| Pregnancy Check Hacks Risk To Newborn
According to the latest finding the UK's Institute of Child Health successfully trialed the test on more than 70 pregnant women. The researchers tested women at risk of having babies affected by X chromosome-linked disorders that usually only affect boys, such as Duchenne muscular dystrophy. They also tested women at risk of carrying girls with a condition called congenital adrenal hyperplasia (CAH), which causes the genitalia to develop abnormally.
The earlier determination of foetal sex, couple of weeks before it can be detected by ultrasound. CAH can be treated in the womb using steroids.
Currently, to carry out a prenatal genetic test, scientists
must obtain cells from the foetus, using either amniocentesis
or chorionic villus sampling (CVS). Both techniques
involve injecting a needle into the womb, which can
cause a miscarriage in up to 1% of cases. They also
cannot be carried out until at least 11 weeks into the
pregnancy.
In the latest study, the scientists worked on petite
amounts of 'free foetal DNA' found in the watery part
of the mother's blood. At the moment the practice is
limited to identification of genes which are only present
in the father and can be passed on to the foetus. This
includes the sex formative genes or the rhesus gene
when the father is rhesus positive and the mother rhesus
negative.
Research is ongoing to find ways of improving the extraction
of free foetal DNA so that more conditions can be diagnosed,
such as cystic fibrosis or thalassaemia.
Professor Henry Halliday, an obstetrician at Belfast's Royal Maternity Hospital, said the test could certainly be useful. "It permits for earlier determination of foetal sex than was earlier possible using either chorionic villus sampling or ultrasound.
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