The Scoop on SUID

First published August 2013
Updated February 2026

Sudden Unexpected Infant Death (SUID) often raises concern among parents and caregivers. While the condition is rare, it remains the leading cause of death among infants between one month and one year of age.

What is SUID?

SUID is a broad term for infant death that includes Sudden Infant Death Syndrome (SIDS), accidental suffocation and undetermined/unknown cause of death. SIDS, which is the sudden death of an infant younger than one year of age that remains unexplained after a thorough investigation, is the leading cause of death infants between 1 month and 1 year in the United States.

Although the exact cause of SUID is not fully understood, it may result from a combination of factors, including:

• An underlying vulnerability, such as subtle differences in brain development or genetic factors.
• A critical developmental period, when an infant’s ability to regulate breathing, heart rate or arousal is still immature.
• An external stressor, such as reduced airflow, smoke exposure or infection.

Strategies to Reduce the Risk

The hard truth about SUID is that parents can do everything “right” and still suffer the loss of an infant to SUID. There is no guaranteed way to prevent SIDS, but there are ways to decrease the risk.

Following safe sleep guidelines is one way to help reduce the risk of SUID.

• Place infants on their back for every sleep, including naps.
• Use a firm, flat sleep surface, such as a crib or bassinet mattress covered with a fitted sheet.
• Keep the sleep area free of soft objects, including blankets, pillows, stuffed animals, crib bumpers or loose bedding.
• Share a room, not a bed.

Additional factors that can help reduce the risk of SIDS include:

• Avoid smoke exposure during pregnancy and after birth. Both prenatal smoking and secondhand smoke significantly increase SIDS risk.
• Ensure regular prenatal care during pregnancy.
• Keep immunizations up to date, as evidence shows vaccinated infants have a lower risk of SUID.

There are other factors that might help protect against SUID but are not well proven. These include breastfeeding, avoiding overheating the infant, using a fan in their room and using a pacifier as they fall asleep (but not reinserted once asleep).

SUID can occur even when families follow all recommended guidelines, and it is important to acknowledge that no single action guarantees prevention. Consistently practicing evidence-based safe sleep habits can help reduce risks and support infant health and safety.