Section 7 – What does a higher chance result from combined or quadruple screening mean?
If your test result showed you had a higher chance of having a baby with Down’s syndrome (T21) or a higher chance of having a baby with Edwards’ (T18) or Patau’s (T13) syndrome (that is, a chance of 1 in 2 to 1 in 150), your midwife or obstetrician will have explained your test result to you in detail, including your individual chance. Remember that the lower the number, the higher the chance. So, for example, 1 in 80 is a higher chance of having a baby with Down’s syndrome than 1 in 140.
Between 2% and 3% (two and three in 100) women who have the screening test have a result which shows they have a higher chance of having a baby with one of these conditions.
If you are having twins you will have had an in-depth discussion with an obstetrician or midwife before having your combined test. This is because the decisions are more complicated as there are many issues to consider. The discussion will have included information on the type of twins you are having and what that could mean in relation to the chances of either one or both babies having one of the conditions screened for.
As you have a higher chance result, your choices are:
- no further testing
- NIPT, or
- invasive testing.
No further testing
Some women will want to prepare themselves for the birth knowing that their baby or babies have a chromosomal condition, while others may decide not to continue with the pregnancy.
You can discuss whether or not you want to have a non-invasive prenatal test (NIPT) or an invasive procedure.
You may face some difficult decisions after an invasive procedure that you need to be aware of beforehand. If the invasive test (amniocentesis or CVS) shows that only one baby has the condition, the decision on whether to continue with the pregnancy can be very difficult. Ending the pregnancy for the baby with the condition could also cause a miscarriage of the other twin. Your obstetrician will discuss this with you in more detail.
