Behind the Baby Count
One sure biological factor is volume overload from multiple-birth pregnancies, something that's been on the rise with the increased use of fertility treatments. In fact, our steadily declining infant mortality rate stalled and took a slight blip upward in 2003 possibly because of that. But there are other triggers of early labor like placental deterioration, inflammation or infection, or mixed-up hormonal signals. There is also evidence that specific genes may make some families (or maybe ethnic groups) prone to spontaneous preterm births.
Recall the young son of a president, Patrick Bouvier Kennedy, who was born six weeks premature and died at Harvard Medical School's Children's Hospital Boston in 1963. He was unable to breathe because his immature lungs could not yet produce the substance surfactant, which keeps the lung's air sacs open. As a student there a few years later, I remember how doctors spoke of Patrick as a classic case of hyaline membrane disease, which was killing preterm infants of the day. Until some 20 years later when a drug form of surfactant appeared-and survival of infants like Patrick increased to over 80 percent. Now that's a score card to remember.