Identifying the Causes
About 25 percent of premature births result from early induction of labor or cesarean delivery due to pregnancy complications, such as placental problems, or health issues in the mother, such as uncontrollable high blood pressure. In most of these cases, early delivery is the safest route. However, a recent March of Dimes study suggests that increasing rates of induced labor and cesarean deliveries are contributing to the rising number of late preterm births. Clearly, women should aim for continuing a pregnancy to term when this option is safe for both mother and baby.
Most premature births result from spontaneous preterm labor; in nearly 40 percent of these cases, doctors cannot determine the cause. Studies suggest, however, that the body's natural response to certain bacterial infections, such as uterine infections, may play a role. These infections may lead to inflammation and the release of hormone-like substances that may trigger labor. Unfortunately, women with uterine infections often have no symptoms, making it difficult to diagnose and treat them in time. Other infections to watch for include urinary-tract infections and periodontal (gum) disease, though how or why they relate to preterm labor is still not completely understood. Urinary-tract infections are easily diagnosed and treated with early and routine prenatal care, as is gum disease with regular visits to the dentist.
Certain chronic health conditions (such as high blood pressure, diabetes, or blood-clotting disorders), pregnancy complications (such as vaginal bleeding), and lifestyle factors (such as smoking, drinking alcohol, or taking street drugs) can also play a role in preterm births.