Prenatal Testing

To find risk factors for maternal and fetal pregnancy complications, many tests are routinely performed according to gestational age. Tests performed at the time of preparing for pregnancy or early pregnancy include general blood test, blood test, urine test, rubella test, hepatitis B test, hepatitis C test, sexually transmitted disease test, AIDS test.

The First Trimester ( ~ 13weeks and 6 days of gestation)

The ultrasound exam, called a nuchal translucency, measures the thickness of a space at the back of the fetus’s neck. An abnormal measurement means there is an increased risk that the fetus has Down syndrome or another type of aneuploidy. It also is linked to physical defects or the heart, abdominal wall, and skeleton.

Cell-free DNA is the small amount of DNA that is released from the placenta into a pregnant woman’s blood stream. The cell-free DNA in a sample of a woman’s blood can be screened for Down syndrome, trisomy 13, trisomy 18. This test can be done starting at 10 weeks of pregnancy. It takes about 1 week to get the results. A positive cell-free DNA test result should be followed by a diagnostics test with amniocentesis or CVS.

CVS is a type of diagnostic test and a procedure to get sample of placental tissue for karyotype. CVS is performed earlier than amniocentesis, between 10 weeks and 13 weeks of pregnancy.

The quad blood test measures the level of four different substances. The quad test screens for Down syndrome, trisomy 18, and neural tube defects. It is done between 15 weeks and 22 weeks of pregnancy.

The integrated test is integrated test between first- and second-trimester. The resulting outcomes are more accurate than a single test result.

Results of blood screening tests for aneuploidy are reported as the level of risk that the disorder might be present. Diagnostic testing with CVS or amniocentesis that gives a more definite result is an option for all pregnant women.

It is a test to diagnose fetal chromosomal abnormalities performed after 15 weeks of pregnancy. Ultrasonically induced fetal amniotic fluid is drawn through the needle and fetal genetic test is performed with amniotic fluid. The likelihood of lethal complications for both mother and fetus is extremely low.

In the mid-trimester, ultrasonography can confirm the presence of anatomic malformations of the fetus. It is generally conducted between 18 and 22 weeks of gestation. As the technological development of the ultrasonic equipment has increased the accuracy of test results, importance of the exam has also increased greatly. Depending on the degree of fetal malformations diagnosed by prenatal ultrasonography, appropriate and systematic prenatal care, delivery planning, and consultation and planning for neonatal care should be planned.

Tests to evaluate the health of the fetus are conducted from the 32nd to the 34th week of pregnancy, and if necessary, fetus is monitored until the time of delivery. The tests include fetal movement assessment (“kick counts”), Nonstress test (NST), Biophysical Profile (BPP), Modified Biophysical Profile, Contraction Stress Test, and Doppler Ultrasound.

If abnormal fetal growth, inadequate amniotic fluid volume, or other high risk factor is detected through ultrasonography, Doppler examination can be performed to examine placental fetal blood flow and uterine placental blood flow and further tests can be conducted to assess fetal condition if needed.