Prenatal screening tests

Pregnancy screening tests are the basis of today's prenatal care, and they are important for monitoring and detecting possible problems related to pregnancy or the baby's health. Screening tests are preventive and completely non-invasive and serve exclusively to detect a problem and the need for further testing, not to make a diagnosis. These tests are actually a diagnostic tool that is used for risk assessment of certain conditions or disorders of the fetus.

There are different types of screening tests, and these are some of them:

First-trimester screening or "Double test", is performed between the 11th and 14th weeks of pregnancy, and it's the first basic prenatal test. This test includes an ultrasound examination and blood analysis, and it's preferably to be done on the same day.

Ultrasound examination measures certain parameters and blood analysis measures two hormonal markers - free beta-hCG and PAPP-A (protein). The examination also takes the individual characteristics of the pregnant woman into consideration, age, weight, and the type of pregnancy (twin pregnancy, in vitro fertilization). Based on the results we can detect chromosomal anomalies or chromosomal pathologies, the test is 80% reliable, and it can indicate the presence of Down syndrome and Edwards syndrome. If the results indicate the presence of some anomalies, pregnant women are advised to do the "Triple test".

Screening in the second trimester of pregnancy or the "Triple" and "Quad" test is performed between the 15th and 20th week of pregnancy. For this test we measure the concentration of hormonal markers from the mother's blood and for the Triple test it's the level of alpha-fetoprotein (AFP), estriol and beta-hCGa, and the Quad test includes inhibin A.

Non-invasive prenatal testing – NIPT is one more type of screening test and its an advanced form of screening, which involves the analysis of fetal DNA from the mother’s blood. This type of test can be done from the 10th week of pregnancy, and based on the results we can easily notice chromosomal disorders such as trisomy 21, 18, 13, as well as sex chromosome disorders. The NIPT test has a very high percentage of accuracy and is increasingly used as a standard prenatal test.

The advantages of screening tests are the early detection of genetic abnormalities and defects in fetal development, safety, non-invasiveness, and accessibility. The disadvantages of these tests are limitations because they only focus on certain chromosomal disorders and do not cover all possible genetic or developmental disorders. Besides these tests aren't 100% sure in terms of accuracy, and they do not provide a definitive diagnosis.

Screening tests are an indispensable part of prenatal care during pregnancy, allowing us to monitor the health of the pregnant woman and baby with additional information about possible problems.

*This text is intended for informational purposes only. If you experience any symptoms, it is recommended that you seek advice from your doctor or a qualified healthcare professional.*

*Image taken from the site:https://pixabay.com/photos/baby-belly-body-child-expectant-18937/

Reference

NHS. (n.d.). Screening tests in pregnancy. NHS. https://www.nhs.uk/pregnancy/your-pregnancy-care/screening-tests/

Johns Hopkins Medicine. (n.d.). Common tests during pregnancy. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/common-tests-during-pregnancy

Centers for Disease Control and Prevention. (n.d.). Birth defects screening. CDC. https://www.cdc.gov/birth-defects/screening/index.html