The website www.mybabycompany.co.uk, seen in April 2019, promoted a Non Invasive Prenatal Test. Under the heading “SENSITIVITY”, text stated “The test is reliable even at a low fetal fraction (FF>2%) with an incidence of false positives <0.1%.” The FAQs featured the question “How accurate is the PrenatalSafe 5 test” with the answer “The PrenatalSafe 5 test is accurate and identifies Down’s syndrome, Edwards’ syndrome and Patau’s syndrome in over 99% of cases”. A further question stated “What are my options if I have a high risk result for trisomy?” alongside the answer “If you get a “high risk” result, you will need to contact your consultant or midwife. The next steps will be determined in consultation with your healthcare provider. All high risk results should be confirmed by a follow-up invasive procedure, such as amniocentesis or Chorionic Villus Sampling (CVS).”
The ASA challenged whether the ad misleadingly exaggerated the accuracy with which the treatment could detect whether a foetus would have the referenced genetic conditions.
My Baby Enterprises Ltd t/a www.mybabycompany.co.uk provided a response from their test provider which contained two studies that showed the NIPT test had a false positive rate of less than 0.1% was able to identify Down’s syndrome, Edwards’ syndrome and Patau’s syndrome in over 99% of cases. They said their online leaflet showed the various Positive Predictive Values (PPV) of NIPT for different conditions, which ranged from 99% to 59%. They said that PPV’s can vary depending on the sample set taken and the prevalence of the cohort used, and therefore PPV’s are only a guide in terms of how confident the clinician and patient can feel about a given result; it does not directly relate to the individual patient.
The ASA considered that consumers were likely to understand from the claims “The PrenatalSafe 5 test is accurate and identifies Down’s syndrome, Edwards’ syndrome and Patau’s syndrome in over 99% of cases” to mean that that there was a 99% chance that a foetus would ultimately have those conditions following a NIPT “positive result”. We understood that the detection rate figure represented the proportion of foetuses that NIPT had identified to have the relevant condition out of all foetuses which ultimately had the condition. However, that figure did not give any insight into the proportion of positive results where the foetus would ultimately not have the condition. As such, while we understood that the detection rate was clinically useful for other reasons, we considered that its prominent use in the ad was likely to mislead consumers about how often the foetus would actually have the condition after receiving a “positive” NIPT result. We noted the test supplier claimed that their test had a Positive Predictive Value (PPV) that ranged from 59% to 99% for the different conditions, which meant that out of all the foetuses with “positive” results, 59% to 99% would ultimately have the relevant condition. We understood that in any circumstance where a positive result was given, further invasive tests would be required in order to confirm that one way or the other. Notwithstanding that, we understood that the PPV results were based on a study that involved a selected sample of women who already had a high chance of having a foetus with a genetic anomaly as opposed to a sample of women from the general population, which was likely produce a higher PPV than in the general population. We considered that it was insufficient to rely on the study alone as the basis for the claimed PPVs. We noted that a systematic review of the performance of NIPT based on 41 studies found that in a general population, the PPV was 81.6% for Down’s Syndrome, 37% for Edwards’ Syndrome and 49% for Patau’s Syndrome. We considered that the detection rates in the ad were therefore likely to mislead consumers regarding the accuracy of a positive NIPT result. Because consumers were likely to understand from the ad that the detection rate signified the likelihood that the foetus would have the relevant condition in the event of a “positive result”, when that was not the case, we concluded that the ad was misleading. The ad breached CAP Code (Edition 12) rule 3.1, 3.3 (Misleading advertising), 3.9 and 3.10 (Qualification).
The ad must not appear again in its current form. We told mybabycompany.co.uk to avoid using the detection rate figure or alternatively, if referencing the detection rate, to quote robust Positive Predictive Values (based on adequate evidence) alongside an accompanying explanation of both figures.