1-month-old baby spitting up milk?

Spitting up milk is very common in 1-month-olds. The most common cause is that the valve between the baby's stomach and esophagus (lower esophageal sphincter) hasn't fully matured yet. This is why milk can easily come back up after feeding.

General information and suggestions:

• Normal spitting (reflux): Usually just a small amount dribbling from the mouth after feeding. Baby appears comfortable, is gaining weight well, and isn't fussy. Most babies outgrow this between 6–12 months on their own.
• What you can do:
• Keep baby upright for 20–30 minutes after each feeding.
• If possible, pause once or twice during feeding to burp.
• Avoid overfeeding.
• Place baby on their back when sleeping (reduces SIDS risk and is safe for reflux).
• When to see a doctor:
• If vomiting is projectile (shooting out) and happens at every feeding.
• If vomit contains bile (greenish/yellow color) or blood.
• If baby isn't gaining weight or is losing weight.
• If baby is extremely fussy, cries a lot, or has difficulty breathing.
• If vomiting started suddenly and is accompanied by fever (sign of infection).

In short, if your baby generally seems happy, is gaining weight well, and spitting up is minimal, this usually isn't something to worry about and will pass with time. If any of the warning signs above are present, definitely see your pediatrician.