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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Preterm Labor and Preterm Premature Rupture of Membranes
Sponsored by The Indian Health Service Clinical Support Center
10. Corticosteriods
Corticosteroid therapy has been an important step forward in perinatal medicine and extensive data support its benefit. Steroids act by promoting the transcription of the enzymes necessary for production of the cellular products needed for extrauterine existence, most prominent of which is pulmonary surfactant. The Oxford Database of Perinatal Trials convincingly demonstrate that the incidence of IRDS is halved (OR 0.49, CI 0.41-0.60), and that this effect is most marked in infants under 32 weeks (OR 0.38, CI 0.24-0.60), and applies as well to pregnancies delivered because of PPROM (OR 0.55, CI 0.40-0.75), as well as idiopathic preterm labor. The effect is maximum from 24 hours up to 7 days after administration (OR 0.31, CI 0.23-0.42), but is also seen more than 7 days after dosing (OR 0.69, CI 0.50-0.94). Male and female fetuses will benefit equally. Repeated courses of steroids are not recommended because of the association of repeated dosing, especially more than three courses, with lower birth weight, reduced head circumference, as well as the later development of childhood attention deficit disorder.
Besides its pulmonary effects, antenatal corticosteroid administration is also associated with a reduced incidence of neonatal death (OR 0.59, CI 0.47-0.75), intraventricular hemorrhage (OR 0.45, CI 0.21-0.97), necrotizing enterocolitis (OR 0.37, CI 0.17-0.69), and a trend toward fewer later neurologic abnormalities (OR 0.61, CI 0.34-0.1.08). Their use is not associated with a higher risk of infection, either maternal (OR 1.11, CI 0.81-1.51), or neonatal (OR 0.83, CI 0.54-1.26). This lack of an association with infection was similarly seen in patients with PPROM. Clearly, the utility of tocolysis is the opportunity it presents to “get the steroids on board”! Betamethasone and dexamethasone are not inactivated by placental 11-beta-hydroxylase, and are thus the only corticosteroids that cross the placenta to the fetus. There seems to be a slight survival advantage of betamethasone over dexamethasone , making betamethasone the preferred agent. The dose of betamethasone is 12 mg IM q24 hours x 2 doses. The dexamethasone dose is 6 mg IM q12 h x 4 doses. Because of issues with the manufacturer, the pharmacy doesn't always have betamethasone available, so use what you have. Of all the things you do for your patient with PTL, steroids are probably the most significant!
