Every pregnancy is precious. As they are many complications during pregnancy that results in various abnormality in the baby, it is important that women with pregnancy-related complications get medical attention as early as possible. It is estimated that about 2 – 3% of babies are born with some type of birth abnormalities. These problems may be due to abnormal chromosome, increased mother’s age, maternal diabetes, high blood pressure and many other maternal complications. Earlier, it was difficult to detect complications in an unborn fetus, but now with so many advanced techniques it is possible to detect abnormality in fetus before delivery. Tests that are done in a pregnant women who do not show any obvious symptoms of disease, but is at high risk of developing complications during pregnancy is called as screening tests. This helps to prevent or treat any suspected abnormality in the fetus. One screening test is the triple screening test during pregnancy.
About Triple Screening
As it is very clear from the name, triple screening is done using mother’s blood sample that measures the level of three factors
- alpha-fetoprotein
- human chorionic gonodotropin
- unconjugated estriol
It is also called as multiple marker screening.
Triple screening is called a screening test as it helps only to suspect that there might be some kind of abnormality in the fetus. Remember it is not a diagnostic test. This test only points that the mother is at possible risk of delivering a baby with genetic abnormality.
Performing the test
Triple screening is performed during the 15th to 29th week of pregnancy but test performed during 16th to 18th week of pregnancy is said to give more accurate results. Triple screening test is recommended for women who
- Are above 35 years of age
- Have a previous history birth defect in family
- Suffer from diabetes and have or still using insulin
- Had any viral infection during pregnancy
- Have used harmful drugs or medications during pregnancy
- Exposed to radiations of any type
1. Alpha-fetoprotein (AFP)
Alpha-fetoprotein (AFP) is a protein that is produced in the liver and in the yolk-sac of the fetus. The level of AFP decreases soon after birth. This test is done to screen birth defect, detect liver disorder, and look for cancerous tumor in the fetus. A high level of AFP suggests neural tube defect such as Spina bifida or anencephaly. Mostly, the high level of AFP is because of inaccurate dating of pregnancy.
2. Human chorionic gonodotropin (hCG)
Human chorionic gonodotropin (hCG) is a pregnancy hormone that is produced by the placental cells. In non-pregnant women, the level of hCG is undetectable, but during pregnancy the level of hCG doubles every 2 or 3 days. This test is done during pregnancy to monitor trophoblastic disease (disease in the blastocyst stage) or germ cell tumors. This test is performed as early as 10 days after missed periods, if doctor suspects ectopic pregnancy, trophoblastic disease or germ cell disease.
3. Unconjugated estriol
Unconjugated estriol is produced by the placenta using the precursor cells from fetal adrenal gland and liver. This test in association with AFP and hCG helps to detect the presence of Down syndrome (trisomy 21) and trisomy 18.
Test results- normal and abnormal
As triple screening test is just a screening and not a diagnostic test, it only tells us the possibility of any birth abnormalities.
- Abnormal result of triple screening does not mean that the baby has some birth defect, it only says there may be or may not be any complications.
- The test results are sometime abnormal as the doctor mis-predicts the age of the fetus; the fetus may be too young or too old than the doctor thought. Triple screening does not screen all the birth defects.
- Abnormal triple screening results means that further diagnostic tests are needed. In some cases, doctors prefer to perform a second triple screening test, which is followed by high definition ultrasound.
- Ultrasound scanning helps to find out the exact age of the baby, look at the structure of brain, kidney, heart, and spinal cord for any abnormalities.
- If the second triple screening test still shows abnormal result, then advanced invasive procedures like amniocentesis may be performed. Amniocentesis may help to diagnose any birth defect in the baby.
- Before invasive procedure discussing the pros and cons of the procedures with the healthcare provider is very important.
The advanced screening test is actually a great step forward that helps to have a healthy future generation. Some screening tests during pregnancy are recommended to all pregnant women and some are recommended only to women who are at high risk of complications either to mother or to the baby. Risk factors include family history, any medical complications, and ethnic background or based on the result of previous tests. Identifying the complications at an early stage helps the doctor to find a way to treat or plan for nay special care that is required for the mother and the baby.
