Your fetus is continuing to grow and develop rapidly. They are around 9-10 cm (3.5-4.0 inches) long (crown to rump) and weigh about 50 grams (1.75 ounces). Legs are growing faster than the arms, contributing to more proportionate growth. Ultra-fine hair (lanugo) is growing all over the fetus's body, including the eyebrows and upper lip. This lanugo protects the delicate skin from the amniotic fluid and usually disappears just before or after birth. Underneath the lanugo is a fine layer of skin through which the blood vessels can be seen. The mouth continues to develop; the fetus may even be sucking its thumb at this point. Facial movements are becoming more regular. Meconium, a substance made up of bile, mucus, and other cellular debris, is present in the intestines. The fetus begins to inhale and exhale amniotic fluid, practicing breathing motions. The crown-to-rump length is around 11-13cm, and the weight is around 70g.