Lungs are close to fully mature
Baby this week: about 44.8 cm — head to heel · about 2.1 kg
≈ 44.8 cm — about the size of a cantaloupe
Illustration enlarged for clarity — the amber marker shows true relative size
Your baby this week
- The lungs are nearly mature, with just a bit more development left
- The waxy vernix coating and downy lanugo hair start to shed
- The central nervous system and lungs continue fine-tuning ahead of birth
- The fetus has settled into a fairly consistent sleep-wake pattern
Your body this week
- Frequent, shorter sleep stretches at night are common as comfort becomes harder to find
- Some notice their belly button flattening or even popping out
This week's tip: This is a reasonable week to start packing a hospital bag, so it's ready well before your due date.
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.