Your baby now weighs about 425-500 grams (15 ounces - 1.1 pounds) and measures around 20 cm (7.9 inches) crown to rump. Their hearing is well established, and they can make out a distorted version of your voice, your heartbeat, and your stomach rumblings. In addition to improved hearing, their lungs are preparing to breathe, although they'll be breathing amniotic fluid, not air, until birth. Advances in neonatal care mean that if born prematurely at this stage, your baby has a significantly improved chance of survival (around 85%) with appropriate medical intervention. Their hair is beginning to grow – eyelashes, eyebrows, and hair on their head. The amniotic fluid surrounding your baby provides the perfect environment for growth. This salty fluid keeps them warm, protects them from infection, and allows them to exercise their developing muscles through buoyant movements. Your baby looks like a tiny, thin newborn and measures 9 to 10 inches in total length. Their heartbeat is getting stronger, and they are starting to make antibodies, strengthening their immune system.