A compilation of ultrasound images taken at six months and three weeks of pregnancy. Watch a 4D ultrasound of a baby’s movements during the third trimester played against a music background.
At three weeks, the developing embryo is in its blastocyte phase, and will measure only one sixth of an inch long! By six months, the fetus will be covered with fine hair known as "lanugo," and will begin to practice breathing by inhaling amniotic fluid into the lungs.
