Second trimester · 24 weeks to go
| Fact | Week 16 |
|---|---|
| Days of pregnancy | 106–112 since LMP |
| Gestational age span | 15w0d to 15w6d |
| Trimester | Second trimester (weeks 14–27) |
| Pregnancy month | Month 2 (weeks 5–8) |
| Average length | 4.6 in (crown to rump) |
| Average weight | 3.5 oz |
| Size comparison | an avocado |
| Weeks remaining | 24 (40-week due date) |
Week 16 is hearing week: tiny bones in the ears are in place and the baby can start registering your voice. Facial muscles now work well enough for squints and grimaces, and the heart pumps around 25 quarts of fluid a day.
The scalp pattern is forming, though hair isn't visible yet. Toes reach an inch long, and the uterus you grew is now the size of a papaya. Movement is frequent but still featherlight.
Gestationally, week 16 means you are 15 weeks and 0 to 6 days pregnant, day 106 to day 112 counted from the first day of your last period. This is week 3 of the second trimester (weeks 14–27). Prenatal appointments run about every four weeks in this stretch. Week 20 brings the anatomy scan window (weeks 18–22). Across this trimester the baby more than triples in weight, so expect your bump, your appetite, and eventually your waddle to keep pace with the calendar. 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 16.
Talk and read aloud; low-frequency voices carry best into the womb. Begin gentle back stretches to stay ahead of the backache.
Weeks of pregnancy don't map cleanly to calendar months, but the common division puts week 16 falls in month 2 of pregnancy (weeks 5–8). Week 16 is part of the second trimester, which runs from week 14 to week 27. Gestationally, week 16 means you are 15 weeks and 0 to 6 days pregnant.
At week 16 the baby averages 4.6 in long and weighs about 3.5 oz, roughly the size of an avocado. Sizes come from fetal growth charts (crown-rump length before week 20), and normal variation week to week is wide; your ultrasound measurements always outrank a chart.