At 13 weeks pregnant, your infant is about 2.91 inches (7.4cm) and weighs around 0.81 ounce (23gm) - This is about the same weight as 4 quarters.
If you could peek in again you may spot your baby as he begins to practice inhaling and exhaling movements
Eyes and ears continue to move and develop at week 13 of your pregnancy
Baby's neck is getting longer, and the chin no longer is resting on his chest
Her hands are becoming more functional - Your baby may find it comforting to start playing with her fist.
After 13 weeks of pregnancy, all nourishment is received from the placenta
On your next doctor visit you should be able to hear heartbeat with a Doppler by now - (Don't worry though if you can't, the heartbeat can be confirmed through U/S). Your baby's heartbeat is much more rapid than your own and may remind you of the race towards birth that he is running!