Whether you’re newly pregnant or planning a pregnancy, you might be wondering about prenatal testing. The good news is, advances in technology mean there are more options for early and more accurate screening. A simple blood draw can usually give you the information you are looking for from as early as nine weeks into the pregnancy.
“Not knowing the outcome of hereditary conditions until much further in the pregnancy – or even at the birth – can be incredibly stressful.”
Dr Johan Estellon,
Territory Manager, Natera
What is non-invasive prenatal testing?
Non-invasive prenatal testing (NIPT) is a simple blood test, taken from the mother during the pregnancy, that can screen for certain abnormalities in the baby’s chromosomes. Using this technique, it is possible to look for some of the most common chromosomal abnormalities, such as Down syndrome. With some NIPT tests it is possible to test for a wider range of conditions, for example 22q11.1 deletion syndrome, in which part of chromosome number 22 is missing. These conditions are less well-known than Down syndrome but may have important consequences for the baby’s health. Knowing about these and other conditions before birth can give parents and their healthcare team early information which can help with managing the pregnancy, birth, and ongoing care.
What are the benefits of testing?
Ultimately, preparation and reassurance are the main beneﬁts of these tests. Some conditions are difficult or even impossible to detect with traditional ultrasound scans, so earlier NIPT testing can help to answer many of the initial queries you may have.
For mothers carrying twins, the ability to distinguish whether twins are identical or not can impact the care plan your healthcare provider creates. Some NIPT tests can determine not only the likelihood but also identify the sex of each twin.
NIPT tests can check for Down syndrome and more
Although most babies are born healthy, parents often worry throughout the pregnancy. After NIPT, most women ﬁnd out that the chance for certain chromosome abnormalities can be less than 1 in 10,000. This low-probability result provides many parents with the reassurance that they are hoping for. Families that ﬁnd out that the chances of a chromosome abnormality are increased can choose to have a deﬁnitive test such as amniocentesis or chorionic villus sampling (CVS). If the baby is affected, they can learn about the condition and work with their provider to make a pregnancy care plan that is best for them.
NIPT vs traditional measures
Traditional prenatal screening tests don’t return results until after 11 weeks of pregnancy. Some NIPT tests can be done as early as nine weeks. High probability results from both traditional and NIPT screening tests need to be conﬁrmed by an invasive test. In cases where there is a high-probability result, having this information earlier in pregnancy gives the family the option to do an earlier invasive test for conﬁrmation, called chorionic villus sampling, or CVS.
A further advantage of NIPT over traditional prenatal screening is that it can detect more cases of Down syndrome, and that it is less likely to give false positive results. A false positive result is when a high-probability result is given when actually the fetus has normal chromosomes.
If a woman is carrying a baby with Down syndrome, the traditional combined ﬁrst trimester test will indicate a high probability 80 out of 100 times. NIPT will indicate a high probability over 98 out of 100 times, meaning that NIPT can detect a higher proportion of all of the cases of Down syndrome. It is important to know that a high-probability result doesn’t mean for sure that the baby has Down syndrome and should be conﬁrmed with a diagnostic procedure such as amniocentesis or CVS.
Can my healthcare professional advise?
Absolutely. From your GP to your midwife, trained professionals will be able to advise you about NIPT and whether it is the right choice for you. They will be able to offer more details about the tests involved and your existing risk factors.
Whatever questions you may have, qualiﬁed professionals will be able to tell you about the standard timeline for getting the answers you need and explain any non-invasive testing that may be offered.
Most importantly, if there are any concerning results after an NIPT, your healthcare professionals can arrange to talk you through the implications to help you to prepare in the best way possible.
Whether that’s getting ready for an adapted birth plan, or to help healthcare professionals to offer the best care after your baby is born, the information provided by the test and the sup-port from your healthcare team can help you to prepare. Whatever the outcome, genetic screening and prenatal testing may give you the answers to many of the questions you have.