoming more proportionate to the body. For you: this is often the "golden trimester" — nausea eases, energy returns and appetite picks up. some notice a small bump appearing, especially in second pregnancies.
Which trimester is 13 weeks?
13 weeks pregnant is in the second 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.