Identifying women with preterm labor who ultimately
will give birth preterm is difficult. Approximately 30%
of preterm labor spontaneously resolves (26) and 50%
of patients hospitalized for preterm labor actually give
birth at term (27–29). Interventions to reduce the likelihood
of delivery should be reserved for women with
preterm labor at a gestational age at which a delay in
delivery will provide benefit to the newborn. Because
tocolytic therapy generally is effective for up to 48 hours
(30), only women with fetuses that would benefit from
a 48-hour delay in delivery should receive tocolytic
treatment.