Correcting misunderstandings
‘I’m young, so I don’t need to have any tests for Down syndrome’
Although younger women are at lower risk than older women, many babies with Down syndrome are still conceived by women who would not be defined as at increased risk due to their age (ie 35 or 37 years and above). Screening tests should be offered to women of all ages. Diagnostic testing can follow if requested.
‘The tests were all OK, so my baby is normal’
Tests during pregnancy can detect increased risk or presence of certain conditions only. No test, or combination of tests, will detect all birth defects or medical conditions.
‘My blood test was normal, so my baby doesn’t have Down syndrome’
Blood/screening tests cannot detect all pregnancies with Down syndrome. A woman with a ‘normal’ (low risk) screening test result does have a chance of having a baby with Down syndrome but this risk is not high enough for diagnostic testing to be indicated.
‘The blood test says there’s something wrong with my baby’
Blood/screening tests during pregnancy do not detect birth defects; they indicate which pregnancies have an increased risk of certain genetic conditions and birth defects. Most fetuses with ‘abnormal’ (increased risk) test results do not have Down syndrome. This is an indication for referral for diagnostic procedures.
‘The blood test says there is something wrong so I need a diagnostic test’
If the blood/screening test was second trimester maternal serum screening, increased risk results are due to inaccurate dates (if LMP only given) in 30% of cases. Check dates by ultrasound. An increased risk result on a screening test is an indication for diagnostic testing; however, a small number of women choose not to have diagnostic testing.
‘If I have another screening test, I might get a better result’
Screening tests are most accurate when done at the correct time in the pregnancy. Retesting is only performed if dates are inaccurate. It is strongly recommended not to have both first and second trimester screening tests (see above, ‘Frequently asked questions’).
‘I am over 35 years so I need to have a CVS or amniocentesis’
Women aged 35 years and over (or 37 years in Victoria) at EDD may choose to have a diagnostic test, may prefer the option of screening tests, or may choose to have no tests at all. Women in this age group should be aware that they are more likely to have an increased risk result from a screening test as age is part of the risk calculation, in which case they will then need to consider diagnostic testing.
‘It’s not worth having any tests because I wouldn’t terminate the pregnancy’
Some people feel it is beneficial to know if the fetus has an anomaly to prepare for the birth and future. Others prefer to wait until delivery. All women should have the opportunity to consider testing.