Normal hemoglobin levels generally range from 13.8 to 17.2 grams per deciliter for a male, 12.1 to 15.1 grams per deciliter for a female and 9.5 to 13 grams per deciliter for an infant, states MedlinePlus. A normal hemoglobin for a newborn ranges from 14 to 24 grams per deciliter.
Hemoglobin is a protein in red blood cells that carries oxygen throughout the body's tissues, explains MedlinePlus. Anemia, chronic illness, poor nutrition and excessive bleeding are possible causes of low hemoglobin levels. Common causes of high hemoglobin levels include certain birth defects involving the heart, right-sided heart failure, severe chronic obstructive pulmonary disease and other serious lung problems.