Most parents-to-be can't help but have occasional worries about their baby's health. Fortunately, the vast majority of children born in this country are healthy. Prenatal tests are available to put your mind at ease -- though, ironically, thinking about the test results is part of what makes expectant parents nervous. Remember that the results of prenatal tests usually provide reassurance that your baby is thriving. Learn about four common procedures and why your doctor will recommend at least one of them.