Pregnant in week 17
In week 17 your baby is the size of a pear. It is now starting to build the fat layers that will keep it warm after birth, and the skeleton slowly changes from soft cartilage to firmer bone.
Your baby in week 17
Your baby measures around 13 centimetres and weighs about 140 grams. The body begins to lay down the brown fat that later helps regulate body temperature after birth.
The skeleton, which has so far been soft cartilage, now gradually hardens into bone. The umbilical cord becomes stronger and thicker, and your baby practises swallowing and sucking – important training for life outside.
The sweat glands begin to form, and the heart is now regulated by the brain rather than beating entirely on its own. Your baby moves a lot and often changes position.
Your body and symptoms in week 17
Your centre of gravity shifts forward as the bump grows, and it can be felt in your balance and back. Good shoes and conscious posture make a big difference.
Many now experience the first clear movements from their baby. Blood volume has risen considerably, which can cause a feeling of warmth, flushed cheeks and occasional dizziness if you stand up quickly.
The skin on your belly and breasts stretches, and some get itching or the first stretch marks. How many you get is hereditary, but a moisturiser soothes the tightness.
Good advice for week 17
Choose sensible footwear
With a changed centre of gravity your balance becomes less steady. Flat, stable footwear prevents falls and relieves the back.
Get up slowly
Dizziness is often because blood briefly pools in the legs. Get up calmly, and sit down if things start to spin.
Moisturise your belly
Cream doesn't prevent stretch marks, which are hereditary, but soothes the itching and tightness the growing skin can cause.
Sleep on your side
Start getting used to sleeping on your side. Which side does not matter. A pillow between your knees and under your belly makes it more comfortable.
Relevant with us in week 17
This is what we can offer you at this point in your pregnancy.
Frequently asked questions in week 17
Why do I get dizzy?
The increased blood volume and widened blood vessels can cause brief drops in blood pressure, especially when you stand up. Eat and drink regularly, and rise calmly.
Can I still train my core?
Avoid classic sit-ups from the second trimester. Gentle exercises for the deep abdominal and pelvic floor muscles are good, however – ask a physiotherapist if unsure.
When should I take leave from work?
It depends on your health, your job and your wellbeing. Talk to your doctor or midwife about what fits your situation – there is no fixed rule.
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Read on in week 17
Gender scan – when can you see the sex? Everything you need to know (2026)
Feeling life – when and how do you feel the first fetal movements?
