Research on non-invasive prenatal testing
Last Reviewed 28/07/2016
RAPID is a large programme of research to develop non-invasive prenatal testing (NIPT) for the NHS. Traditional pre-natal testing requires a sample to be taken by invasive procedures, such as amniocentesis, which have a risk of miscarriage. NIPT uses a normal blood sample taken from the arm of a pregnant woman. In some circumstances ultrasound is used for pre-natal testing, but NIPT can be used earlier in pregnancy.
The project is funded by the NIHR and run by Professor Lyn Chitty. Along with laboratory research into the technologies of NIPT, it is important to capture the views of women and their partners (and clinicians) so that the NHS can offer NIPT in the most appropriate and sensitive way.
The following studies into the views of women, their partners and clinicians were carried out (or contributed to) by Genetic Alliance UK. They asked about the use of NIPT for sex determination, Down syndrome diagnosis, and the diagnosis of single gene disorders. The studies found an overwhelmingly positive response to the use of NIPT.
Views and experiences of patients using NIPT for fetal sex determination
Prenatal fetal sex determination is offered to women who are “at risk” of having a child with a serious genetic disorder if that disorder affects only boys or only girls. Ultrasound has been the traditional method used, but NIPT can be used earlier in pregnancy. This study assessed the views and experiences of people who had used NIPT for fetal sex determination. A total of 44
people (38 women and 6 partners) were interviewed. Participants’ views and experiences were overwhelmingly positive. The advantages that interviewees reported included: avoiding miscarriage (when compared with invasive methods), and several benefits arising from earlier testing, such as a feeling of being more in control, a feeling of “normalisation” of pregnancy and peace of mind. Some disadvantages were discussed. These included concerns about the potential use of NIPT to identify sex for social reasons, and increased bonding (due to knowing the baby’s sex) at a time in pregnancy when ‘natural’ miscarriage risk is high. However, participants felt these were fairly minor in comparison with the advantages of NIPT.1
Views of the public towards the use of NIPT for Down syndrome
Currently pregnant women are offered screening for Down syndrome, which is non-invasive but does not give a diagnosis. Women whose screening result shows that their pregnancy is ‘high risk’ for Down syndrome are then offered a test based on an invasive procedure such as amniocentesis, with its risk of miscarriage. Interviews were carried out with 40 pregnant women to discover their views on using NIPT for Down syndrome. The overwhelming majority of women viewed it as a positive advancement in prenatal care, highlighting the numerous practical and psychological advantages of a safe test that is highly accurate and could be conducted early in pregnancy. Concerns were raised that testing could become ‘routine’ with women possibly not at first appreciating that the test result might be a diagnosis of Down syndrome. There were also concerns that women might feel under pressure to use the test because it needs only a simple blood sample. The impact on how disabled people feel, and possible stigma for women who decline testing, were also noted. Nevertheless, the vast majority of women said they would be likely to use NIPT, including half of the women who currently decline screening. Women expressed a preference for counselling (before and after taking the test) to be delivered by a midwife.2
The views and likely uptake of NIPT for Down syndrome were also investigated with a survey, completed by women from two antenatal clinics, users of the Mumsnet website and users of the Facebook page and website of the charity Antenatal Results and Choices (ARC). Again, the vast majority thought NIPT for Down syndrome was a positive development, with 88.2% saying they would use the test (including those who would currently decline screening). The most important feature of the test for a large majority of women was the lack of risk of miscarriage. When asked about what they would do if the test found Down syndrome, 30.7% said they were “likely” to terminate the pregnancy and 36.5% were “unlikely” to terminate.3
Views and experiences of women who had used NIPT for single gene disorders
This study used interviews to explore women’s experiences of using NIPT for a number of single gene disorders. They had been offered NIPT because they were “at risk” of having a child with a single gene disorder (such as achondroplasia, and Apert syndrome). The women were positive about NIPT, being an accurate, safe, and early test. It reduced the period of uncertainty and worry by being carried out within the first trimester. It took away the risk of miscarriage for those women who would otherwise have chosen to have an invasive test. Some women would not have risked invasive testing, so for these women NIPT enabled them to have an early diagnostic test that was more accurate than ultrasound. Where ultrasound abnormalities had been detected, NIPT ended the ‘diagnostic odyssey’, so that women could make practical and psychological preparations for the birth. Women felt that the most appropriate way for NIPT to be delivered would be through specialist health services.4
Views of health professionals towards NIPT for single gene disorders
The aim of this study was to determine health professional opinions, in order to help design services for its delivery. Focus groups and interviews were carried out with health professionals from a range of backgrounds, who were all involved in caring for carriers of single gene disorders. The health professionals were very positive about NIPT, describing benefits arising from the lack of a risk of miscarriage, earlier testing and a simple procedure. A number of concerns were raised about delivering the test in reality. Participants emphasized the need for the new test to be highly accurate and validated. There was concern that people may not give as much thought to having a blood test compared to an invasive test or that it may be viewed as routine. As such there was concern that NIPT may affect informed consent. In addition there was concern that the simplicity of a blood test may lead women to feel pressure to take test, and pressure to terminate affected pregnancies. However, the health professionals felt these concerns could be overcome with good counselling before and after the test. To ensure high quality care, the health professionals felt that NIPT should be offered through genetics or other specialist services. Ongoing education and training of health professionals will be important, and guidelines and regulation are needed for effective delivery of NIPT. 5
- Lewis et al 2012. European Journal of Human Genetics. Non-invasive prenatal diagnosis for fetal sex determination: benefits and disadvantages from the service users’ perspective.
- Lewis et al 2013. Public Health Genomics. Non-invasive prenatal testing for Down’s syndrome: pregnant women’s views and likely uptake.
- Lewis et al 2014. British Journal of Obstetrics and Gynaecology. Non-invasive prenatal testing for trisomy 21: a cross-sectional survey of service users’ views and likely uptake.
- Lewis et al 2013. Clinical Genetics. Non-invasive prenatal diagnosis for single gene disorders: experience of patients.
- Hill et al 2012. American Journal of Medical Genetics. Views and preferences for the implementation of non-invasive prenatal diagnosis for single gene disorders from health professionals in the United Kingdom.