Common Tests and Screenings for Pregnant Women

Pregnancy is a delicate moment in a woman’s life. Thus, expectant mothers must take precautions to ensure a healthy and successful delivery and to optimize the baby’s prenatal care and development. Thankfully, experts have some practical recommendations to do just that.

One vital step is to assess the health of the baby during the formative stages through standard medical procedures. Here are some of the common tests and screenings a woman should undergo during pregnancy.

Genetic Screening

Health experts can detect genetic defects before birth, and it’s a given that there are families who have a history of such defects. Therefore, a pregnant woman should undergo genetic testing to determine if the baby has a genetic abnormality. Upon early detection, the doctor or midwife can recommend follow-up steps toward curing the condition.

Some of the common types of screening methods which a pregnant woman can avail of are the following:

• Chorionic villus sampling
• Amniocentesis
• Alpha-fetoprotein (AFP) test or multiple market test
• Ultrasound scan
• Cell-free fetal DNA testing
• Percutaneous umbilical blood sampling

First-Trimester Prenatal Screening Tests

First-trimester screening combines fetal ultrasound and maternal blood testing to diagnose the risk of the fetus having birth abnormalities. It can be done alone or with other procedures.

Among the tests involved are the following:

• Ultrasound for fetal nuchal translucency. This test assesses the back portion of the fetal neck, using ultrasound. It determines if there is an increased fluid or thickening.
• Ultrasound for fetal nasal bone determination. It’s challenging to visualize the nasal bone on some babies with certain chromosomal defects. This procedure is done with an ultrasound between 11 and 13 weeks of gestation.
• Maternal serum (blood) tests. These screenings examine two substances occurring in the blood of all women during pregnancy. These substances are pregnancy-associated plasma protein A and human chorionic gonadotropin. Abnormal levels of both substances signify an increased risk of a chromosomal defect. Health experts may combine first-semester screening tests and maternal blood tests to better assess if a fetus may develop specific congenital disabilities such as Down syndrome.If the results of these tests are abnormal, the pregnant woman should undergo genetic counseling. Experts also recommend other related tests, such as ultrasound, chorionic villus sampling, amniocentesis, and cell-free fetal DNA for a more accurate diagnosis.

Second-Trimester Prenatal Screening Tests

 Second-trimester prenatal screening involves a series of blood tests, otherwise known as multiple markers. These provide information about a pregnant woman’s possible risk of delivering a baby with specific genetic abnormalities. Screening is normally done by taking a blood sample during the 15th to 20th weeks of pregnancy.

Among the multiple markers done are the following:

• AFP screening. This screening measures the presence of AFP in a pregnant woman’s blood. AFP is a protein contained in the fluid surrounding the fetus. A fetal liver typically produces AFP. It goes through the placenta before entering the blood.Among the abnormal signs of AFP level are these:
  • Abnormalities in the abdominal wall of the fetus
  • Defects in the open neural tube
  • Defects in the abdominal wall of the fetus
  • Delivery of twins
• Estriol. It is a type of hormone the placenta produces. It can be used to assess fetal health by measuring maternal blood or urine.
• Inhibin and human chorionic gonadotropin. These are also hormones produced by the placenta.

When results show abnormal levels of AFP and other markers, experts recommend additional testing. An ultrasound, for example, is needed to verify the milestones of a woman’s pregnancy and to examine the fetal spine and other body parts for possible abnormalities. If not, amniocentesis may be done to present a more accurate diagnosis.

Multiple marker screening, however, is not entirely accurate because it is not diagnostic. It only helps identify women who need more types of testing during pregnancy. False-positive results may show a problem though the fetus is healthy. Likewise, false-negative results usually present a good result when the fetus does have a particular abnormality.

Ultrasound

Ultrasound utilizes high-frequency sound waves to create an image of the internal organs. It is a diagnostic technique used to examine fetal growth and the corresponding dates. That is why using reliable ultrasound transducers is crucial to get the result. Experts recommend undergoing ultrasound at varying intervals during pregnancy.

The most common ultrasound procedures performed on pregnant women are abdominal ultrasound and transvaginal ultrasound. There are also several ultrasound-imaging techniques, such as the 2-D ultrasound and 3-D ultrasound.