Babies may put their fingers in their mouth due to stress, a lack of security, or a desire for parental attention. Parents should choose to ignore this behavior unless it becomes very severe, while also ensuring that they provide enough attention and love. Additionally, designing games that require both hands can help distract the baby and reduce the habit of finger-sucking. As for supplementing with calcium and zinc, generally, it is appropriate to start supplementing soon after birth, but it’s best to consult a doctor to determine the appropriate time and dosage for supplementation.