If they don't wait until after week twelve, many women at least wait to share the news about their pregnancies until after they first hear the heartbeat via Doppler. This is because the risk of miscarriage drops dramatically once the placenta is fully developed. If your doctor doesn't find the fetal heartbeat during your visit, that doesn't mean there's anything wrong with your baby -- the fetus may have been turned away from the Doppler or nestled too far back in the uterus.
You could start showing any day now ... or it may be a while before that bump is visible. Every woman is different, so don't worry if your waistline is bigger or smaller than a friend's or relative's when she was nine weeks along. As long as your OB says that you and the baby are healthy, that's what matters.
If you lose weight due to vomiting or nausea, you might be worried that your baby isn't getting enough nutrition. But remember, the fetus is just an inch long -- it doesn't need much. Your baby will take what it needs. If you can't keep down anything but rice cakes and apple juice for days on end, don't worry: You'll soon be able to eat more normally ... sort of. Crazy cravings, here we come!