Pregnancy is one of the most emotional and unique journeys, though it may be burdened with lots of challenges and changes. Your health and that of your baby are the most important during this time, so prenatal check-ups are necessary to ensure everything is running smoothly.

Let's go into the most important routine tests you should go through during pregnancy, as well as some optional screenings.

Essential Tests for Every Pregnant Woman

These are key tests that are highly recommended for all pregnant women: (1)(2)

1. Initial Tests (As Soon as Pregnancy is Confirmed)
   • Essential blood and urine tests include:
     • Complete Blood Count (CBC).
     • Blood type and Rh factor.
     • Iron and ferritin levels.
     • Urine test to detect any possible infections or other health issues.
     • Indirect Coombs test
     • Screening for sexually transmitted infections (STIs) – such as syphilis, hepatitis B & C, and HIV.
     • Additional tests (thyroid function tests and blood sugar levels, depending on the medical history and risk factors).

2. Early Ultrasound (Week 6–12)
   • The first ultrasound is an essential scan and should be done between weeks 6 and 12 of pregnancy. Its purpose is to:
   • The first ultrasound is an important scan and thus needs to be carried out between weeks 6 and 12 of pregnancy. Its purpose is to:
     • Determine the gestational age and approximate due date.
     • Check the baby's heartbeat and health condition.
     • Distinguish the number of babies and detect the case of ectopic pregnancy.

3. Second Ultrasound (Anatomy Scan) (Week 18–22)
   • This detailed ultrasound allows the doctor to thoroughly examine the baby's organs and check for any congenital abnormalities or structural defects in the heart, brain, spine, kidneys, and limbs.

4. Gestational Diabetes Test (Week 24–28)
   • This test is done to detect gestational diabetes, a condition that can develop in the second or third trimester of pregnancy. It is typically performed in the sixth month (between weeks 24–28).
   • The test requires a special type of blood sugar screening called the Oral Glucose Tolerance Test (OGTT). For this test to be done, fasting blood sugar is measured when you arrive at the lab, then you will be asked to  drink a glucose solution containing a specific amount of sugar, after that the blood sugar is tested one hour after drinking the solution. A second test is done two hours after drinking the solution, and once the test is complete, you can leave the lab.

5. Group B Strep (GBS) Test (Week 35–37)
   • The test is done by usually swabbing the vagina and rectum, then sending this to a laboratory for bacterial culture in search of the presence of Group B Streptococcus (GBS).What You need to Know:
     • GBS is a bacteria that can normally live in the vagina or rectum and not cause any problem for Mom. It may pass to the baby during delivery and cause serious complications; hence this test is done. GBS is not a sexually transmitted infection, it is a normal flora or bacteria of the body. If this is positive, the mother will receive IV antibiotics during labor to reduce the chance of passing the bacteria to the baby.
     • If the test result is positive, the mother will receive IV antibiotics during labor to reduce the risk of passing the bacteria to the baby.

6. Late Pregnancy Ultrasound (Week 30–40)
   • This scan is optional but may be recommended if there are concerns about the baby’s position or placental health. It helps to check the baby’s position (head-down or breech) and check the placenta and amniotic fluid levels. It also helps in estimating the baby’s size and weight.

Optional Tests

These tests all serve to determine the likelihood of the baby having chromosomal abnormalities or birth defects. It is entirely optional, depending on the medical history and risk factors, based on either the mother's preference or a doctor's recommendation.

Some parents do not get these tests because they would rather not know if their baby will have an issue. Other parents opt for these tests to be better prepared, should there be any issues regarding their child.

Optional screenings fall under three categories primarily: (3)

1.  First-Trimester Screening

• Timing: Done early in pregnancy, between weeks 11–14.
• Purpose: It assesses the risk for certain chromosomal abnormalities, such as Down syndrome , Edwards syndrome, and Patau syndrome.
• Accuracy: 84–90% for detection of Down syndrome.
• This screening Includes:
  
  • Ultrasound scan:   It measures the nuchal translucency, that is, the thickness of the fluid behind the baby's neck.
  • Maternal blood test : Measures levels of PAPP-A protein and B-HCG hormone.

2. Second-Trimester Screening

• Timing: Performed between 15–22 weeks of pregnancy.
• Purpose: This test estimates the risk of having Down syndrome, Edwards syndrome, and neural tube defects such as spina bifida.
• Accuracy: Only 75–80% of cases with Down syndrome are picked up using this, thus it is not as good as the first-trimester screening or NIPT.
• When is it used? The test is offered to women who did not get early screening in the first trimester. This screening includes a blood test that measures the four important substances in the mother's blood:
  
  • AFP (Alpha-Fetoprotein): This helps in the detection of open neural tube defects in the baby's spine and brain. 
  • β-hCG (Beta-Human Chorionic Gonadotropin): This assesses the risk for chromosomal disorders, such as Down syndrome.
  •  uE3 (Unconjugated Estriol): Provides insight into placental health and fetal development. 
  • Inhibin-A: Enhances the detection of Down syndrome.

3. NIPT (Non-Invasive Prenatal Test)

• Timing: Can be done anytime from week 10 onwards.
• Purpose: Detects chromosomal abnormalities with very high accuracy.
• Accuracy: 99% for detection of Down syndrome. It can also detect Edwards syndrome, Patau syndrome, and sex chromosome disorders (such as Turner syndrome or Klinefelter syndrome). Some versions of this test can screen for additional chromosomal abnormalities as well.
• This screening Includes: A blood test from the mother is analyzed to detect tiny fragments of the baby’s DNA that have entered the mother’s bloodstream.

Although these screenings are optional, they may be important or recommended in certain cases, such as:

• The mother is 35 years or older.
• A family history of chromosomal, genetic, or congenital conditions.
• Abnormal ultrasound findings, such as increased fluid behind the baby’s neck.

Note: These tests are screening tests only and cannot diagnose a condition but indicate if one is likely to occur. See your doctor to decide which test is best for you, depending upon your medical history and personal risk factors.

Common Question: What is the difference between 2D, 3D, and 4D ultrasounds? (4)(5)

Ultrasound is one of the most important pregnancy tests, giving pictures of the baby from different angles to monitor development and growth. However, there are three types:

• 2D Ultrasound: This is the standard and essential scan used to check the health of the baby, detect possible birth defects, and assess the amniotic fluid. In most cases, this is sufficient for routine monitoring.

• 3D & 4D Ultrasound: These are not routine ultrasounds but may be advised in certain conditions, such as the suspicion of some congenital malformations like cleft lip or spina bifida. They provide higher resolution images compared to 2D scans, thus giving clearer details for the evaluation of structural birth defects.

• 4D Ultrasound: This is the most advanced ultrasound. While a 3D scan produces still images, 4D ultrasound produces a video of the baby moving inside the womb, enabling parents to view facial expressions and movements in real time.

Your Health and Your Baby’s Health Come First

These were the most important tests to consider during pregnancy. Regular check-ups and screenings at a specialized center under the supervision of an experienced doctor are essential to ensure the best level of care for you and your baby.

To learn more about our comprehensive services or to book an appointment with our Obstetrics & Gynecology Department, visit our website.

References

1. American College of Obstetricians and Gynecologists (ACOG) - Routine Tests During Pregnancy
2. Pregnancybirthbaby.org - Ultrasound scans during pregnancy - benefits, about
3. Royal Australian College of General Practitioners (RACGP) - Prenatal testing
4. Mayo Clinic - Fetal ultrasound - Mayo Clinic
5. WebMD - 3D/4D Ultrasound