Second trimester
Week 13 of Pregnancy
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About the size of a peach
2.9 in · 7.4 cm · 0.8 oz · 23 g (crown to rump)
Your baby this week
- Welcome to the second trimester — vocal cords are forming.
- Unique fingerprints are being etched onto tiny fingertips.
- The baby can swallow small amounts of amniotic fluid.
What you may be feeling
- A visible bump for many
- More steady energy
- Breast tenderness easing
Gentle tips for this week
- With provider approval, this is a great time to start gentle exercise like walking, swimming or prenatal yoga.
- Enjoy the energy — plan projects and errands now while they are easiest.
Common question for week 13
Which week does the second trimester start?
Most sources count weeks 13 or 14 as the start of the second trimester. BabyAwaits uses weeks 13-27, the most common convention in the United States.
Every pregnancy is different. Sizes are averages, symptoms vary widely, and none of this replaces the guidance of your own provider.