Pregnancy is the period of time when a fetus develops inside a woman’s uterus and ends with the birth of the infant. Pregnancies typically involve a variety of clinical laboratory tests. The tests provide useful information from the time pregnancy is first considered through the initial days of the newborn’s life. Some of these tests are performed at specified times throughout the pregnancy. Others are ordered as needed to detect and address conditions or problems that arise during pregnancy. Still others are offered to women who have increased risks because of their age or lifestyle and, finally, certain tests are selectively chosen based on the personal and family medical histories of the woman and her partner.
The purposes of prenatal tests are to screen for and diagnose any existing problems that may affect the mother’s or baby’s health, identify and address problems as they arise, and assess the risk of a baby having a chromosomal or genetic abnormality. The tests generally require just a small sample of easily obtained blood, urine, or cervical cells.
When a woman is considering having a child, she and the prospective father should consult with their health care provider(s). Based on the family and medical histories of the biological parents, certain tests may be recommended to help ensure as healthy a pregnancy as possible. These tests include genetic testing for certain inherited diseases and disorders to understand the risk of having a child with one of these and tests to detect any infections or conditions that the mother-to-be may have that could put her or her unborn baby at risk.
Testing that may be offered to the woman and her partner to evaluate the risk of inherited diseases are:
Genetic testing for inherited diseases
Genetic testing for hemoglobin disorders
Cystic fibrosis carrier testing
Testing that may be recommended to the woman either when she is considering a pregnancy or at one of her first prenatal visits include:
Immunity to rubella (German measles) test
Human immunodeficiency virus (HIV) antibody test
Gonorrhea, chlamydia, and syphilis tests
Hepatitis B screening
Women with special health considerations like diabetes or high blood pressure (hypertension) should have those under control before getting pregnant. Women with type 1 or type 2 diabetes are strongly encouraged to have an A1c test at least 3 to 4 months before they hope to conceive. This is because diabetes-related birth defects happen early in the pregnancy, well before most prenatal visits. Having this test helps the woman identify a safe time to try to become pregnant. Conceiving when blood sugar is well controlled (and maintaining tight control during the first trimester) helps prevent birth defects and miscarriages.
"Pregnancy & Prenatal Testing." Lab Tests Online. 7/6/11. Lab Tests Online, Web. 9/2/11.