Nutrition and hydration
Childbirth is an energy-demanding process that requires adequate energy and hydration. The actual energy demands for labour have been estimated to be between 2.9 and 4.2 MJ per hour. Without adequate energy intake, body stores of glycogen and adipose tissue will be used to sustain energy requirements. As the period of fasting increases, ketones begin to appear in the blood. It is largely accepted that some amount of ketosis during childbirth is normal. However, as ketones begin to spill into the urine, the body becomes depleted of sodium and potassium, resulting in dehydration, which may lead to maternal or fetal acidosis. It is important, therefore, to ensure adequate nutrition and hydration to prevent such large changes in acid/base balance. It is well documented that eating in labour increases gastric volume, thereby increasing the risk of pulmonary aspiration; however, fasting in labour does not always guarantee decreased gastric contents. Isotonic fluids and foods that enhance gastric emptying may be suited for early labour.
Pairman S, Pincombe J, Thorogood C, Tracy S. (2006). Midwifery preparation for practice. Australia: Elsevier