Hemoglobin is a protein in red blood cells that carries oxygen throughout the body.
It indicates anemia, in women, when hemoglobin levels are lower than 12 grams per deciliter.
It's common to happen in pregnant women.
Hematocrit is also lower that normal ( 36 to 48% for women). Hematocrit is the fraction of blood that is made up of red blood cells. It's important to be measure when suspecting of anemia.