Decoding Newborn Sleep: Why Do Newborns Sleep with Their Mouth Open?

New parents are often filled with both joy and anxiety as they learn the intricacies of caring for a newborn. One common concern that might puzzle many is noticing their newborn sleeping with their mouth open. This behavior, while sometimes concerning, is usually normal, but it’s essential to understand why it happens and when it might indicate a need for medical attention.

Understanding Newborn Sleep Patterns

Newborns sleep approximately 16 to 17 hours a day, split into intervals lasting 2 to 4 hours each. During sleep, you might notice a variety of odd behaviors and positions, including the phenomenon of sleeping with an open mouth. Observing your baby's sleep habits offers critical insights into their overall health and development.

Sleeping baby

Common Reasons Why Newborns Sleep with Their Mouth Open

  1. Nasal Congestion: Newborns are nasal breathers for the first few months. Congestion due to mild colds or environmental factors can make nasal breathing more difficult, compelling them to breathe through their mouths.
  2. Developing Airway Anatomy: As newborns grow, the structure of their airways, including the nose and throat, is still developing. This anatomical progression might lead to temporary mouth breathing during sleep.
  3. Sleep Position: The way a baby is positioned during sleep can affect whether they breathe through their mouth or nose. Certain positions may facilitate or hinder airway openness.

Is Mouth Breathing in Newborns Cause for Concern?

Transient mouth breathing in newborns is typically not worrying. However, persistent mouth breathing can be a sign of underlying issues such as obstructive sleep apnea or other respiratory conditions. If you observe the following symptoms, it’s wise to consult a pediatrician:

  • Persistent noisy or labored breathing
  • Frequent waking or sleep disturbance
  • Poor feeding or slow weight gain
  • Excessive irritability or lethargy

Improving Sleep Hygiene for Newborns

Optimizing the sleep environment is crucial for promoting healthy sleep habits in newborns. Here are some tips to improve sleep conditions:

  1. Maintain a Comfortable Temperature: Ensure the nursery is neither too hot nor too cold. A room temperature of around 18-20°C (65-68°F) is generally comfortable and safe for sleeping babies.
  2. Swaddle for Security: Swaddling helps newborns feel secure and may enhance their sleep quality. However, it’s important to ensure that the swaddle is not too tight, especially around the hips.
  3. Use Appropriate Bedding: A firm mattress covered with a fitted sheet is the safest sleep setup for newborns. Avoid loose bedding, pillows, and plush toys in the crib to reduce the risk of SIDS (Sudden Infant Death Syndrome).
  4. Consider Blackout Curtains: Creating a dark, quiet environment can significantly improve sleep quality for babies. Sleepout Home Blackout Curtains are an excellent option for ensuring your nursery remains dark and conducive to sleep, day or night.
Mother with baby and blackout curtains

When to See a Doctor

While most instances of a baby sleeping with an open mouth are benign, ongoing occurrences warrant a medical review. Seek professional guidance if mouth breathing is accompanied by:

  • Signs of difficulty breathing or chronic respiratory noise
  • Recurring respiratory infections
  • Insufficient weight gain or growth issues


Noticing your newborn sleeping with an open mouth can initially be disconcerting, but understanding the common causes helps demystify this behavior. While often part of normal infant development, persistent symptoms should not be ignored. Creating a sleeping environment that promotes healthy breathing, like employing blackout curtains from Sleepout, can help regulate sleep patterns and support overall well-being. By staying informed and observant, you can ensure your baby’s sleep developments are on a healthy track.

Before and after using Sleepout blackout curtains

Remember, a well-rested baby is a happy, healthy baby. By fostering good sleep habits and environment from the start, you contribute significantly to your child’s developmental success.

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