Prenatal screening tests or pregnancy tests can help you get the health details of your unborn baby. Such tests can provide invaluable information about your developing fetus during pregnancy, particularly those that look for genetic abnormalities and birth problems. The first and second trimesters are when most screening tests are carried out. It’s crucial to remember that screening tests are what they claim to be: screening exams. They are not diagnostic tests that can confirm whether your baby has a specific problem; they merely provide you with a risk ratio of potential conditions. You might be given the option of additional diagnostic tests if your baby is deemed high-risk.
First Trimester Screening Tests
Early Pregnancy Scan
Performed at gestational age: 6 to 8 weeks
The early pregnancy scan, also known as viability or dating scan, is typically performed at 8 weeks of gestation. However, it could be done earlier if you’ve previously experienced difficulties such as pain, bleeding or spotting. This test confirms the location of pregnancy whether it is within the uterus i.e intrauterine or outside the uterus- ectopic pregnancy, which could be life threatening. By confirming the pregnancy’s viability through the heartbeat, this scan gives the details of the current condition of an unborn baby. It also identifies whether you are carrying a singleton or multiple fetuses and calculates the gestation of the pregnancy.
Nuchal Translucency Scan
Performed at gestational age: 11 to 13 (+6 days) weeks
The time between the 11 and 13 (+6 days) weeks of pregnancy is typical for the nuchal translucency ultrasound. The scan is often done transabdominally, but your doctor may decide to perform it transvaginally instead if he/she feels it essential. The scan is carried out to determine the gestational age of the pregnancy.
However, looking for multiple gestations and determining an individual risk score for chromosomal abnormalities is advised. Age, fetal heartbeat, nuchal translucency thickness, fetal nasal bone structure, fetal heart blood flow, and the ductus venosus are all considered while determining this risk score.
Expecting mothers with a high-risk score may be advised to undergo additional testing (invasive or non-invasive) to obtain a conclusive diagnosis. Additionally, you may be advised to have a Double marker test, which is a blood test that gives a combined risk of possible chromosomal abnormalities in the developing fetus and increases detection rate of fetuses at risk.
Chorionic Villus Sampling
Performed at gestational age: 11 to 13 weeks
An invasive diagnostic procedure called chorionic villus sampling (CVS) is advised for patients at high risk for prenatal chromosomal disorders. A small placental tissue sample is extracted using a fine needle which is put into the pregnant woman’s abdomen. CVS can definitively diagnose chromosome abnormalities and other heritable disorders, but it has a 1-3% risk of miscarriage. If CVS is suggested for you then you and your partner may get advice on the advantages and disadvantages of the procedure.
Second Trimester Screening Tests
Fetal Anomaly Scan
Performed at gestational age: 18 to 22 weeks
An ultrasound test called a fetal anomaly scan examines a baby’s intricate anatomy between the 18th and 22nd week. Your doctor will examine the entire fetus during this scan to assess growth, the location of the placenta, and the amount of amniotic fluid present. This test also gives you an insight into your baby’s brain, spine, face, stomach, heart, colon, kidneys, and limbs.
Performed at gestational age: 16 to 20 weeks
The fluid surrounding the fetus is removed via an invasive surgery called amniocentesis, and samples are taken to check for chromosomal abnormalities. It might be advised if your nuchal translucency and blood test results indicate that you are at high risk for fetal chromosomal disorders. Amniocentesis carries a small chance of miscarriage, much like CVS. If you choose to have it, you will be advised on the advantages and disadvantages of the procedure to assist you in making a more informed choice.
Done at gestational age: 15 to 20 weeks
The quad marker screening test: This can be helpful if you missed your first-trimester screening and want to know your risk of fetal chromosomal abnormalities. A blood test called the quad marker test calculates a risk score by measuring four fetal proteins. It is less efficient than early blood testing though. Moreover, planning your future moves at this point in your pregnancy may be difficult if you subsequently receive a diagnosis of a fetal defect.
NIPT: Sometimes you may be advised by your fetal medicine specialist to undergo a NIPT test. This is a non-invasive blood test to look for cell-free fetal DNA in mother’s blood. It is an advanced screening test with high sensitivity. It may be advised in certain situations like advanced maternal age or having a previously affected child or family member with Down’s syndrome or if your combined screening in third month shows an intermediate risk for trisomies. Sometimes couples request this test without any of the above indications and it can still be performed.
Pregnancy scans of any kind are risk-free and have little to no side effects. The specific number of ultrasounds varies from pregnancy to pregnancy and is determined by the outcomes of your preliminary exams and scans. Prenatal testing a significant medical advancement can help you be prepared for potential issues in your unborn child. You can guarantee your child a good start in life by keeping up with your screening regimen.
Pregnancy packages at Ankura Hospital give you a decent opportunity to see your unborn child. Contact us if you have questions about our private ultrasound scans. Our maternity specialist doctors also provide you with the best pregnancy care tips to clear your doubts regarding your pregnancy and delivery.