Preterm birth: an increasing public health concern

health concern Three million infants die before their first birthday as the result of being born prematurely (Ahman and Zupan, 2007). According to global statistics, the greatest cause of infant mortality in the USA is preterm birth, which is the birth of a child after less than 37 weeks of completed gestation, rather than the typical 40 weeks (Committee on Understanding Premature Birth and Assuring Healthy Outcomes Board on Health Sciences Policy, 2006). In addition to a high risk for neonatal death, preterm infants have an increased incidence of chronic complications including intellectual disability, respiratory illness, and vision and hearing impairment. These pathologies make prematurity a leading cause of disability adjusted life-years (DALYs), as they arise at the earliest stages of life (Murray and Lopez, 1997). In 2007, 12.7% of all births in the USA were preterm, an increase of approximately 20% since 1990 (Heron et al., 2010). The rate of preterm birth in black women in the USA remains nearly twofold greater than for white women with otherwise-similar demographic characteristics (Martin et al., 2009). This difference represents one of the largest racial disparities in national health. Preterm birth is a complex multifactorial process associated with diverse pathogenetic mechanisms including infection, maternal stress and changes in obstetric practices, such as indications for induced delivery and artificial reproductive technologies. Birth, or parturition, which is the process of giving birth, involves a complex switch of the uterus from a static and docile environment to the generator of contractile force sufficient to expel a baby. Little is known about the factors that regulate this dynamic switch. Approximately one half of all preterm births are idiopathic (Muglia and Katz, 2010) with no recognized precipitating factor. Increased insight into the etiology of spontaneous idiopathic preterm birth is necessary to effectively model and address this rising public health concern.