In week 33, your baby is now about 12 inches long from head to rump (19 and a half inches from head to toe) and weighs about 4and a half pounds. His body weight has increased by more than 10 percent in just one week.
He looks more and more like a full-term baby, but his lungs still aren't fully mature. He also acts differently from a newborn. For one thing, he often sticks out his tongue, something newborns rarely do. Three-dimensional ultrasounds even catch babies of this age smiling, something newborns usually don't do until they're about 3 months old.
Your baby is old enough to survive outside of the womb, but you don't want to rush him. Even if you do everything you can to prevent premature labor, you still have to watch for signs of trouble. One alarming possibility is having your water break, also known as premature rupture of the membranes. If your water breaks, you may experience a gush of amniotic fluid from your vagina that slows to a trickle. Or you may notice a trickle of cloudy white or straw-colored fluid. In some cases, only a laboratory test can tell whether you're leaking amniotic fluid or urine.
If you think your water may have broken, check with your healthcare provider immediately. You aren't necessarily going into labor, but your baby may be in trouble without prompt treatment. If tests show that you're leaking amniotic fluid, you may need to be hospitalized for a couple of weeks until your doctor induces labor.
If your baby seems to be in distress, you may need to be induced immediately. He'll be a little ahead of schedule, but he should be ready to handle life on the outside with a little help from his friends in the hospital newborn nursery. Normally, a baby born at this point will need to spend a couple of weeks in the hospital to make sure he's breathing well and feeding and growing properly.
Campbell, Stuart, MD. Watch Me Grow. St. Martins Griffin.
Monash University. Fetal and Neonatal Lung Development Laboratory. http://www.med.monash.edu.au/physiology/research/fetalandneonatal/FNLD/
Children's Hospital and Regional Medical Center. Lung Hypoplasia. http://www.pediatricweb.com/seattle/article.asp?ArticleID=829&ArticleType=9
University of North Carolina Center for Maternal and Infant Health. Preterm premature rupture of membranes. http://www.mombaby.org/level2/pprom.html
Merck Manual. Premature Rupture of Membranes. http://www.merck.com/mrkshared/mmanual/section18/chapter253/253c.jsp