Rapid brain development continues as the fetus processes information
Baby this week: about 41.3 cm — head to heel · about 1.5 kg
≈ 41.3 cm — about the size of a coconut
Illustration enlarged for clarity — the amber marker shows true relative size
Your baby this week
- The brain is developing at a rapid pace, forming new connections constantly
- The fetus can turn its head from side to side
- Many babies gain roughly 200–250 g a week from this point on
- The immune system is starting to develop, aided by antibodies passed from the parent
Your body this week
- Shortness of breath and heartburn are common as the uterus pushes against the diaphragm and stomach
- Some notice colostrum, an early form of breast milk, beginning to appear
This week's tip: Eating smaller meals more often and staying upright after eating can help ease heartburn.
When to get help now
Contact your maternity unit now, even at night, if your baby is moving less than usual or the pattern has changed, you have any vaginal bleeding, fluid leaks from your vagina, you have regular or painful contractions before 37 weeks, or you have a severe headache, vision changes, pain just below the ribs or sudden swelling of the face, hands or feet. Do not wait until the next day.
Sizes and milestones are typical ranges — every pregnancy runs on its own clock. Educational content; your prenatal care team's guidance always comes first.