• What is the First Trimester Combined Screening?

• Why and when it is done?

• How is this screening done?

• When are the results available?

• What do the test results mean?

• Additional Provided by the Screenings

What is the First Trimester Combined Screening?

The First Trimester Combined Screening is also called the first-trimester screening test (FTS) or enhanced first-trimester screening.  This test is a combination of a maternal blood test and a fetal ultrasound that helps in detecting the risk of a fetus with birth defects.

Why and when it is done?

This test is safe and optional, but it helps expecting parents and their fetal specialist assess the potential health risks to the fetus. The ultrasound test is usually offered between 11 to 14 weeks of gestation while the blood test is taken around 9 to 14 weeks.

How is this screening done?

This combined screening is usually done in two parts: one is a blood test while the other one is an ultrasound.

Blood Test: The blood sample is taken with a finger prick. From the taken sample two protein levels: Pregnancy-Associated Plasma Protein-A (PAPP-A) and Human Chorionic Gonadotropin (hCG) are measured. Abnormal levels of these two proteins indicate a higher risk of chromosomal abnormalities.

Ultrasound Measurement (Nuchal Translucency or NT Scan): The ultrasound measures the fluid amount behind the fetus’s neck. Every fetus has some fluid but if its measurement is higher it may point to a higher risk of a chromosomal disorder. This test is not a normal ultrasound but a special one that requires a trained radiologist and it's not carried at every pathology.

Then the above data is combined with the mother’s age and other factors to calculate the risk of chromosomal abnormalities in the fetus.

When are the results available?

Ultrasound results are obtained on the same date while blood tests take an ample time of a week or two. These test reports are then to be shown to your health provider to access better knowledge of your baby.

What do the test results mean?

These tests are screening tools, not diagnostic, and they estimate the risk rather than provide a definitive diagnosis. If a high risk is detected, further diagnostic tests like chorionic villus sampling (CVS) or amniocentesis may be recommended.

Test results are presented as a risk ratio. For instance, a ratio of 1 in 50 indicates a higher risk of chromosomal abnormalities, while 1 in 10,000 indicates a lower risk.

Additional Provided by the Screenings

This screening is conducted to gain insights into the fetus’s likelihood of having birth defects like Down syndrome, Edwards syndrome, or Patau syndrome. But apart from such fetal abnormalities, it can also help in giving other useful information like accurate dating of the pregnancy, fetal heart rate, number of fetuses present, and whether twins are identical or fraternal.

If you have concerns about your pregnancy or are considering the First Trimester Combined Screening, don’t hesitate to reach out. Consulting with a trusted fetal medicine specialist can provide you with the reassurance and guidance you need during this important time. Take the next step towards ensuring your baby’s health—schedule an appointment today and get the support you deserve.