Sleeping 10 to 12 hours at night can be okay for a healthy 4-month-old and isn’t automatically abnormal or harmful. What matters is whether your baby gets enough milk overall and is growing well. Healthy babies who are gaining weight generally don’t need to be woken for feeds. [American Academy of Pediatrics](https://www.healthychildren.org/English/ages-stages/baby/sleep/Pages/Sleeping-Through-the-Night.aspx)

Steady weight gain, good daytime feeding, normal wet diapers, and being alert and responsive when awake are reassuring signs. Babies aged 4 to 12 months are recommended to get 12 to 16 hours of sleep in 24 hours, including naps. This range is a guide, not a strict limit. [American Academy of Sleep Medicine](https://aasm.org/recharge-with-sleep-pediatric-sleep-recommendations-promoting-optimal-health/)

The main concern with long stretches of sleep is missing feeds your baby needs. If your baby was premature, is gaining weight poorly, has a medical condition, or has been prescribed overnight feeds, check with their pediatrician before letting them sleep that long. Otherwise, bring it up at the next routine visit so the pediatrician can confirm that feeding and growth are on track. [Mayo Clinic](https://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/expert-answers/newborn/faq-20057752)

Get medical advice promptly if your baby suddenly becomes sleepier and is feeding poorly or has fewer wet diapers. If they’re difficult to wake, limp, or having trouble breathing, seek emergency care. [NHS](https://www.nhs.uk/baby/health/when-to-get-urgent-medical-help-for-babies-and-children-under-5/)

For safe sleep, place your baby on their back on a firm, flat, empty sleep surface. Use their own crib or bassinet in your room for at least the first six months. [NIH](https://safetosleep.nichd.nih.gov/reduce-risk/reduce)