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 prophylactic betamimetic therapy during the second stage of labour on perinatal outcome.
Search strategy: The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched. Date of last search: February 1999.
Selection criteria: Randomised trials comparing prophylactic intravenous betamimetic therapy during the second stage of labour with placebo or no treatment in uncomplicated pregnancies.
Data collection and analysis: The reviewers assessed trial quality and extracted data.
Main results: One study involving 100 women was included. Compared to placebo, prophylactic betamimetic therapy was associated with an increase in forceps deliveries (relative risk 1.83, 95% confidence interval 1.02 to 3. 29). There were no clear effects on postpartum haemorrhage, neonatal irritability, feeding slowness, umbilical arterial pH values or Apgar scores at 2 minutes.
Reviewer's conclusions: There is no evidence to support the prophylactic use of betamimetics during the second stage of labour.