“What blood tests are done during pregnancy?”

This is a good question, but unfortunately it has no easy answer. As a 22 year old you might have had blood drawn for a pregnancy test early in your pregnancy to help make sure the pregnancy was well established, however such testing is not really needed unless you had a history of prior problems, like a previous ectopic pregnancy or serious tubal disease.
Blood tests can be done to help detect metabolic problems like diabetes or thyroid disease that can be affected or revealed during a pregnancy.
At some point in your pregnancy you might have a complete blood count and metabolic panel. If you don't already know your blood type you might have a blood test to see if you are rH negative. If you have had previous transfusions you might have a test to see if you have antibodies to other blood types that could attack you fetus if it has one of those blood types.
If you were a little older you might have a blood test to detect cell free DNA of your baby to see if there are genetic problems.
The answer is that one size does not fit all, every individual may need a different approach and different testing depending on who they are and what conditions they have. You should ask your medical provider to explain what testing is ordered and what its purpose might be.
It possible that your mother and grandmother had no testing at all during their pregnancies. Pregnancy is, after all, a natural condition and could proceed without testing. Modern testing offers a way to diagnose some problems once symptoms occur, or based on a person's medical history. But a normal pregnancy might require no blood tests at all in a young women.

In the first trimester a complete blood count, syphillos rubella, hepatitis and hiv. Depending on your history you may be offered genetic testing. Later you will get a test for spina bodies and diabetes

There are several done at different times during the pregnancy. At the beginning a blood type and antibody screen are done along with CBC (complete blood count to check for anemia, etc.), HIV, hepatitis B, rubella, RPR to check for syphilis, and a screening test for carriers of certain diseases and chromosomal problems with the fetus are offered. Later in the pregnancy testing is done for another CBC, RPR and glucose tolerance test. There are other tests which are not blood tests.

During the first trimester, there are a series of labs which include the blood type, blood count, hepatitis profile, syphilis, HIV, rubella, and cystic fibrosis screening. At or around 28 weeks, screening for diabetes is done and repeat of blood count is done. Hope this helps. Depending on different medical and social history, we may have to add herpes, toxoplasmosis, and/or cmv.

Blood draws are basic prenatal panel which may have minor variations from state to regions. Also are prenatal screening for potential .malformations which are recommended. Depending on your or your partner's family history or ethnicity, other genetic testings could be done as well.

There are several blood tests that we do on everybody including a complete blood count, syphilis testing, HIV testing, gonorrhea chlamydia testing, etc. All that testing is to make sure that we don't have a risk of passing any infections to a baby. There's optional testing you can do for genetic testing as well.

Doug Young, MD