'It has been a rollercoaster' - pregnant mother incorrectly told of fatal foetal abnormality in test
A pregnant mother of two has told how she received a test result indicating her unborn baby had a fatal foetal abnormality - only to discover it was the wrong diagnosis.
Kerry Fonseca, of Balgriffin, north Dublin, who is 23 weeks pregnant, said she was on holiday in her native South Africa in March when she went for a check-up and was told by a gynaecologist of his concern after looking at her scan.
She had a positive non-invasive prenatal test (NIPT) in March, indicating her baby was at risk of trisomy 18, also called Edward's syndrome, a chromosomal condition recognised as a fatal foetal abnormality.
"I then had a chorionic villus sampling (CVS) diagnostic test in the Rotunda Hospital in Dublin and it too came back positive."
However, she opted to have an amniocentesis three weeks later and it came back clear.
It showed that her unborn child does not have any abnormality.
"My baby is fine with no chromosomal abnormalities and I am now 23 weeks along," said Kerry, who has two older daughters.
A CVS test involves removing and testing a small sample of cells from the placenta.
It is offered where there is a high risk a baby could have a genetic or chromosomal condition.
There can be different genetic readings between cells in the placenta and the foetus.
The other diagnostic test is amniocentesis, which is carried out on the amniotic fluid.
Ms Fonseca said she has a rare condition known as confined placental mosaicism characterised by the discrepancy between the chromosomal and genetic make-up of the unborn baby and placenta.
Both the placenta and unborn baby normally have the same make-up.
But when there is a difference, this can distort test results for fatal foetal abnormalities.
Ms Fonseca said she is very grateful for the high standard of care which she got in the Rotunda and will be giving birth to her baby there.
"It has been a rollercoaster for us," she added.
She feels that screening tests are strongly promoted and women are told they have high levels of accuracy.
These are known as non-invasive prenatal testing (NIPT).
However, based on her experience, she advises women to have a thorough diagnostic assessment before making a final decision.
Doctors caution that screening tests are not perfect.
Some women will be told that they or their baby has a higher chance of having a health problem when they are clear.
Also, a few will be informed that their baby has a lower risk of having a health issue when they have a condition which is of concern.