Early in the first trimester of pregnancy, certain blood tests are done to ensure that mother and fetus are healthy. All pregnant women, regardless of their medical history or genetic background, will undergo initial blood testing. The American Congress of Obstetricians and Gynecologists says blood tests are used to diagnose any existing diseases and infections, screen for conditions that could put the fetus at risk of abnormal development and determine whether additional blood tests may be required during the pregnancy.
Testing for Blood Type
Doctors test blood to determine whether the mother’s blood type is A, B, AB or O. In addition, doctors test to see if the mother’s blood is Rh positive or negative. Rh is a protein in the blood, according to the March of Dimes. Rh negative women, those who don’t have the Rh protein, may create antibodies that fight the blood of the fetus if fetus’s blood is Rh positive. This may cause the fetus to develop anemia. If a blood test shows the mother is Rh negative, she may be treated with medication to prevent her from making the antibodies.
Testing for Infections
In addition to ascertaining blood type, physicians determine if the mother has antibodies to German measles, called rubella, and chicken pox. The presence of antibodies indicates that the mother has immunity to the diseases. Doctors also test blood for the presence of sexually transmitted diseases such as human immunodeficiency virus, which causes AIDS, syphilis and hepatitis B. These diseases can be passed from mother to child. The American Pregnancy Association, a nonprofit pregnancy advocacy organization, notes that physicians also test blood for toxoplasmosis, an parasitic infection that can cause birth defects.
Testing for Other Conditions
Physicians also use blood tests early in the pregnancy to examine factors such as levels of certain proteins, minerals and sugars that can influence the development of the fetus. The American Pregnancy Organization notes that obstetricians measure glucose, iron and hemoglobin. Glucose levels tell the doctor whether the mother has diabetes or is at risk of developing diabetes later in the pregnancy. Levels of iron and hemoglobin–a protein that carries oxygen in the blood–indicate if the mother is anemic and at risk of going into early labor.
If results of the initial blood tests indicate the mother may be a risk of developing certain conditions later on, physicians may choose to continue to do routine blood tests throughout the pregnancy to monitor any changes.
Learn more blood tests:
- MPV Blood Test: What Does High or Low Mean
- MCH Blood Test: Low, High, What does it Mean
- MCHC Blood Test: Low, High, What does it Mean
- RDW Blood Test High: What does it Mean
About this Author
Amber Angelle writes about health, science and technology. Her stories have appeared in Popular Mechanics, Discover and Popular Science. She blogs for Lemondrop and created a blog about brain and behavior at ScientificBlogging.com. She contributed to the textbook Psychology Around Us (Wiley, 2010) and wrote two articles on breast cancer for the encyclopedia Cancer (Salem Press, 2008). Angelle has a master’s degree in pharmacology.
