Gastroesophageal reflux in the newborn

Gastroesophageal reflux (GER) in newborns is a very common phenomenon in the first months of life. It is defined as the retrograde movement of gastric contents toward the esophagus and the oral cavity, which frequently occurs without pathological implications. This physiological event should not be confused with gastroesophageal reflux disease (GERD), which is characterized by clinical complications such as pain, persistent irritability, feeding difficulties, or inadequate growth. While GER is generally a benign and temporary condition, GERD requires medical intervention to avoid more serious complications.

Physiology of the infant gastrointestinal tract

The gastrointestinal tract of the newborn has some anatomical and functional characteristics that explain the high incidence of reflux in the first months of life. In the newborn and infant, the Lower Esophageal Sphincter (LES), or Lower Esophageal Sphincter (LES) in English, is functionally immature and exhibits frequent relaxations independent of the swallowing act. These relaxations, called Transient Lower Esophageal Sphincter Relaxations (TLESR), represent a physiological phenomenon and occur with a frequency of about one every one to two minutes. They allow the release of gastric air, but during these episodes, the ascent of small amounts of milk or gastric contents into the esophagus, determinando rigurgiti, even repeated throughout the day.
This mechanism is considered the primary cause of physiological regurgitation in infants.

 

Liquid diet and esophageal protection in the infant

The newborn’s stomach has a limited capacity and accommodates a liquid diet, primarily breast milk or formula. Since milk is less viscous than solid foods, it is easier for it to rise into the esophagus.
The immaturity of the LES, combined with the liquid diet, favors an increased frequency of regurgitation, without necessarily implying pathological reflux. In the healthy infant, numerous micro-reflux episodes are therefore common, generally well tolerated and not associated with mucosal damage. This condition tends to resolve spontaneously with the progressive functional maturation of the LES, which occurs in most cases within 12–18 months of life.

However, there is a peculiarity: the esophagus of the newborn and child is equipped with effective defense mechanisms, including saliva, rich in bicarbonate with a buffering function, rapid esophageal peristalsis which promotes the clearance of refluxed material and a generally limited acid contact time, especially during wakefulness. These systems explain why, in the majority of cases, gastroesophageal reflux in pediatric age does not cause clinically significant lesions.

 

Distinction between physiological and pathological gastroesophageal reflux

International and national guidelines emphasize the importance of distinguishing between physiological and pathological reflux to avoid overdiagnosis and invasive treatments in infants with simple episodes of regurgitation. A newborn with gastroesophageal reflux (GER) can be classified as physiological or pathological based on the severity of symptoms, the frequency and the effects on the child’s general well-being.
The difference between the two types of reflux is mainly based on clinical manifestations and complications.

 

Physiological gastroesophageal reflux (GER)

Physiological reflux in newborns is an absolutely common condition, especially in the first months of life, and represents a natural phenomenon due to the immaturity of the gastrointestinal system. Le main features include:

• Manifestations: it generally presents with post-feeding regurgitation that can occur several times a day, without signs of significant distress.
• Symptoms: it is often asymptomatic or causes minor disturbances, such as small amounts of milk regurgitation immediately after the meal.
• Development: it has no negative impact on weight gain or the child’s well-being.
• Physiology: the immaturity of the lower esophageal sphincter (LES) and the supine position during sleep contribute to the ascent of gastric contents, which normally does not cause damage.
• Prognosis: most cases resolve spontaneously with growth, generally within 6-12 months, when the gastrointestinal system and the LES mature.

 

Pathological gastroesophageal reflux (GERD)

Pathological gastroesophageal reflux (GERD) is a more serious condition that manifests when the reflux causes persistent clinical symptoms or complications that affect the health and well-being of the newborn. The main features include:

• Manifestations: associated with severe symptoms such as frequent vomiting, persistent irritability, inconsolable crying, refusal to feed, and difficulty in gaining weight.
• Symptoms: pathological reflux is often accompanied by extra-esophageal symptoms such as respiratory problems (chronic cough, wheezing, apnea) and marked irritability.
• Complications: it can lead to esophageal damage (esophagitis), failure to thrive, difficulty feeding and, in extreme cases, anatomical malformations (e.g. pyloric stenosis or esophageal anatomical abnormalities).
• Prognosis: pathological reflux may require medical treatment, such as medications to reduce gastric acidity or, in extreme cases, surgical interventions to correct anatomical malformations.

 

In summary, in physiological reflux, infants show intermittent regurgitation immediately after feeding, which does not cause severe symptoms or interfere with weight gain. However, when reflux is accompanied by persistent irritability, refusal to feed, poor weight gain or persistent respiratory symptoms, diagnostic investigation is necessary to exclude GERD or other underlying conditions.

Clinical studies suggest that fewer than 10% of infants with reflux require specific treatment or further diagnostic investigations, as most cases are physiological and tend to resolve spontaneously with growth. Pediatric guidelines, including those of the European Society for Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN), emphasize the importance of avoiding overdiagnosis and invasive treatments in infants with physiological reflux.

  

Postural positioning after feeding

Positioning the infant after feeding is one of the most important aspects in the management of physiological gastroesophageal reflux symptoms. Keeping the infant in a semi-upright position, with an incline of about 10°, uses gravity to promote gastric transit and limit the ascent of gastric contents into the esophagus. This measure can help alleviate primarily the respiratory symptoms associated with reflux, while not causing a significant reduction in the overall frequency of reflux episodes, which remain physiological.

The gravity, in fact, limits the height reached by the gastric contents, reducing acid contact with the upper portion of the esophagus, which is particularly sensitive to irritation. The containment of reflux at more distal levels contributes to reducing the risk of esophageal inflammation and associated symptoms such as pain, irritability and feeding difficulties.

 

Scientific evidence

The main international guidelines and clinical studies recommending the maintenance of an upright or semi-upright position (10°–30°) after feeding in infants are:

• American Academy of Pediatrics (AAP, 2025): suggests a semi-upright position post-feeding to reduce respiratory symptoms related to reflux, while reiterating that sleep must take place exclusively in the supine position on a flat surface to prevent SIDS.
• Italian Society of Pediatrics (SIP, 2024) and ESPGHAN/NASPGHAN (2018-2022): confirm that the semi-upright posture post-feeding promotes gastric emptying and limits acid contact with the upper esophagus in cases of physiological reflux, without indication for pharmacological therapy.

In clinical settings, it is commonly advised to keep the infant in an upright or semi-upright position for 20–30 minutes after feeding, in order to promote gastric emptying before sleep, while recognizing that direct evidence on the actual reduction of reflux episodes remains limited.

The guidelines NASPGHAN/ESPGHAN do not recommend any positional therapy (including elevating the head of the bed or alternative positions) for the treatment of reflux symptoms during sleep, for safety reasons and lack of evidence of effectiveness. International bodies, including the World Health Organization (WHO) and the AAP, indicate the supine position on a flat surface as the only safe standard for sleep up to 12 months of age, in order to reduce the risk of Sudden Infant Death Syndrome (SIDS). The prone and lateral positions, although they may temporarily reduce reflux in pH recordings, are strongly discouraged for unsupervised sleep due to the increased risk of SIDS (American Academy of Pediatrics (AAP): Sleep Position and SIDS. Pediatrics, 2025).