Week 13 of pregnancy

13 Weeks Pregnant

Second trimester

Baby size

About the size of a lemon

7.4 cm

What's developing

You're at the end of the first trimester. Vocal cords are forming and the intestines have moved into the abdomen.

Common symptoms this week

  • More energy
  • Fewer bathroom trips
  • Visible veins
  • Higher libido for some

This is an estimate for information only — only about 1 in 20 babies arrive on their due date. Always confirm dates with your midwife or doctor.

How big is a baby at 13 weeks?

Baby growth chart

Typical fetal length and weight from week 8 to week 40.

Weeks 8–40

Length

cm

Week 13: 7.4 cm

0153045816243240crown–heel →

Weight

grams

Week 13: 23 g

0500g1.5kg3kg816243240

Typical averages based on Hadlock / ACOG references. Weeks 8–20 use crown–rump length; weeks 21–40 switch to crown–heel — that's the small jump you'll see mid-chart. Real babies vary — your ultrasound is the reliable number for you.

Frequently asked questions

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