At week 17 your baby is starting to build fat, which will help keep them warm after birth.
Your baby this week
- Fat
- The first fat stores are forming under the skin.
- Bones
- Soft cartilage keeps turning into bone throughout the skeleton.
- Sweat glands
- They're starting to develop.
What you might notice
- A bigger appetite. Regular meals and snacks help your energy.
- Round ligament pain, sharp twinges low in your belly when you move quickly.
- Vivid dreams and trouble getting comfortable at night.
- Feeling clumsy as your centre of gravity changes.
Call your midwife, doctor or maternity unit today if
- You have bleeding, or fluid leaking from your vagina
- You have tummy pain that doesn't go away, or regular tightenings
- You're being sick so often you can't keep fluids down
- You have a fever, or it burns or stings when you pee
Any time of day or night. You will never be a nuisance for calling.
Coming up
Your anatomy scan.
A good time to start thinking about birth classes, which often book up early.
Questions to bring to your next appointment
- What position is best for sleeping now?
- Where can I find birth classes, and when should I book?
- Is the pain I sometimes feel low in my belly normal?
For your partner
Look up birth classes together and pick one you'll both go to. Booking early is easier.
NUGA follows you week by week
Enter your due date once and NUGA knows you're at week 17. The day before each appointment, it gathers what you've noted and the questions to bring.
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This page draws on public guidance from:
General information, not medical advice. Every pregnancy is different, and your midwife or doctor knows yours. Last updated October 2026.