The effect of unrestricted oral carbohydrate intake on labor progress. Eating in labour. A randomised controlled trial assessing the risks and benefits. An evaluation of isotonic "sport drinks" during labor. A comparison of the effectiveness, tolerability and safety of high and low carbohydrate diets in women with gestational diabetes.
To determine if unrestricted oral carbohydrate intake during labor reduced the incidence of dystocia in low-risk nulliparous women.
                A randomized clinical trial at a university-affiliated hospital in southeastern Ontario. Low-risk nulliparous women were randomized between 30 and 40 weeks gestation to either an intervention or usual care group.
                Women in the intervention group received, prenatally, guidelines about food and fluid intake during labor and were encouraged to eat and drink as they pleased during labor. Women in the usual care group received no prelabor information and were restricted to ice chips and water during labor in the hospital.
                The incidence of dystocia, defined as a cervical dilatation rate of less than 0.5 cm/hr for a period of 4 hrs after a cervical dilatation of 3 cm.
                Three hundred twenty-eight women were randomized to the intervention (n = 163) or usual care (n = 165) groups. Women in the intervention group reported a significantly different pattern of oral intake during early labor in the hospital (chi(2) = 40.7, p < .001). The incidence of dystocia was 36% (n = 58) in the intervention group and 44% (n = 72) in the usual care group and was not significantly different (OR = 0.71, 95% CI = 0.46, 1.11). There were no significant differences in the other secondary outcomes or in the incidence of adverse maternal or neonatal complications.
                Eating and drinking early in labor had no significant impact on the incidence of dystocia and/or adverse maternal or neonatal outcomes. The aim of this study was to determine whether permitting women in labour to eat a light diet would: (i) alter their metabolic profile, (ii) influence the outcome of labour, and (iii) increase residual gastric volume and consequent risk of pulmonary aspiration. Women were randomised to receive either a light diet (eating group, n = 48) or water only (starved group, n = 46) during labour. The light diet prevented the rise in plasma beta-hydroxybutyrate (p = 2.3 x 10(-5)) and nonesterified fatty acids (p = 9.3 x 10(-7)) seen in the starved group. Plasma glucose (p = 0.003) and insulin (p = 0.017) rose in the eating group but there was no difference in plasma lactate (p = 0.167) between the groups. There were no differences between the groups with respect to duration of first or second stage of labour, oxytocin requirements, mode of delivery, Apgar scores or umbilical artery and venous blood samples. Relative gastric volumes estimated by ultrasound measurement of gastric antral cross-sectional area were larger (p = 0.001) in the eating group. This was supported by the observation that those from this group who vomited, vomited significantly larger volumes than those in the starved group (p = 0.001). We conclude that eating in labour prevents the development of ketosis but significantly increases residual gastric volume. 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.
                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. Nutrition therapy is an integral part of the management of gestational diabetes mellitus (GDM). Most women with GDM are treated by nutritional management alone. The goal of our study was to compare low and high carbohydrate diets in their effectiveness, safety and tolerability in women with GDM.
                The study group consisted of 30 Caucasian women newly diagnosed with GDM, with a mean age of 28.7 +/- 3.7 years and pregnancy duration of 29.2 +/- 5.4 weeks. The patients were randomised into two groups: those on a low and those on a high carbohydrate diet (45% vs. 65% respectively of energy supply coming from carbohydrates). The presence of urine ketones was controlled every day. After two weeks daily glucose profiles and compliance with the recommended diets were analysed.
                Glucose concentration before implementation of the diet regimen did not differ between groups. No changes in fasting blood glucose were noticed in the group that had followed a low carbohydrate diet, although a significant decrease in glucose concentration was observed after breakfast (102 +/- 16 vs. 94 +/- 11 mg/dl), lunch (105 +/- 12 vs. 99 +/- 9 mg/dl) and dinner (112 +/- 16 vs. 103 +/- 13 mg/dl) (p < 0.05). In the high carbohydrate diet group fasting and after-breakfast glucose concentration did not change. A significant decrease in glycaemia was noticed after lunch (106 +/- 15 vs. 96 +/- 7 mg/dl) and dinner (107 +/- 12 vs. 97 +/- 7 mg/dl) (p < 0.05). Ketonuria was not observed in either group. Obstetrical outcomes did not differ between groups.
                Both high and low carbohydrate diets are effective and safe. A diet with carbohydrate limitation should be recommended to women who experience the highest glycaemia levels after breakfast.
Since the evidence shows no benefits or harms, there is no justification for the restriction of fluids and food in labour for women at low risk of complications. No studies looked specifically at women at increased risk of complications, hence there is no evidence to support restrictions in this group of women. Conflicting evidence on carbohydrate solutions means further studies are needed and it is critical in any future studies to assess women's views.