'Something that helped the whole picture': Experiences of parents offered rapid prenatal exome sequencing in routine clinical care in the English National Health Service

Implementation of a national rapid prenatal exome sequencing service in England: evaluation of service outcomes and factors associated with regional variation

Introduction

Prenatal exome sequencing (pES) can enhance genetic diagnosis of fetuses with structural anomalies and has recently been introduced as a national service in England. We aimed to examine service outcomes such as diagnostic yield (definite final diagnosis), referral rate, and sources of referral, and explore variation in outcomes of pES by individual or service level factors between 01 October 2021 and 30 June 2022.

Methods

pES testing results from the National Health Service laboratories performing testing were linked to National Congenital Anomaly and Rare Disease Registration Service data and the Maternity Services Data Set and descriptive statistics computed.

Results

There were 475,089 women who gave birth in England during the study period. The referral rate for pES was 8.6 (95% CI 7.8, 9.4) per 10,000 maternities. About 59% of those referred proceeded with pES testing and 35% of women who proceeded received a definite final diagnosis with a median turnaround time of 15 days. Of those who had pES testing, 64.6% had a live birth, 25.3% underwent termination of pregnancy (median gestational age at termination: 26 weeks), and 9.3% had a stillbirth. Among the 85 women who had a definite final diagnosis, 40% had a termination of pregnancy, 18% had a stillbirth, and 42% had a live birth. The corresponding figures among women without a definite final diagnosis were 18%, 5%, and 78%, respectively. Among women who had a termination of pregnancy, the median gestational age at final report was 24.9 weeks and 26.2 weeks at termination. Variation observed in some of the characteristics and outcomes between regional services were limited by small sample size.

Conclusion

This study showed that of those referred, pES testing provided a diagnosis for one in three pregnancies with a fetal anomaly across England during the study period when other tests had been non-informative. Women who opted for a termination of pregnancy underwent the procedure at relatively late gestations. Earlier referral for pES, streamlining pathways, and faster turnaround times may help results to be available at an earlier gestation to allow families more time to make decisions around continuing or terminating their pregnancy. The variation in service outcomes between regional services needs to be investigated further to understand the reasons for these differences.

Equity and timeliness as factors in the effectiveness of an ethical prenatal sequencing service: reflections from parents and professionals

Prenatal sequencing tests are being introduced into clinical practice in many developed countries. In part due to its greater ability to detect genetic variation, offering prenatal sequencing can present ethical challenges. Here we review ethical issues arising following the implementation of prenatal sequencing in the English National Health Service (NHS). We analysed semi structured interviews conducted with 48 parents offered prenatal sequencing and 63 health professionals involved in delivering the service to identify the ethical issues raised. Two main themes were identified: (1) Equity of access (including issues around eligibility criteria, laboratory analytical processes, awareness and education of clinicians, fear of litigation, geography, parental travel costs, and access to private healthcare), and (2) Timeliness and its impact on parental decision-making in pregnancy (in the context of the law around termination of pregnancy, decision-making in the absence of prenatal sequencing results, and the "importance" of prenatal sequencing results). Recognising both the practical and systemic ethical issues that arise out of delivering a national prenatal sequencing service is crucial. Although specific to the English context, many of the issues we identified are applicable to prenatal sequencing services more broadly. Education of health professionals and parents will help to mitigate some of these ethical issues.