Prematurity continues to be a major public health problem and, despite advances in antenatal care, prematurity rates continue to rise in the United States. Preterm and low-birth-weight (LBW) rates increased in 2006 to 12.8% and 8.3%, respectively. The very low birth weight (VLBW) (<1500 g) rate rose to 1.46% (62,283 of 4,265,996 births in 2006). In addition, the birth rate for women aged 40–44 years rose 3% to 9.4 per 1,000 between 2005 and 2006 (Martin et al. 2008). A component of the increase in the preterm birth rate remains attributed to older maternal childbearing, multiple births, and increasing rates of assisted reproductive technology (Heck et al. 1997). The increase in the number of multiple births is a concern because of the associated increased risk of death, preterm birth, low birth weight, and long-term adverse neurodevelopmental outcomes. Major therapeutic advances in perinatal and neonatal care in the past 20 years, including surfactant therapy, antenatal steroids for both pulmonary maturation and central nervous system protection, improved ventilation techniques, and parenteral nutritional support have resulted in a significant improvement in survival of extremely low-birth-weight infants (ELBW) (<1000 g) (National Institutes of Health [NIH] 1995; El-Metwally, Vohr, and Tucker 2000; Fanaroff, Hack, and Walsh 2003; Fanaroff et al. 2007; Hintz et al. 2005a; Hintz et al. 2005b). These infants have increased complex neonatal medical morbidities affecting all organ systems including lungs, gastrointestinal tract, kidneys, and brain, and increased growth, neurological, developmental, and behavioral morbidities both in the neonatal intensive care unit (NICU) and after discharge (Blakely et al. 2005; Ehrenkranz, 2000; Ehrenkranz et al. 2005; Laptook et al. 2005; Shankaran et al. 2004; Schmidt et al. 2003; Vohr et al. 2003; Vohr et al. 2004;Vohr et al. 2005; Walsh et al. 2005). Predicting the survival and neurodevelopmental outcomes of preterm infants becomes a challenge since outcomes are dependent on a combination of biologic factors including gender, gestational age, birth weight, singleton versus multiple, neonatal morbidities, neonatal interventions, and post-discharge environment.
“Wait and See” approach to antenatal steroids in threatened preterm birth
