Maternal β-Adrenergic Tocolysis and Neonatal Bilirubin Production

Neonatal Bilirubin Production after Preterm Labor Tocolysis with Nifedipine

“…First, both drugs could have no major effect on in vivo total bilirubin production. In the case of RIT, this is consistent with past results [5,6]. NIF, however, did not produce a rise in HbCO as we had expected based on findings from a previous experiment with nicardipine in rats [4], This difference between NIF and nicardipine may be due to the fact that, although the two drugs are both classified as CEB agents, they have different mechanisms of cellular action.…”

“…This observation raised the ques tion about whether a CEB given to a mother for preterm labor tocolysis could stimulate total bilirubin formation in the fetus, a side effect which could aggravate the hyperbiliru binemia already afflicting many neonates. Furthermore, Ochikubo et al [5] and Hop per et al [6] found that ritodrine (RIT), a ß2-mimetic, had no clinically important ef fect on neonatal total bilirubin formation in rats and humans. In light of these findings, one might wonder whether RIT would be the preferable tocolytic agent in terms of avoid-ß-Adrenergic drugs are commonly used for tocolysis of preterm labor.…”