Third trimester · 3 weeks to go
| Fact | Week 37 |
|---|---|
| Days of pregnancy | 253–259 since LMP |
| Gestational age span | 36w0d to 36w6d |
| Trimester | Third trimester (weeks 28–40) |
| Pregnancy month | Month 3 (weeks 9–13) |
| Average length | 19.1 in (crown to heel) |
| Average weight | 6.30 lb |
| Size comparison | a bunch of kale |
| Weeks remaining | 3 (40-week due date) |
Week 37 is early term: babies born now do well, though the brain and lungs still have finishing weeks. The baby practices all the skills needed outside: sucking, swallowing, grasping, blinking.
The baby's hand coordination is now strong enough to grasp. The circulatory system and lungs make their final preparations for the first breath. Antibodies transfer across the placenta at an increasing rate.
Gestationally, week 37 means you are 36 weeks and 0 to 6 days pregnant, day 253 to day 259 counted from the first day of your last period. This is week 10 of the third trimester (weeks 28–40). Appointments are weekly from week 36 until delivery. Week 39 brings full term. From here the baby gains roughly half a pound a week on average, which is why the third trimester feels measurably heavier by the day. Every number on this page is an average across pregnancies; your own scan dates and your baby's measurements are what actually describe your week 37.
Watch for the mucus plug and bloody show. If your water breaks, note the time and call; fluid, not mucus, is the call-to-action.
Weeks of pregnancy don't map cleanly to calendar months, but the common division puts week 37 falls in month 3 of pregnancy (weeks 9–13). Week 37 is part of the third trimester, which runs from week 28 to birth. Gestationally, week 37 means you are 36 weeks and 0 to 6 days pregnant.
At week 37 the baby averages 19.1 in long and weighs about 6.30 lb, roughly the size of a bunch of kale. Sizes come from fetal growth charts (crown-to-heel length from week 20), and normal variation week to week is wide; your ultrasound measurements always outrank a chart.