Guzman E R, Conley M, Stewart R, Ivan J, Pitter M, Kappy K
Department of Obstetrics and Gynecology, Newark Beth Israel Medical Center, New Jersey.
Obstet Gynecol. 1993 Sep;82(3):375-9.
To compare the effects of maternally administered phenytoin and magnesium sulfate on the fetal heart rate (FHR) using computer analysis.
Thirty-six nonlaboring preeclamptic women between 27-41 weeks' gestation were treated with either phenytoin or magnesium sulfate in a nonrandomized fashion. All fetuses were deemed to be well by traditional electronic-biophysical criteria. One-hour FHR recordings were analyzed by computer analysis before treatment. No other medications were administered. Tracings recorded 1 hour after drug administration were analyzed. Therapeutic serum levels were achieved in both groups before FHR tracings were reevaluated. Statistical analysis used paired Student t test, with significance set at P < or = .05.
There were no differences in birth weight, gestational age, Apgar scores, or computer-analyzed FHR characteristics between the groups before treatment. Magnesium sulfate reduced significantly the frequency of accelerations of ten and 15 beats per minute; caused a 62% reduction in reactivity, defined as accelerations of 15 beats per minute in 20 minutes of FHR tracing (but no change in reactivity with accelerations of ten beats per minute); and reduced short- and long-term variability. Phenytoin reduced short-term variability only.
Phenytoin does not confound the computer analysis of FHR tracings and may offer some advantage over magnesium sulfate when used for prophylaxis against eclampsia.
