What is the best sleep position to minimize benign sleep myoclonus of infancy (BSMI) in infants?

Sleep Positioning for Benign Sleep Myoclonus of Infancy

There is no specific sleep position that minimizes benign sleep myoclonus of infancy (BSMI), and all infants—including those with BSMI—should be placed supine (on their back) for every sleep to reduce mortality risk from SIDS. 1

Why Sleep Position Does Not Affect BSMI

The clinical characteristics of BSMI demonstrate that myoclonic jerks occur exclusively during sleep regardless of position:

• BSMI occurs during non-REM sleep stages and is not position-dependent—the jerks happen whether the infant is supine, prone, or lateral 2, 3
• The myoclonic events are triggered by the sleep state itself, not by body positioning 2, 4
• In studied cases, jerks occurred during drowsiness, deep sleep, and before awakening, demonstrating no correlation with specific positioning 2

Mandatory Supine Positioning Takes Priority

Despite BSMI being benign and self-limited, supine positioning must be maintained for all sleep periods until 1 year of age to prevent SIDS mortality:

• The supine position reduces SIDS risk by approximately 50-70% compared to prone positioning 5
• The AAP recommends supine positioning for every sleep by every caregiver until the infant reaches 1 year of age 1, 6
• Side sleeping is not safe and should not be used, as it is unstable and increases risk of rolling to the prone position 6

Clinical Management Approach

The key is recognizing BSMI as a benign condition that requires no intervention, while maintaining safe sleep practices:

• BSMI typically begins within the first 15 days of life (median 3 days) and resolves spontaneously by 2-10 months (median 2 months) 2, 3, 4
• The jerks stop abruptly when the infant is aroused, which distinguishes BSMI from epileptic seizures 2, 3
• No antiepileptic drugs should be prescribed for BSMI 4
• EEG during myoclonic events shows no paroxysmal activity, confirming the non-epileptic nature 2, 3

Common Pitfall to Avoid

Do not alter safe sleep positioning in an attempt to reduce BSMI episodes. Parents may observe that their infant has myoclonic jerks during supine sleep and mistakenly believe that changing position will help. However:

• Changing to prone or side positions does not reduce BSMI and dramatically increases SIDS risk 5, 6
• The myoclonus will resolve spontaneously regardless of sleep position 2, 4
• Mortality prevention from SIDS must always supersede attempts to minimize benign, self-limited movements 1, 6