[header] How to choose maternity pants [title] Wait until you truly need maternity pants. [step] You probably have some clothing in your closet that will see you through the first few months of your pregnancy. You may have loose-fitting dresses, for example, or pants with elastic waists. 
At a minimum, wait until the third month of your pregnancy-longer if possible. This will give you a better idea of how much weight you are gaining and how you are carrying the weight, increasing your odds of making smart clothing purchases.