We compared the metabolic effects of allowing women isotonic "sport drinks" rather than water to drink during labor. The effect of these drinks on gastric residual volume was also evaluated. Sixty women in early labor (cervical dilation <5 cm) were randomized to receive either isotonic sport drinks or water only. Plasma beta-hydroxybutyrate, nonesterified fatty acids, and glucose were measured in early labor and at the end of the first stage of labor. Residual gastric volume was assessed within 45 min of delivery by use of an ultrasound scanner. The incidence and volume of vomiting was recorded. At the end of the first stage of labor, plasma beta-hydroxybutyrate (P = 0.000) and nonesterified fatty acids (P = 0.000) had increased and plasma glucose (P = 0.007) had decreased significantly in the Water-Only group. Gastric antral cross-sectional area after delivery was similar in the two groups. The incidence of vomiting and the volume vomited during labor and within the hour of delivery were also similar. There was no difference between the groups in any maternal or neonatal outcome of labor. In conclusion, isotonic drinks reduce maternal ketosis in labor without increasing gastric volume.
Implications: Solid foods may endanger a woman's life if consumed during labor. Isotonic sport fluids were evaluated as a nutritional alternative. Results demonstrate that mothers who have not received parenteral opioids can safely drink isotonic drinks in active labor.