Objective To study the effects of oral carbohydrate ingestion on clinical outcome and on maternal and fetal metabolism.
Design Prospective, double-blind, randomised study.
Setting Leyenburg Hospital, The Hague, The Netherlands.
Population Two hundred and two nulliparous women.
Methods In labour, at 8 to 10 cm of cervical dilatation, the women were asked to drink a solution containing either 25 g carbohydrates or placebo. In a subgroup of 28 women, metabolic parameters were measured.
Main outcome measures Number of instrumental deliveries, fetal and maternal glucose, free fatty acids, lactate, pH, Pco2, base excess/deficit and β-hydroxybutyrate.
Results Drinking a carbohydrate-enriched solution just before starting the second stage of labour did not reduce instrumental delivery rate (RR 1.1, 95% CI 0.9–1.3). Caesarean section rate was lower in the carbohydrate group, but the difference did not reach statistical significance (1%vs 7%, RR 0.2, 95% CI 0.02–1.2). In the carbohydrate group, maternal free fatty acids decreased and the lactate increased. In the umbilical cord there was a positive venous–arterial lactate difference in the carbohydrate group and a negative one in the placebo group, but the differences in pH and base deficit were comparable.
Conclusion Intake of carbohydrates just before the second stage does not reduce instrumental delivery rate. The venous–arterial difference in the umbilical cord suggested lactate transport to the fetal circulation but did not result in fetal acidaemia.