Your Pregnancy Week by Week: Weeks 17-20

Week 17

Baby: Your baby now has doubled in weight in the last two weeks. Fat begins to form, helping your baby's heat production and metabolism. The lungs are beginning to exhale amniotic fluid, and the circulatory and urinary systems are working. Hair on the head, eyebrows, and eyelashes is filling in.

Mom-to-be: You're showing more now, with a typical weight gain of 5-10 pounds. You may also be noticing that your appetite has grown.

Tip of the Week: To avoid feeling dizzy or faint, change positions slowly, especially when you move from a lying down position to sitting or from a sitting position to standing. If you feel lightheaded, sit down and lower your head, or lie down for a moment.

Week 18

Baby: Your baby's rapid growth spurt is tapering off, but reflexes are kicking in. The baby can yawn, stretch, and make facial expressions, even frown. Taste buds are beginning to develop and can distinguish sweet from bitter. The baby will suck if its lips are stroked, and it can swallow and even get the hiccups. The retinas have become sensitive to light, so if a bright light is shined on your abdomen, baby will probably move to shield its eyes.

Mom-to-be: Your uterus, about the size of a cantaloupe, can probably be felt just below your navel. You're most likely feeling the baby move by now. A mid-pregnancy ultrasound may be performed between now and 22 weeks to assess the baby's growth and development and to verify the due date. If the baby is in the right position, the ultrasound may show whether it's a boy or a girl. Your heart has to work 40% to 50% harder now to support your pregnancy.

Tip of the Week: Could your partner go with you for the ultrasound? It's a chance to catch the first glimpse of your baby together.

Week 19

Baby: Your baby's skin is developing and transparent, appearing red because blood vessels are visible through it. A creamy white protective coating, called vernix, begins to develop on the baby's skin.

Mom-to-be: As your baby continues to grow, you may be feeling some mid-pregnancy aches and pains by now -- lower abdominal achiness, dizziness, heartburn, constipation, leg cramps, mild swelling of ankles and feet, and a backache. Dilated blood vessels might cause tiny, temporary red marks (called spider nevi) on your face, shoulders, and arms.

Tip of the Week: Take care of yourself! Try not to get overtired while the baby is growing so quickly.

Week 20

Baby: Your baby can hear sounds by now -- your voice, heart, and your stomach growling, as well as sounds outside your body. The baby will cover its ears with its hands if a loud sound is made near you, and it may even become startled and "jump." The baby is moving often, too -- twisting, turning, wiggling, punching and kicking.

Mom-to-be: Congratulations! You're near the midpoint of your pregnancy. Your uterus is just about even with your navel. Your waistline has pretty much disappeared. Bladder infections are more likely, because certain muscles in the urinary tract relax. Your breathing will deepen and you may sweat more than usual because your thyroid gland is more active.

Tip of the Week: Backache? Watch your posture. Sit with a footstool or use an ergonomic chair, avoid standing for too long, sleep with a small pillow under your side at the waist, and lift things with your legs instead of your back.

What's Happening Inside You?

Hair is beginning to grow on your baby's head, and lanugo, a soft fine hair, covers his or her shoulders, back, and temples. This hair protects your baby and is usually shed at the end of the baby's first week of life.

Your baby's skin is covered with a whitish coating called vernix caseosa. This "cheesy" substance, thought to protect baby's skin from long exposure to the amniotic fluid, is shed just before birth.

You may begin to feel your baby move because he or she is developing muscles and exercising them. That movement is called quickening.