Week 10

The embryo reaches a developmental milestone at the end of this week--it has achieved its basic structural form, and will be known as a fetus (Latin for "offspring") from now until it reaches full term. Because the fetus is still curled up in a snug position in the uterus, it's hard to measure an exact length including the legs. For this reason, health professionals use the crown-to-rump measurement, or the distance from the top of the head to the buttocks. Your baby's crown-to-rump length is now about 1 1/4 inches, and she weighs less than half an ounce.