Baby now measures about 4.3 to 4.6 inches from crown to rump and weighs about 2.8 ounces. Fingernails are well-formed and the fine hair, called lanugo, continues to grow on the head. Arms and legs are moving, the nervous system is functioning and muscles are responding to stimulation from your baby’s brain. You may be able to hear the baby’s heartbeat in the doctor’s office. Your uterus has grown significantly by now and weighs about 8.75 ounces.

–Web MD Weekly Newsletter