A Little About Baby at Week 18

TheBump.com
Baby's now the size of a sweet potato!
Baby's become amazingly mobile (compared to you, at least), passing the hours yawning, hiccupping, rolling, twisting, kicking, punching, sucking, and swallowing. And baby is finally big enough that you'll soon be able to feel her movements.

BabyCenter.com
Head to rump, your baby is about 5 1/2 inches long (about the length of a bell pepper) and he weighs almost 7 ounces. He's busy flexing his arms and legs — movements that you'll start noticing more and more in the weeks ahead. His blood vessels are visible through his thin skin, and his ears are now in their final position, although they're still standing out from his head a bit. A protective covering of myelin is beginning to form around his nerves, a process that will continue for a year after he's born. If you're having a girl, her uterus and fallopian tubes are formed and in place. If you're having a boy, his genitals are noticeable now, but he may hide them from you during an ultrasound.

Baby2See.com

• You are 18 weeks pregnant. (fetal age 16 weeks)
  
• The fetus is now 6 inches long and weighs 7 ounces.
  
• The fetus measures about 15cm and weighs almost 200 grams.
  
• They can hear sounds and may be startled by loud noises.
  
• Recognizable active and rest periods.
  
• The skin is building a protective wax layer (vernix).
  

Vernix (a white cheese like protective material) forms on baby's skin with the lanugo, a soft lightly pigmented hair covering the body and limbs, both help to protect your baby's skin during the months in water. Your baby may hear your heart beating, your stomach rumbling or blood moving through the umbilical cord. He or she may even be startled by loud noises.

Tiny air sacs called alveoli begin to form in lungs and the vocal chords are formed. Baby goes through the motions of crying but without air doesn't make a sound; yet.

Your baby may have the same awake and sleep patterns of a newborn. Baby will have a favorite position for sleep and recognizable active and rest periods.

Your baby measures about 6 inches (15cm) crown to rump and weighs about 7 ounces (200gm).

Pregnancy Today
How is your baby growing?
Your baby's main job this week is to plump out. She's now about the right size to fit into your palm, and is developing a layer of fat under her skin. This will help keep her warm after the birth, but for now, your amniotic fluid does the job for her, keeping her at a constant 99.6 degrees Fahrenheit (37.5 Celsius), slightly warmer than your own body temperature.

Your baby is now recognizably either a boy or a girl, with a visible penis and testes or a fledgling uterus and vagina. If you're having a girl, she already has around two million eggs in her ovaries. Connections are constantly forming in her brain, meaning she has more control over her limbs, fingers and toes. Her blood circulation is well established, and the umbilical cord is becoming thicker and longer to transport oxygen and nutrients into her body. Your baby and the placenta are almost the same size.