Eyebrows and hair on your baby’s scalp are starting to appear this week. If your baby is going to have dark hair, the hair follicles may begin making the pigment that will give the hair its dark color. Your baby’s eyes and ears now have a baby-like appearance, and the ears have almost reached their final position, although they’re still riding a little low on the head. Your baby’s skin is adding hair follicles and accessory glands, but it is still very thin. The bone and marrow that make up baby s skeletal system continue to develop this week. Muscle development is continuing, too. By the end of the week 15 of pregnancy, your baby will be able to make a fist.
Your heart has enlarged to cope with the increased amount of blood circulating in your body and the baby's need for oxygen, and has increased its output by 20 per cent. You will be feeling more energetic than before and now is a good time to have a holiday before the birth.
When 15 weeks pregnant, the fetal skeleton of the baby is developing and its legs are now longer than its arms. The hair on its head is becoming thicker and it has eyelashes as well as eyebrows. The baby can probably hear now and the amniotic fluid makes an excellent sound conductor, so it will be able to hear your stomach rumbling and your heart beating as well as the sound of your voice. The baby is 4 inches (10 cm) long and now weighs around 2.5 ounces (71 grams)