Infertility is a common problem, and it can happen even if you' ve been pregnant before. In the United States, as many as 15 in 100 couples have trouble getting pregnant. If you are trying to have a baby and have not gotten pregnant, you and your partner may need an infertility evaluation. Exams and tests can be done to try to find the reason why you and your partner have not gotten pregnant. In this booklet, you' ll learn how pregnancy works, some possible causes of infertility and multiple miscarriages, what tests you might need, and what treatments are available.