News & Events

Detecting fetal abnormalities in pregnancy

01 December 2011

A project funded by the EME programme will trial a new molecular test to detect chromosomal imbalances in foetuses found to have structural abnormalities on routine ultrasound screening.

All pregnant women are offered ultrasound scans at 12 and 20 weeks of pregnancy. One of the main aims of these scans is to detect fetal abnormalities, many of which are due to chromosome imbalances. Babies with chromosomal abnormalities have complex problems, usually resulting in developmental disability, and parents faced with this knowledge have to make difficult choices; some opt not to continue the pregnancy.

Testing for chromosome problems involves an 'invasive' procedure (e.g. amniocentesis) which can sometimes cause a miscarriage. Large chromosome imbalances require the baby's cells to be grown and examined using a microscope. This procedure (karyotyping) is slow and labour-intensive.

Array comparative genomic hybridisation (aCGH) is a new molecular test that can rapidly detect smaller (sub-microscopic) imbalances.

The study, led by Professor Stephen Robson, Professor of Fetal Medicine at Newcastle University, will recruit 1000 couples undergoing karyotyping because of a fetal abnormality picked up on a screening scan at the 11-14 or 18-21 weeks of pregnancy. Arrays will be performed and interpreted in six cytogenetics laboratories. The researchers aim to determine if aCGH detects harmful chromosomal imbalances more often and more quickly than karyotyping, and at less cost. In addition, the study will find out what parents, health professionals and commissioners think of the new technology.

Professor Stephen Robson commented; "We believe current evidence does not yet support the introduction of this technology into prenatal clinical practice. Without this knowledge it is not possible to either recommend an array platform for clinical use or provide robust evidence-based information to potential parents." He added; "We aim to provide guidance on whether aCGH should replace karyotyping in prenatal diagnosis of fetal anomalies detected by routine ultrasound screening."

Cases will be recruited from 11 fetal medicine centres across England & Wales (Southampton University and Kings College Hospitals, Royal Free, Royal London, Leeds, Liverpool, Cambridge, Newcastle, Bristol and Exeter).

View the project details