Tocolytics for suspected intrapartum fetal distress

Abstract

BACKGROUND: Prophylactic tocolysis with betamimetics and other agents has become widespread as a treatment for fetal distress. Uterine relaxation may improve placental blood flow and therefore fetal oxygenation. However there may also be adverse maternal cardiovascular effects. OBJECTIVES: The objective of this review was to assess the effects of tocolytic therapy for suspected fetal distress on fetal, maternal and perinatal outcomes. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. Date of last search: February 1999. SELECTION CRITERIA: Randomised trials comparing tocolytic therapy with no treatment or treatment with another tocolytic agent for suspected fetal distress. DATA COLLECTION AND ANALYSIS: Two reviewers assessed trial quality and extracted data. MAIN RESULTS: Three studies were included. Compared with no treatment, there were fewer failed improvements in fetal heart rate abnormalities with tocolytic therapy (relative risk 0.26, 95% 0.13 to 0.53). Betamimetic therapy compared with magnesium sulphate showed a non-significant trend towards reduced uterine activity (relative risk 0.07, 95% confidence interval 0.00 to 1.10). REVIEWER'S CONCLUSIONS: Betamimetic therapy appears to be able to reduce the number of fetal heart rate abnormalities and perhaps reduce uterine activity. However there is not enough evidence based on clinically important outcomes to evaluate the use of betamimetics for suspected fetal distress.