Week 17 Pregnancy

Second Trimester

Last reviewed: July 2026

17 weeks pregnant at a glance

You are in the second trimester.
Your baby is roughly the size of a pear.
Routine care.
Every pregnancy is different, so don't worry if your experience varies slightly.

You are 17 weeks pregnant and in your second trimester. Your baby is about the size of a pear. This week's key development: Growing Strong. NHS note: Routine care.

This page is for general pregnancy planning and date guidance only. It is not medical advice, diagnosis, or treatment. Pregnancy dates are estimates and can change after a scan or advice from your midwife, GP, or maternity team. Always speak to a qualified healthcare professional if you have symptoms, concerns, or questions about your pregnancy.

Week 16

Week 18

Baby's Development

Your baby is about the size of a pear.

Growing Strong — Fat is beginning to accumulate under your baby's skin, which will help regulate their temperature after birth. Their skeleton continues to harden, and the umbilical cord is growing thicker and stronger — the lifeline between you two.

Pear

Approx. 12cm

Your Symptoms

Increased sweating
Itchy skin on your belly
Stretch marks may appear

Every pregnancy is different. You may experience all, some, or none of these symptoms — and that's completely normal. If anything concerns you, speak to your midwife.

NHS Appointments

Routine care. Your next big milestone is the 20-week anomaly scan.

Practical Advice for Week 17

Nutrition

Continue vitamin D and eat a varied, balanced diet.
Omega-3 fatty acids support your baby's brain development — include oily fish or supplements.
If heartburn is starting, avoid spicy or fatty foods close to bedtime.
Magnesium-rich foods (bananas, dark chocolate, almonds) may help with leg cramps.

Exercise

Continue moderate exercise — your body will tell you what feels right.
Gentle stretching helps with the itchy, stretching skin on your belly.
Swimming relieves pressure on your joints and back.
Avoid lying flat on your back during exercise — use an incline instead.

Wellbeing

Itchy skin on your belly is normal as it stretches — moisturise liberally.
Stretch marks may appear — they're a badge of honour, and they fade over time.
Increased sweating is caused by higher metabolism and blood flow.
Use a pregnancy-safe moisturiser or oil on your bump — coconut oil or bio-oil are popular.

Preparation

Your next big milestone is the 20-week anomaly scan — check it's booked.
Start looking at pushchairs and car seats — research takes time.
Consider whether you want to find out your baby's sex at the 20-week scan.
If you haven't told your employer yet, you must do so by 15 weeks before your due date.

Tip of the Week

Use a moisturiser or oil on your growing bump to help soothe itchy, stretching skin.

Frequently Asked Questions for Week 17

How many months is 17 weeks pregnant?

At 17 weeks pregnant, you are roughly 3 months pregnant. Remember that pregnancy is typically measured in weeks rather than months for clinical accuracy.

What size is the baby at 17 weeks?

At 17 weeks, your baby is roughly the size of a pear (about 12cm). Fat is beginning to accumulate under your baby's skin, which will help regulate their temperature after birth. Their skeleton continues to harden, and the umbilical cord is growing thicker and stronger

What are the common symptoms at 17 weeks pregnant?

Common symptoms at this stage include increased sweating, itchy skin on your belly, stretch marks may appear. Remember that every pregnancy is unique, and it's normal to experience different symptoms.

Is 17 weeks in the second trimester?

Yes, 17 weeks falls within the second trimester.

Are there any NHS appointments at 17 weeks?

Routine care. Your next big milestone is the 20-week anomaly scan.