15 Weeks Pregnant: Your Baby’s Development Hair today. By the end of the week, your little one's scalp hair pattern will be established for life. Some hair might begin to sprout, although it's usually not evident for a few more weeks. Of course, this is no guarantee that your baby will be born with a full head of hair; some babies stay bald until several months after birth. Ultrafine, soft hair called lanugo is also appearing over your little one's entire body. This downy hair protects the delicate skin from the amniotic fluid and usually disappears just before or after birth. Thin-skinned. Underneath that lanugo is a fine layer of skin through which you can see blood vessels, which are already transporting blood. Mouth development continues — your little one may even be sucking on a thumb right now — and facial movements are a regular occurrence. 15 Weeks Pregnant: Your Symptoms Power surge. Many women report feeling energized at this point in the pregnancy. If you're one of the fortunate ones with that extra oomph, enjoy it! Take a walk, plant some flowers, or start planning the baby's room. Not so swell. Now is also the time when you may start to notice some mild swelling, called edema, in your extremities. Swollen feet and ankles are the most common, but you may also experience some swelling in your hands, causing the rings on your fingers to fit more tightly. Edema occurs when fluid is pushed from the bloodstream into the soft tissues. As with many pregnancy complaints, it's caused by the increased blood circulating through your body and the pressure of your growing uterus on the pelvic veins. Prevention strategies. The best way to prevent edema is through mild exercise: a walk, a swim, a yoga class. Also, rest frequently with your feet elevated and be sure to drink plenty of water every day. If you experience anything more than a little fullness in your feet or hands, or if you also have puffiness in your face or eyes, contact your healthcare provider.