Myocardial Infarction during Nifedipine Therapy for Preterm Labor

To the Editor: Recent studies have suggested that nifedipine is a safer, more effective treatment for preterm labor than the sympathomimetic agents routinely in use.1,2 On the basis of these promising results, calcium-channel antagonists are increasingly prescribed for tocolysis. On the other hand, a case–control study of hypertensive patients found that patients who were taking calcium-channel antagonists had an increased risk of myocardial infarction,3 and a meta-analysis found a dose-dependent association between the use of nifedipine and the risk of death.4 These data, however, are not necessarily applicable to pregnant women who are being treated for preterm labor. We . . .