Normal pregnancy lasts 40 weeks. Most premature children are born between the 32nd and 37th week of pregnancy, but some arrive between 22 and 25 weeks. Several factors influence the presence and severity of the consequences: the number of pregnancy weeks completed at birth, whether certain complications occur, steroid use, and birth weight.
Child born between 33 and 36 weeks. The lungs are not fully developed, and the baby has trouble staying warm. He is able or almost able to feed alone. Swallowing, breathing, and latching on to the breast are difficult, and the baby tires easily. The baby is two to five times more at risk for developmental problems than a full-term baby.
Child born between 29 and 32 weeks. Breathing is less controlled and frequently interrupted. The baby often requires oxygen and must stay in an incubator, since he cannot control his body temperature well. Initially fed by a small tube inserted through the nostril or mouth to the stomach, which requires less effort than nursing and swallowing. A saline solution may also be administered to ensure that baby receives the calories and elements essential to growth. The risk of long-term consequences is 50 to 80 times higher for very premature babies than for full-term babies.
Child born before the 28th week of pregnancy. The extreme preemie cannot breath or feed on his own, and is thus connected to a respirator and an intravenous feed. He also receives several medications, has many health problems and is at greater risk for in-hospital complications. If born between the 22nd and 25th weeks, he is at the limit of viability and can suffer severe consequences.