4 - Interventions to prevent prematurity

Summary

Introduction

In the United States, 10% of all pregnancies end prematurely, that is, before 37 weeks’ gestational age. Prematurity is responsible for a large majority of neonatal mortality among normally formed infants and as much as 50% of birth-attributable major neurologic disability, including cerebral palsy (McCormick, 1985). In addition, due to organ system immaturity, preterm infants are subject to a host of acute medical morbidities. Much of this mortality and morbidity is concentrated in the very lowest birth weight (< 1500 gm) or early gestational age infants (< 32 weeks), who represent between 10 and 20% of preterm births (only 1–2% of all births) (Copper et al., 1993; Robertson et al., 1992). In contrast, preterm birth at relatively more advanced gestational ages (35 and 36 weeks) represents 50% or more of all preterm births and, on an individual basis, infrequently results in severe morbidity or death.

This chapter builds upon the previous chapter by reviewing the evidence on interventions currently practiced to prevent prematurity or improve its outcomes. As the discussions of these interventions – prenatal care, risk scoring, behavior change interventions, early identification of preterm labor, nutrition interventions, tocolytic drugs, bed rest, maternal hydration, cerclage for incompetent cervix, progestins, antibiotic treatment for infections, and interventions for premature rupture of the membranes – will show, few prevent preterm delivery. However, the development of effective antibiotic treatment strategies for bacterial vaginosis has great potential for improving some important outcomes associated with early spontaneous preterm birth in high-risk women.