Treatment of acute intrapartum fetal distress by beta 2-sympathomimetics.

Patients with a diagnosis of severe intrapartum fetal distress by fetal heart rate and capillary blood pH monitoring received beta 2-sympathomimetics to inhibit uterine contractions (tocolysis) while the obstetric team was preparing to deliver the fetus. Fetal heart rate and acidosis significantly improved after tocolysis; these fetuses were subsequently delivered in very good metabolic and clinical condition. The favorable effect of tocolysis on fetal homeostasis is attributed to the suppression of the ischemic effect of contractions on the placental circulation. The few fetuses having an extremely compromised placental function showed no improvement in heart rate or acidosis with tocolysis and were immediately delivered. Considering the mild side effects observed, the lack of maternal complications, and the remarkable perinatal outcome obtained, we recommend using tocolysis before delivering distressed fetuses.