15 Weeks Pregnant
Reviewed by Safi Allah Khan
Medically reviewed by: Safi Allah Khan · Written by the Momi team · Last updated 20 October 2026
Quick answer: At 15 weeks pregnant, your baby is about the size of an apple, about 10 cm (4 in) long. You're in the second trimester, in month 4, with 25 weeks to go until your due date. This week's milestone: bones hardening. Symptoms vary from person to person.
| Week 15 at a glance | |
|---|---|
| Trimester | Second |
| Month | 4 |
| Weeks to due date | 25 |
| Baby's size | About the size of an apple |
| Length | About 10 cm (4 in) |
| Weight | About 70 g (2.5 oz) |
| This week | Bones hardening |
Sizes are typical averages. Before about 20 weeks, length is measured crown to rump; after that, head to heel.
Your baby at 15 weeks
Your baby is about the size of an apple and weighs about 70 g (2.5 oz). The skin is very thin, and the baby is moving the arms and legs a lot, even though you probably can't feel it yet.
Your body at 15 weeks pregnant
You might notice a stuffy nose or bleeding gums. Both are common in pregnancy because of hormones and extra blood flow.
Things to do this week
- Book a dental check-up if you are due one.
- Use a soft toothbrush if your gums bleed.
- Plan your anatomy scan for 18 to 22 weeks.
When to call your doctor or midwife
Contact your care team straight away if:
- you have bleeding or fluid leaking from your vagina
- you have severe belly pain that doesn't go away
- you have a fever of 100.4°F (38°C) or higher
- you have a headache that won't go away or gets worse
- you have regular, painful tightenings
If something feels wrong, trust that feeling and call. In an emergency, call your local emergency number.
Track week 15 in Momi
Log your weight in Momi if your provider asked you to keep an eye on it. Momi follows your pregnancy week by week with your baby's size and development, and keeps your diary, bump photos, appointments, kick counts and contractions in one place.
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Keep reading
← 14 weeks pregnant · All weeks · 16 weeks pregnant →
Sources
- ACOG: Changes During Pregnancy (infographic)
- NHS: Your baby's movements
- NHS: Antenatal care and appointments
- CDC: Urgent Maternal Warning Signs
Medical disclaimer: Momi and this website provide general information, not medical advice. Always talk to your doctor or midwife; in an emergency call your local emergency number.
FAQ
How big is a baby at 15 weeks pregnant?
On average, a baby at 15 weeks is about the size of an apple: about 10 cm (4 in), about 70 g (2.5 oz). These are typical averages, and healthy babies vary.
How many months is 15 weeks pregnant?
15 weeks pregnant is in the fourth month of pregnancy and the second trimester. Months don't divide evenly into 40 weeks, so different sources may label the month slightly differently.
What should I do at 15 weeks pregnant?
Book a dental check-up if you are due one. Use a soft toothbrush if your gums bleed.
Related guides
Track this in Momi
Momi is a free pregnancy tracker app for iPhone and Android that follows pregnancy week by week, estimates the due date, and keeps a pregnancy journal, weight log, kick counter and contraction timer in one place.
