Giving birth to a child is an outstanding experience, but it is also common to feel concerned about so many things that may affect the health and wellbeing of your baby. To ensure your baby is growing in a healthy way and doesn't have any chromosomal or genetic defects, you may consider going for first trimester screening. It is a non-invasive testing procedure and goes a long way in identifying any risks for the fetus to have certain defects. Keep reading to learn everything about first trimester screening and if you should really opt for it.
When Is First Trimester Screening and What Does It Detect?
This prenatal test offers information about a baby's risk of certain health related issues, including chromosomal conditions, such as Edwards’s syndrome and Down's syndrome. It starts with a blood test that measures the levels of human chorionic Gonadotropin (hCG) and pregnancy-associated plasma protein-A (PAPP-A). High levels of hCG or low levels of PAPP-A may indicate birth defects. It is followed by an ultrasound exam that measures the size of the clear space in the tissue at the back of your baby's neck. An increased thickness of this area may indicate Down syndrome.
You usually go for first trimester screening after you're 11 weeks pregnant – you can get the screening done as early as 9 weeks. The results of the ultrasound and the blood test combined with your age will help your healthcare provider make important decisions about your baby's health. This helps gauge your risk of carrying an abnormal baby. In case the risk is high, your healthcare provider may even order some other tests to make sure if there are any chromosomal defects in your baby.
How Is First Trimester Screening Performed?
During the blood test, your lab assistant will insert a needle into your vein in the arm and draw some blood that they will use for analysis. You can resume your normal activities immediately.
During your ultrasound exam, you will have to lie on your back on a large exam table with your legs opened. Your healthcare provider will then place a wand-like device in your vagina to transmit sound waves to gather the reflections. These waves will then be converted into digital images that will help measure the size of the back of the neck of your baby. The ultrasound exam won't hurt but it may take up to an hour or so. You usually get your test results within a week.
How to Understand the First Trimester Screening Results
You have to bear in mind that the first screening is exactly what it says – it's a screening test, not a diagnostic test. It only tells if a mother is at risk of carrying a baby with a chromosomal or genetic defect. In so many cases, an abnormal test report proves false after delivery.
You won't get any specific quantitative values for the separate parts of your first trimester screening. You will only be informed if your test results are normal or abnormal. Your genetic counselor will also specify a risk level considering your report.
You may have to go for additional testing if your test report shows "abnormal." Your genetic counselor will help identify the most relevant diagnostic tests, such as amniocentesis or CVS to make a proper diagnosis. Be sure to discuss all invasive procedures with your healthcare providers before opting for them. Also, learn about the pros and cons of undergoing these invasive procedures. This may require additional counseling.
Accuracy of First Trimester Screening
As mentioned, it is possible to get false positive results through your first trimester screening test. A positive result that shows you're at an increased risk of giving birth to a baby with genetic disorders doesn't mean your baby will definitely have a health problem. It just indicates you may consider going for other testing options for proper diagnosis.
For Down syndrome, the first trimester detection rates are as high as 85%. It means that screening tests cannot detect all possible cases of Down syndrome. It also implies that even if you have a negative screen result, you may still end up giving birth to a child with Down syndrome.
Are There Any Risks and Side Effects to the Mother or the Baby?
There isn't any risk involved in undergoing this procedure. You may just feel some discomfort when your healthcare provider draws blood. Keep in mind that there can be false positive rate for this screening test, so always consider the possibility of receiving abnormal results and then giving birth to healthy baby.
Does Everyone Need the First Trimester Screening?
No, that is not the case. It is up to you to decide if you really want to go for a screening test during your first trimester or not. You also need to consider what the test results would mean to you and how you would proceed with your pregnancy after that. Be sure to talk to a genetic counselor before you decide to go for a test. The counselor will explain the benefits and drawbacks of having the test, and may also share other important support resources that will help you make a decision about going for the test. Be sure to listen to him or her and know all your options before you finalize your decision.