First-trimester screening is a blood test that is used to screen for chromosomal conditions, such as Down syndrome and trisomy 18. There are two types of first-trimester screening: cell-free DNA (cfDNA) testing and combined first-trimester screening (AFP+BHCG).
Table of Contents
- What Is First Trimester Screening?
- How Is First Trimester Screening Done?
- When Is First Trimester Screening Performed?
- First Trimester Screening is between 10 and 12 weeks.
- First Trimester Screening is between 11 and 13 weeks.
- What are the advantages of First Trimester Screening for women?
- How Are the Results of First Trimester Screening Interpreted?
- How is it done?
What Is First Trimester Screening?
First-trimester screening (FTS) is a blood test that can be done between 10 and 13 weeks of pregnancy. It is used to screen for Down syndrome, Edwards syndrome, and other chromosomal abnormalities.
The FTS test measures the amount of two proteins in your blood, known as PAPP-A and hCG. PAPP-A increases during early pregnancy and hCG increases after implantation of the embryo into your uterus (womb). The results are combined with your age to produce a risk score (known as a Nuchal Translucency [NT] measurement) for detecting Down syndrome.
How Is First Trimester Screening Done?
- Blood test: This is a simple blood test that measures the level of certain proteins in your blood.
- Urine test: It’s similar to the blood test, but it uses urine instead of blood samples.
- Ultrasound: This can be done at any time during your pregnancy, but many doctors like to perform it during the first trimester as part of their routine checkups. Ultrasound can help determine whether there’s an ectopic pregnancy or other serious issues such as placenta previa (where the placenta partially or completely covers the cervix), placental abruption (when the placenta separates from its attachment site), and gestational diabetes, among others.
The combination of all three methods is often used by doctors to check for fetal abnormalities such as Down syndrome and neural tube defects (NTDs).
When Is First Trimester Screening Performed?
First-trimester screening is done between 10–13 weeks of pregnancy and helps to detect Down syndrome, Trisomy 18, and Trisomy 13. The mother’s blood sample is taken for this test.
First Trimester Screening is between 10 and 12 weeks.
First Trimester Screening is a blood test that can help you find out if your baby has Down syndrome or other chromosome problems.
In the UK, it’s called Nuchal Translucency (NT) screening. The sample of blood is taken from your arm by injecting a needle into a vein in your hand or arm. The results are available straight away and should be 100% accurate, but they need to be interpreted by a doctor because of the small number of abnormal tests that may occur.
First Trimester Screening is between 11 and 13 weeks.
The First Trimester Screening between 11 and 13 weeks is the most accurate time to do a screening test. If you are pregnant, you can wait until 13 weeks to do your test. The earlier testing is done, the less accurate it is (because there hasn’t been enough time for all of your baby’s cells to form yet).
If you have a normal result at this stage, then there’s nothing else that needs to be done until after your first-trimester screening results are available. The reason why we recommend getting their results before mid-pregnancy (16 weeks) is that if there was any problem with your baby’s development, we would continue monitoring them throughout pregnancy and postnatally too.
What are the advantages of First Trimester Screening for women?
First Trimester Screening is a safe and accurate screening test for Down’s syndrome, Edwards’ syndrome, and Patau’s syndrome. The advantages of First Trimester Screening are that it enables women to make an informed choice about their pregnancy at a time when they are feeling well and relaxed. It allows them to discuss with their doctor any concerns about the baby’s health before making a final decision on how they wish to proceed. Women may also wish to use this information to prepare psychologically for the birth of their baby, or indeed consider termination of pregnancy if they were not planning on having another child at this stage in their lives.
How Are the Results of First Trimester Screening Interpreted?
First Trimester Screening is a blood test that can detect Down syndrome and other chromosomal abnormalities in your baby. The results of First Trimester Screening are usually available within two weeks.
If the screening result is normal, you will receive a letter saying so. This means that there is less than a 1 in 250 chance that your baby has Down syndrome or another chromosomal abnormality (1/250). If the screening result is abnormal, you will receive a report with more information about what this means for you and your pregnancy.
How is it done?
First-trimester screening involves a blood test in the first trimester of pregnancy.
- The blood test is done between 10 and 12 weeks of pregnancy, between 11 and 13 weeks of pregnancy, or between 12 and 14 weeks of pregnancy.
- The exact timing depends on your healthcare provider’s preference.
First-trimester screening is a blood test that can help diagnose Down syndrome and other chromosomal conditions in the first trimester of pregnancy.
What are the benefits?
- It’s safe. The risk of miscarriage from first-trimester screening is less than 1%.
- It’s accurate. The chance of detecting Down syndrome with first-trimester screening is about 90%. This means that if you don’t have Down syndrome, there’s a 90% chance that your result will be negative. However, if you do have Down syndrome or another chromosome problem, there’s only about a 10% chance that your result will be falsely reassuring (also known as a “false negative”).
Getting a diagnosis of Down syndrome in the first trimester can be scary and overwhelming. However, with the help of your doctor and an experienced genetic counselor, you will be well prepared to make decisions about how to proceed in this situation. Remember that if you opt for more invasive testing such as chorionic villus sampling (CVS) or amniocentesis, there is still a risk of miscarriage even if your baby does not have Down syndrome.