Blood test for pregnancy - AFP and Multiple Marker Screening

Blood test for pregnancy - Blood Group, Rh Factor, AFP, and Multiple Marker Screening

You'll go through a number of prenatal tests throughout your pregnancy. During your first prenatal visit, you'll get a blood test. The blood test will determine your Blood type, your Rh factor, your Iron level to check if you're anemic, your Blood Glucose level to check for Gestational diabetes and you'll also be tested for some other infections which can affect you and your unborn baby during pregnancy.  Your blood test will check for problems such as cystic fibrosis, rubella (German measles), sickle cell anemia, sexually transmitted diseases, and many more which can affect you or your baby during your pregnancy.

Blood test for pregnancy

These blood tests are usually taken twice in pregnancy - First blood test during your first prenatal visit and second blood test at around 28 weeks of pregnancy but it may be possible that you may get another blood test depending on your preference and health. The first blood test will be offered in early pregnancy which will look at the following :

Blood Group

Your doctor will take your blood sample to check your blood group, cell counts, and hemoglobin. It is useful to know your blood group in case you need to be given blood if you have heavy bleeding during pregnancy (Hemorrhage) or at the time of childbirth.  You'll get a blood test during the second trimester to recheck your hemoglobin which is a protein that carries oxygen throughout the body. 

Rhesus factor (Rh factor)

Rh factor looks for a protein on the surface of Red Blood Cells (RBCs). Most of the people who have Rh factors are Rh-positive and the people who don't have the Rh factor are Rh-negative. If your blood type is Rh-negative and your partner's blood type is Rh-positive then it is possible that a fetus may inherit the father's Rh-positive blood and it can cause your body to make antibodies that will attack the fetus causing a condition in the child called Hemolytic Anaemia. This condition is more of a concern during the second pregnancy. But this condition can be prevented by a vaccination which is done around the 28th week of pregnancy and again 72 hours after the delivery of the first child. If you're Rh-negative you'll get another blood test to recheck your antibodies. 


Your blood test will also look for such infections that can affect you or your baby. Your blood is tested to check whether you have the following infections :

  • HIV (Human Immunodeficiency Syndrome)
  • Syphilis
  • German Measles
  • Sickle Cell Anaemia or Thalassemia 
  • Hepatitis B
  • Hepatitis C
  • Gonorrhea
  • Chlamydia


As your baby needs sufficient blood supply and requires oxygen and other nutrients so your body needs extra iron during pregnancy. Iron deficiency is very common in women during pregnancy. To avoid anemia a pregnant woman needs to take iron-rich food. She also requires iron supplements particularly from the 19th week of pregnancy. To avoid anemia your iron levels will check in regular intervals throughout your pregnancy.

Multiple Marker Screening

During the second trimester of pregnancy, a pregnant woman offered a Triple Screen Test which is also known as Multiple Marker Screening. This test is usually done between 15 to 22 weeks of pregnancy but the best time considered for this test is between 16 to 18 weeks. This test can detect abnormalities such as Spina Bifida, Trisomy 18 Syndrome, Down syndrome. It checks the mother's blood for both chromosomal abnormalities and neural tube defects. A pregnant woman's blood is tested for three substances during this test. The screening test looks for the abnormal level of these substances. These three substances are :

  • AFP (Alpha-Fetoprotein) or MSAFP (Maternal Serum Alpha-Fetoprotein) - AFP is a protein produced by the fetal liver. It is present in the fluid which surrounds the fetus called amniotic fluid. AFP crosses the placenta in the mother's blood. 
  • HCG (Human Chorionic Gonadotropin) - HCG is a hormone that is produced by the placenta.
  • Inhibin - A hormone produced by the placenta.
  • Estriol - A hormone produced by the placenta.

The second blood test will be offered in the second trimester at around 28 weeks of pregnancy which will look at :

Gestational Diabetes

Diabetes is a condition that causes a high level of sugar (glucose) in the blood. A high glucose level may be a sign that you have Gestational Diabetes. It is a type of diabetes that affects many women during pregnancy. In most of the cases, it usually develops in the third trimester of pregnancy particularly after 28 weeks of pregnancy. You'll get a blood test during the second trimester to check for diabetes. 

Accuracy of a blood test for pregnancy

Blood pregnancy tests have an accuracy of 98-99 %. It measures HCG in your blood and provides accurate results.

Blood test for pregnancy cost

The cost of a Blood pregnancy test ranges between $50 to $60.

Also, read other 'pregnancy-related' articles:
Disclaimer: This content is intended for general information only and it should not be used as the basis of patient treatment. The given content is not intended to be a substitute for professional medical advice, treatment, or any diagnosis. Always consult a doctor for more information. Our website doesn't claim responsibility for this information.

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