Week 17 of 40 · second trimester

Week 17 of pregnancy

Week 17 sits in the middle stretch of pregnancy, the second trimester.

Sources checked October 30, 2026

A pregnant woman with one hand resting on her bump
Week 17
23 weeks to go
About the size of
a pear
The Log menu during pregnancy: Symptom, Appointment, Sleep, Mood and Contractions
The Log menu during pregnancy.
Illustration of a pear, the average size of a baby at 17 weeks
Your baby this week

About the size of a pear

SizeAbout a pear
Length4.7 in (12 cm), measured from head to bottom (crown to rump) [1]
Weight6.3 oz (179 g) [3]
TrimesterSecond trimester
Weeks to goAbout 23 to your due date

These are averages. Every baby grows at their own pace.

What's developing

The baby can move their eyes, react to loud noises, and open and close their mouth. Fingernails are starting to grow. [1]

What you might notice

Your waist starts to vanish as your womb moves up and out of your pelvis, so you look more obviously pregnant. [1]

Everyone's pregnancy is different. If something worries you, call your midwife or doctor.

A tip for this week

Aches and pains should be manageable. If they're not, talk to your doctor or midwife. [1]

Questions you could bring to your next appointment

  • When is my mid-pregnancy scan?
  • Will I be offered a glucose test?
  • Is there anything I should change about exercise or work?

Questions

When will I feel the baby move?

The NHS says between 16 and 24 weeks. In a first pregnancy you might not feel movements until after 20 weeks.

What if I haven't felt the baby move by 24 weeks?

Tell your midwife or doctor. They'll check your baby's heartbeat and movements.

Is my baby exactly this size?

Probably not exactly. The length is the average the NHS gives for this week, and the weight is the middle value (50th percentile) of the WHO fetal growth charts. Your scan results are the ones that count.

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