Restricting oral intake during labor, often called “nothing by mouth” (NPO), is a long-standing hospital tradition that causes confusion and discomfort. This rule, which typically means no food and only limited clear fluids, can be frustrating during the physically demanding and prolonged event of childbirth. We will examine the medical reasons for this restriction, why it was applied so strictly for decades, and how modern obstetrics and anesthesiology are changing the guidelines.
The Core Physiological Danger: Aspiration Risk
The primary medical concern justifying the restriction of food during labor is the risk of pulmonary aspiration, which occurs if stomach contents are inhaled into the lungs. Labor significantly slows down the digestive process, meaning the stomach retains food and fluid for much longer than usual. This delayed gastric emptying is compounded by the stress and pain of contractions, and sometimes by the use of certain pain medications.
The danger escalates if an emergency requires the mother to undergo a procedure under general anesthesia, such as an unplanned cesarean delivery. General anesthesia suppresses the body’s protective reflexes, including the ability to cough or gag. This makes it easier for stomach contents to be regurgitated and aspirated into the airway. If highly acidic gastric contents enter the lungs, it can cause a severe chemical burn and inflammation known as aspiration pneumonitis, or Mendelson’s syndrome.
Mendelson’s syndrome is a serious complication characterized by symptoms like cyanosis, fever, and breathing difficulty, and historically carried a high risk of maternal death. While aspiration is rare today, the consequence can be fatal, which is why precautions remain in place. Any patient requiring general anesthesia is treated as though they have a “full stomach,” regardless of their recent intake.
Why the Fasting Rule Became So Strict
The strict “nothing by mouth” policy originated in the mid-20th century, following the work of physician Curtis Mendelson in the 1940s. Mendelson’s research highlighted the severe dangers of aspirating stomach contents, especially for women receiving general anesthesia for delivery. At that time, general anesthesia was much more common for pain management and complications, placing a large number of laboring patients at high risk.
Due to the high mortality rate associated with Mendelson’s syndrome, a blanket policy of fasting was adopted globally as a necessary safety measure. This policy was designed to protect the mother by minimizing the volume and acidity of potential aspirate in case emergency general anesthesia was needed. The practice became a deeply ingrained standard of care, even as medical techniques advanced.
Modern Recommendations: When Light Eating Is Permitted
The strict fasting rule has been relaxed in many settings, largely due to the widespread adoption of regional anesthesia, particularly the epidural. Regional anesthesia numbs the lower body but allows the mother to remain awake, significantly reducing the need for general anesthesia in obstetrics. This shift has lowered the overall risk of aspiration for most laboring patients.
Major medical bodies, such as the American Society of Anesthesiologists (ASA) and the American College of Obstetricians and Gynecologists (ACOG), now recommend that uncomplicated, low-risk laboring patients consume clear liquids. Clear liquids include water, fruit juices without pulp, clear tea, black coffee, and sports drinks. However, the consumption of solid food is still advised against during active labor for all patients, as there is insufficient evidence to support its safety.
The individual patient’s risk profile determines the exact limitations. Patients with additional risk factors, such as morbid obesity, preeclampsia, or poorly controlled diabetes, or those with a high likelihood of needing an operative delivery, may have stricter limitations. The availability of effective pain relief like an epidural has also been shown to improve gastric emptying, further supporting the less restrictive approach.
Managing Hydration and Energy During Labor
Since solid food is still avoided, patients need alternative strategies to maintain energy during labor. Intravenous (IV) fluids are often administered to maintain hydration and provide a steady supply of glucose, which fuels the high energy demands of labor. This method bypasses the digestive system entirely, eliminating the aspiration risk associated with a full stomach.
Even when solid food is restricted, oral intake of ice chips, popsicles, and hard candies is often permitted, as they provide comfort and moisture without posing a significant aspiration risk. The laboring patient should communicate their discomfort, hunger, or thirst to the care team. The team can then work with the patient to balance the need for energy and hydration with the necessary safety precautions for their specific labor course.