New prenatal screening test could identify causes behind pregnancy complications

A revolutionary prenatal chromosome screening test could hold the key to helping expecting parents find causes behind ...
A revolutionary prenatal chromosome screening test could hold the key to helping expecting parents find causes behind serious pregnancy complications.  

A revolutionary prenatal chromosome screening test could hold the key to helping expecting parents find causes behind serious pregnancy complications including miscarriage and fetal death.

In the biggest study of its type in the world, researchers from the Victorian Clinical Genetics Services at the Murdoch Children's Research Institute and Illumina's Northern California Services Laboratory, examined the pregnancies of 90,000 women using cutting-edge prenatal screening.

Pregnant women can already access a non-invasive prenatal test, which offers a 99 per cent accuracy rate for detecting Down syndrome from 10-week gestation.

Historically, the method has screened only for the most common trisomies, a genetic disorder in which a person has three copies of a chromosome instead of two, focusing on about three to five particular chromosomes.

In a major medical breakthrough, the researchers expanded the scope of the traditional non-invasive prenatal blood test, screening up to 24 chromosomes and identifying rare genetic disorders.

"Expanding the non-invasive prenatal test to include all chromosomes can provide women with never before available information about the health of their pregnancy," said Dr Mark Pertile, Victorian Clinical Genetics Services head of reproductive genetics. 

"What the research found was missing or extra copies of these chromosomes can result in serious pregnancy complications including miscarriage, fetal growth restriction and spontaneous fetal death."

Dr Pertile said in some cases, only the placenta was affected by the rare trisomy and not the baby, but this could still cause serious problems for the normal development of the pregnancy. 

During pregnancy, small fragments of genetic material pass from the placenta into the mother's bloodstream.

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This genetic material can be tested using non-invasive prenatal testing to provide important information on the health of a pregnancy.

"This may help doctors in monitoring pregnancies at increased risk for complications such as fetal growth restriction and may also provide a reason for why some pregnancies have miscarried," Dr Pertile said.

"What we found anecdotally was that some patients were very grateful to find a reason why their pregnancies had miscarried."

He added doctors were also using the screening to identify chromosome conditions and monitor the functioning of the placenta to minimise the risks to mother and baby.

The Murdoch Children's Research Institute is the only centre in Australia that provides the advanced screening to about 15,000 women each year, but Dr Pertile hopes this will increase in the coming years. 

The research was undertaken at two clinical laboratories in Australia and the US.