Doctors recommend several testing and screening procedures for women during their pregnancies. These are called prenatal tests. They are essential to monitor and keep tabs on both the mother's and the baby's health.
It is easy to treat pregnancy complications, birth defects, and genetic abnormalities if they are detected early. Therefore, screening tests are generally followed by diagnostic tests. While screening tests can identify risk factors, diagnostic tests are used to detect and confirm a specific problem.
The laboratory procedures during pregnancy comprise blood and urine tests, as well as testing of tissue samples from the vagina & cervix. The different types of tests during pregnancy are as follows:
- Tests to check and confirm pregnancy
- Regular screening tests to monitor the health of both the mother and the baby
- Testing to identify specific health issues that can increase pregnancy complications
- Diagnostic procedures for high-risk pregnancies
The type of test depends on the stage of pregnancy. They are discussed in detail below.
Prenatal Tests in the First Trimester of Pregnancy
During the first visit, your doctor confirms the pregnancy and checks for health risks. The urine test checks for the hCG hormone to confirm pregnancy. The pregnancy blood test cost for beta hCG is around Rs. 700-800 in metro cities.
The urine sample is also tested for possible signs of infection. The due date is set based on the date of your last menstrual cycle.
The following tests are performed in the first trimester. These early pregnancy tests can be repeated later if your doctor recommends the same.
Complete Blood Count (CBC)
- The CBC test helps to determine the number of different cell types in the blood, such as red blood cells (RBCs), white blood cells (WBCs), and platelets.
- The number of RBCs reveals whether you are anaemic. It basically checks for an iron and vitamin B12 deficiency
- The number of WBCs indicates the number of cells capable of fighting the diseases. A lower WBC count increases the risk of infection.
- The platelet count indicates whether you have a problem with blood clotting.
Blood Group Type and Rh Factor
A blood test is necessary to determine your blood group (A, B, AB, or O) and whether the Rh factor is positive or negative. The blood test cost for ABO and Rh factor is around Rs. 200, and you generally get the report on the same day.
- Knowing the blood group of pregnant women is critical to handling emergencies such as heavy bleeding during birth.
- The Rhesus (Rh) factor is a kind of protein found in red blood cells (RBCs). You are Rh-positive if your blood cells have this protein. Otherwise, you are Rh-negative.
- The mother's Rh factor has to be compatible with that of the fetus. But incompatibility develops if the mother is Rh-negative and the fetus is Rh-positive. Then the mother's antibodies can destroy the RBCs of the fetus.
- Rh incompatibility is generally not serious in your first pregnancy. But this can lead to complications later. Doctors prescribe a shot of Rh-immune globulin at 28 weeks and after delivery to prevent the development of antibodies.
Rubella Testing
- Pregnant women should be checked for rubella antibodies. In the first 16 weeks, rubella infection (also called German measles) can cause serious birth defects such as heart ailments, deafness, and mental retardation.
- Rubella testing can show whether you have been infected previously or if you have been vaccinated. In either of these cases, you will be immune to this disease.
- But the vaccine contains a live virus and is not meant for pregnant women. If you have not been vaccinated, get it done after your delivery.
Blood Testing for Infectious Diseases
- Screening is essential for sexually transmitted diseases such as HIV, syphilis, chlamydia, and gonorrhoea.
- Babies born to mothers infected with syphilis are stillborn. Women below the age of 25 should also be checked for gonorrhoea.
- The hepatitis virus affects your liver. So pregnant women should be tested for hepatitis B and hepatitis C. This infection can be passed on to babies who may develop chronic liver diseases
- HIV screening reduces the risk of HIV transmission from the mother to her child. The treatments include elective C-section delivery and antiretroviral therapy.
Maternal Serum Blood Tests
These tests check the two substances found in the blood of pregnant women.
- Pregnancy-associated Plasma Protein A: This is a type of protein produced by the placenta during early pregnancy. An abnormal level can lead to chromosomal defects.
- Human Chorionic Gonadotropin (hCG): This is a type of hormone produced by the placenta during early pregnancy. An abnormal level can lead to chromosomal issues.
- Both the above tests can together detect genetic defects in the baby, such as Down Syndrome. Genetic counselling is recommended in such cases.
Apart from these tests, vitamin D screening is important for pregnant women to check the bone development of the fetus. You can visit a lab nearby for a blood test to check any of the above risk factors.
Also Read: Double Marker Test in Pregnancy: Normal Range, Procedure, Cost
Prenatal Tests in the Second Trimester of Pregnancy
Testing in the second trimester of pregnancy includes another round of the complete blood count (CBC) test, a blood test for antibodies, and a glucose tolerance test.
Glucose Screening
- A glucose screening test is required to check for gestational diabetes. This is a temporary form of diabetes that develops during pregnancy. You will have to drink a sugary liquid and take the test an hour later to check your glucose levels.
- Gestational diabetes increases the need for cesarean in pregnant women. It also enhances the risk of mothers developing type 2 diabetes later.
The other tests that may be suggested during this period are listed below.
Ultrasound Test
An ultrasound test is performed between 18-20 weeks to check whether the baby's development is normal. The images clearly show the baby's shape and position. High-risk pregnancies may warrant multiple ultrasounds during this stage.
Alpha-fetoprotein (AFP) Test
AFP screening checks the level of alpha-fetoprotein in the blood of pregnant women. Abnormal AFP levels can be a sign of the following issues:
- Down Syndrome
- Wrong Due Date
- Birth of Twins
- Open Neural Tube Defects
A triple marker test checks the level of AFP and two pregnancy hormones to detect any chromosomal problems in the baby.
Amniocentesis
A sample of the amniotic fluid that surrounds the fetus is tested for chromosomal problems and genetic disorders. It is usually performed between 15 and 20 weeks if higher risk factors persist in pregnant women.
Prenatal Tests in the Third Trimester of Pregnancy
Group B Streptococcus (GBS) Test
- A group B streptococcus test is recommended by doctors between 35 and 37 weeks. GBS bacteria are usually found in the vagina and rectum of women. This can cause some serious infections in newborn babies.
- If the GBS test is positive, intravenous antibiotics are given to prevent the infection during labour.
Non-Stress Test (NST)
A non-stress test may be recommended when the due date has passed or if the pregnancy is high risk. The test checks whether the baby is receiving sufficient oxygen and if it responds normally.
Conclusion
Pregnancy is a period that is mixed with great excitement and anxiety in women. While you pray for a safe and healthy delivery, it is not advisable that you leave this matter to chance. Prenatal testing can help you detect and treat health risks at the earliest possible stage. So approach a lab nearby for a blood test to allay your fears and move towards a cheerful pregnancy.
Agilus Diagnostics, a subsidiary of Fortis Healthcare Limited
