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Pregnancy Care Guidelines

52 Other considerations in testing for fetal chromosomal anomalies

52.1 Availability and uptake of testing

The range of tests available, policies for testing and uptake by women vary regionally (O’Leary et al 2006). Overall, approximately 50% of pregnant women participated in nuchal translucency ultrasound in 2007–08 (Nisbet et al 2010). A Victorian study found the uptake of combined first trimester screening to be 70–80% in recent years (Hui et al 2016).

Studies in Victoria and Queensland have shown higher uptake of testing in metropolitan areas and in private health care and lower rates of diagnosis of Down syndrome in urban areas and public health care (Muggli et al 2006; Coory et al 2007). Lower rates of access to testing in rural areas may reflect lack of transport, low levels of support and income in these areas and women’s attitudes. However, it has been suggested that low uptake of testing among women from low socioeconomic groups reflects lower rates of informed choice rather than women’s attitudes (Dormandy et al 2005).

A West Australian study found the lowest uptake of testing was among women who were Aboriginal (14.9%), living in remote areas (38.0%), under the age of 25 (40.2%), in the lowest socioeconomic group (41.6%) and with three or more children (48.4%). Logistic regression analysis showed all socio-demographic factors to be strongly associated with screening behaviour, with adjustment for ethnicity, socio-economic status, age, parity and area of residence (Maxwell et al 2011).

A study into testing for chromosomal anomalies among Aboriginal and Torres Strait Islander women (MSHR 2010) has highlighted the importance of providing information about testing and identified challenges involved in offering testing, particularly in remote areas. These included late presentation in pregnancy, difficulties establishing accurate gestational age, limited consultation time to discuss the testing process, competing priorities in antenatal care, confusion about what needs to be done and when, and organisational logistics (eg women’s travel, where to send blood, referral procedures).

Recommendation

  • Practice point
  • FFF

Support all women to access testing for chromosomal anomalies in a timely manner.

Approved by NHMRC in December 2011; expires December 2016

52.2 Health professional education

Health professionals caring for pregnant women should undertake continuing education regarding testing for probability of chromosomal anomalies and be aware of current tests available and the settings in which they can be implemented (RANZCOG 2015). This includes education about:

  • the conditions being tested for, life outcomes, lived experiences of families and individuals with the condition and supports available for families and individuals with the condition
  • delivery of ‘challenging news’ rather than ‘bad news’ with respect to chromosomal conditions.

52.3 Accreditation of ultrasound operators

The ability to achieve a reliable measurement of nuchal translucency depends on appropriate training and adherence to a standard technique to achieve uniformity of results among different operators (Nicolaides 2004). Accreditation of ultrasound operators to conduct nuchal translucency measurement should be through the Nuchal Translucency – Ultrasound, Education and Monitoring Program administered through RANZCOG.

52.4 Quality assurance

All laboratories used for testing must be accredited by the National Association of Testing Authorities (NATA). External and internal quality control measures should be in place.

References

  • Coory MD, Roselli T, Carroll HJ (2007) Antenatal care implications of population-based trends in Down syndrome birth rates by rurality and antenatal care provider, Queensland, 1990–2004. Med J Aust 186(5): 230–34.
  • Dormandy E, Michie S, Hooper R et al (2005) Low uptake of prenatal screening for Down syndrome in minority ethnic groups and socially deprived groups: A reflection of women’s attitudes or a failure to facilitate informed choices? Int J Epidemiol 34 (2): 346–52.
  • Hui L, Muggli EE, Halliday JL (2016) Population-based trends in prenatal screening and diagnosis for aneuploidy: a retrospective analysis of 38 years of state-wide data. BJOG 123(1): 90-7.
  • Maxwell S, Brameld K, Bower C et al (2011) Socio-demographic disparities in the uptake of prenatal screening and diagnosis in Western Australia. Aust N Z J Obstet Gynaecol 51(1): 9-16.
  • MSHR (2010) Screening for Fetal Anomalies: Views of Indigenous People and their Health Care Providers. Darwin: Menzies School of Health Research.
  • Muggli EE, McCloskey D, Halliday JL (2006) Health behaviour modelling for prenatal diagnosis in Australia: a geodemographic framework for health service utilisation and policy development. BMC Health Serv Res 6(1): 109.
  • Nicolaides KH (2004) Nuchal translucency and other first-trimester sonographic markers of chromosomal abnormalities. Am J Obstet Gynecol 191: 45–67.
  • Nisbet DL, Robertson AC, Schluter PJ et al (2010) Auditing ultrasound assessment of fetal nuchal translucency thickness: A review of Australian national data 2002–2008. Aust NZ J Obstet Gynaecol 50: 450–55.
  • O’Leary P, Breheny N, Reid G et al (2006) Regional variations in prenatal screening across Australia: stepping towards a national policy framework. Aust NZ J Obstet Gynaecol 46: 427–32.
  • RANZCOG (2015) Prenatal Screening and Diagnosis of Chromosomal and Genetic Abnormalities in the Fetus in Pregnancy C-Obs 59. Melbourne: Royal Australian and New Zealand College of Obstetricians and Gynaecologists.
Last updated: 
11 September 2018