7 Week Embryo Size At 7 weeks of pregnancy, your baby is growing at an incredible pace, with major changes happening every day. The embryo measures about 0.4 inches (10 mm) long and has a curved, tadpole-like shape. The brain is developing rapidly, dividing into different regions that will later control movement, senses, and thinking. The heart is beating steadily and pumping blood through a growing network of blood vessels. Tiny limb buds are becoming more defined, with early hands and feet sta