Some preterm babies are fed through an umbilical artery catheter, a tube placed through the navel, or by an intravenous placed through a vein in the baby's head or scalp. This IV contains a solution with the nutrients the baby needs for survival. More mature preemies may be fed by formula, or even breast milk. Breast milk is preferred, if the baby has developed good enough sucking skills, another skill developed late in pregnancy, and also if the baby's body is functional enough to tolerate the milk. Some advantages of breast milk over formula are that breast milk can improve growth, provide antibodies against infection, stimulate faster nerve growth, and help regulate heartbeat and breathing patterns through sucking, making the flow of oxygen more even and efficient.
Heart problems are another common problem among prematurely born babies.
The most common problem is that blood might circulate through the body, but without passage through the lungs. This happens while the baby is in the fetus, and continues until about the thirty-sixth week when the lungs are almost fully functional. Recently, a drug has been developed that can be used as a substitute to the old method of surgery that was used to combat this problem in most cases. The causes for premature birth is generally an underdeveloped placenta. One thing that is known to have an affect on this is cigarette smoke, which lowers the oxygen supply to the placenta.