30 WEEKS PREGNANT
The fetus can track light and dark through closed eyelids
Baby this week: about 40 cm — head to heel · about 1.3 kg
≈ 40 cm — about the size of a large butternut squash
Illustration enlarged for clarity — the amber marker shows true relative size
Your baby this week
- The fetus can now distinguish light from dark, even with eyes closed
- Amniotic fluid levels are near their peak, giving plenty of room to move
- Bone marrow has fully taken over red blood cell production
- Brain tissue continues to develop grooves and folds rapidly
Your body this week
- Fatigue can return as sleep becomes harder to find due to size and frequent bathroom trips
- Some people start noticing more frequent Braxton Hicks contractions
This week's tip: If you haven't already, this is a common time to start thinking about a birth plan and discussing preferences with your provider.
Want the bigger picture — organ development, nutrition, scans and warning signs for this stage? See month 7: The world gets louder.
Sizes and milestones are typical ranges — every pregnancy runs on its own clock. Educational content; your prenatal care team's guidance always comes first.