In the United States and most developed countries, during the previous 4 or 5 decades, the preterm birth (PTB) rate has either remained stable or, more commonly, risen slowly.1 This rise has occurred despite increasing knowledge of risk factors and mechanisms and the introduction of numerous public health and medical interventions designed to reduce PTB. Preterm birth has 3 obstetrical antecedents: (1) spontaneous preterm labor and (2) spontaneous membrane rupture, which taken together result in spontaneous PTB, and (3) the decision of the physician to induce labor or perform a cesarean delivery because of fetal distress or maternal illness, resulting in an indicated PTB. The article by Haas et al2 would have been strengthened if the risk factors for preterm delivery had been studied with respect to these specific types of PTB.
Goldenberg RL, Culhane JF. Prepregnancy Health Status and the Risk of Preterm Delivery. Arch Pediatr Adolesc Med. 2005;159(1):89-90. doi:10.1001/archpedi.159.1.89