**Yes—10–12 hours at night can be okay for a healthy 4-month-old.** Babies vary widely in their sleep patterns. The key is whether your baby gets enough milk over 24 hours and continues growing well. The American Academy of Pediatrics says healthy, growing babies usually don’t need to be awakened for feeds. [AAP guidance](https://www.healthychildren.org/English/ages-stages/baby/sleep/Pages/Sleeping-Through-the-Night.aspx)

Letting your baby sleep is generally reasonable if they:

- Gain weight steadily along their growth curve.
- Feed well during the day and have their usual wet diapers.
- Wake normally and are alert and responsive during awake periods.
- Have no medical instructions requiring scheduled overnight feeds.

For babies aged 4–12 months, the recommended total is **12–16 hours of sleep per day, including naps**. Long nighttime sleep can fit within that range. The main potential downside is missing needed nutrition; premature babies and babies with feeding or growth problems may need overnight feeds. Confirm the feeding plan with your pediatrician if any of those concerns apply. [Sleep recommendation](https://pmc.ncbi.nlm.nih.gov/articles/PMC4877308/), [Mayo Clinic feeding guidance](https://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/expert-answers/newborn/faq-20057752)

Continue safe sleep practices: place your baby on their back in a separate crib or bassinet with a firm, flat mattress and fitted sheet; keep blankets, pillows and toys out, and share your room for at least the first six months. [CDC guidance](https://www.cdc.gov/sudden-infant-death/sleep-safely/)

If sleepiness suddenly increases alongside poor feeding or fewer wet diapers, seek medical advice promptly. **Difficulty waking, limpness or breathing trouble needs emergency care.** [NHS warning signs](https://www.nhs.uk/baby/health/when-to-get-urgent-medical-help-for-babies-and-children-under-5/)