And carbon monoxide is toxic to hemoglobin. Hemoglobin the carrier of oxygen. So once the woman inhales carbon monoxide, the carbon monoxide can bind to hemoglobin and decrease the Vinity of hemoglobin for oxygen. And what that does is it lowers the amount of oxygen content in the blood of that mother and that will lower the amount of oxygen that is received by that developing fetus. So eventually smoking can basically cause many different types of problems. For example, it can lead to premature birth.