Week 4 Four weeks from the start of your last period, a positive test shows you're pregnant.
Week 5 Measured from crown of head to rump, your baby is about 0.4 inch long—the size of a green pea.
Week 8 The baby is about 1 inch long—the size of a large olive. His features are already distinctly human.
Week 10 Your doctor will probably want to see you between eight and 10 weeks for your first appointment. That's when you'll get to view the heartbeat via ultrasound.
Week 11 Your baby is about 3 inches long—the size of a large goldfish. Most of his organs are already functioning.
Week 13 You made it through the first trimester! Good news: If you had morning sickness, it will likely be ending now.
Week 15 You're beginning to show, and your baby is starting to do things like frown, swallow and clasp his hands.
Week 16 Your baby is about 5 inches long—the size of a peach. Around this time, his taste buds start to develop.
Week 19 At this point, your baby may begin to turn, stretch, suck his thumb and hear sounds. Also, his sex organs are becoming visible.
Week 22 Between 16 and 22 weeks, you'll start to feel your baby move. The movements are usually fluttery at first but soon progress to full-fledged kicks.
Week 24 Your baby starts to respond to outside noises and practice breathing motions.
Week 28 Now about 15 inches long (the size of a football), your baby is viable if born early.
Week 29 Your baby's protective lanugo (body hair) starts to disappear, his legs curl up into the fetal position, and he begins hiccupping.
Week 32 Your baby is about 15 to 17 inches long—the size of a small cat. He may turn head-down now.
Week 34 The lungs are still developing, but the other organs are almost fully mature.
Week 35 It's time to choose a pediatrician. She'll need to check your baby while still in the hospital.
Week 36 Decide if you'll bank your baby's cord blood. If so, choose a facility.
Week 38 The baby is primarily packing on fat in preparation for life on the outside.