Premature babies born between 33 and 34 weeks are called moderately preterm babies. Weighing between 4 and 5 pounds at birth and measuring almost 20 inches long, these babies are getting much closer to the size of a baby born at term. Although they are getting bigger, 33 and 34 weekers are still immature, and may need to stay in the NICU for several weeks.
Premature babies are almost fully developed by 33 and 34 weeks. Their bones are fully formed, their fingernails come to the ends of their fingertips, and in boys, the testicles are descending into the scrotum. However, the respiratory system doesn't finish developing until the last weeks of pregnancy, and antibodies are only starting to pass from mom to baby.
At 33 and 34 weeks, most premature babies will have fairly short NICU stays with only a few complications. They may need help breathing for a short time, but learning to eat may take the longest. The suck-swallow-breathe reflex is not well coordinated, and these babies may not be strong enough to take in enough nourishment to grow and gain weight.