When it's late in your pregnancy and you're counting the days until your due date, it's a good idea to remember that a due date is really only an approximation. Only 5% of babies are actually born on their due date; 95% are born in the 2 weeks before or the 2 weeks after the due date.

One of the greatest wonders of birth is the almost instantaneous transition the baby makes to breathing air after 9 months of living in the womb, breathing no air whatsoever. Although pulmonary vessels are in place and the heart is pumping, blood circulating through the fetus bypasses the lungs altogether. Then, when baby takes her first breath, blood pressure in the lungs starts to drop lower than systemic blood pressure, and blood begins to flow into the lungs. At the same time, the shunts in the heart through which fetal blood flows start to close, changing the pattern of blood circulation to that of an adult. The respiratory control center in the brain stem signals the diaphragm muscle to contract, the rib cage expands, and the lungs fill like sails in a gale. These simultaneous changes are coordinated as deftly and precisely as a symphony orchestra. Babies are marvels!