Clinical and cost-effectiveness of detailed anomaly ultrasound screening in the first trimester: a mixed-methods study.

BACKGROUND

In the United Kingdom, pregnant women are offered two scans: at 11-14 and 18-20 weeks' gestation. Current guidance supports fetal anatomical screening at the second scan, but evidence suggests earlier detection is possible.

OBJECTIVES

To determine clinical and cost-effectiveness of a detailed two-dimensional ultrasound scan in the first trimester for detection of fetal anomalies, in addition to usual practice.

DESIGN

Systematic review and meta-analysis. Nationwide survey. Analysis of National Congenital Anomaly Disease Registry data. Consensus procedure. Prospective survey of parental opinions. Probabilistic decision-analytic model for cost-effectiveness. Value-of-information analysis.

SETTING

United Kingdom National Health Service.

PARTICIPANTS

Pregnant women and partners.

INTERVENTIONS

Detailed anomaly ultrasound at 11-14 weeks' gestation, in addition to usual practice.

MAIN OUTCOME MEASURES

Diagnostic accuracy, protocol development, health economic modelling and value-of-information analysis.

DATA SOURCES

MEDLINE (OvidSP), EMBASE (OvidSP), Science Citation Index and Conference Proceedings Citation Index-Science (Web of Science Core Collection); National Congenital Anomaly Disease Registry; European Congenital Anomalies Registry; Surveys of National Health Service Trusts; screening sonographers, midwives and doctors; and parents; National Schedule of National Health Service Costs (2019-20).

REVIEW METHODS

Systematic review and meta-analysis for diagnostic accuracy.

RESULTS

First-trimester ultrasound detects 93.3% (95% confidence interval 90.4% to 95.7%) of a pre-selected group of eight major anomalies with specificity of 99.99% (95% confidence interval 99.98% to 99.99%) and positive predictive value of 96.5% (95% confidence interval 93.3 to 98.8, 416,877 fetuses, 40 studies). For major cardiac anomalies, the respective data are 55.8% (95% confidence interval 45.9% to 65.5%), 99.98% (95% confidence interval 99.97% to 99.99%) and 94.85% (95% confidence interval 91.63% to 97.32%, 306,872 fetuses, 45 studies). Of NHS trusts surveyed, 77% currently perform first-trimester anatomy assessment, with evidence of inequity of care; earlier screening resulted in more diagnoses before 16 weeks' gestation. A consensus procedure ( = 172) developed an anatomical protocol and minimum targets for diagnosis. Parental survey ( = 1374) indicated that over 90% would opt for such screening. Modelling of singleton pregnancies undergoing earlier anomaly screening using two-dimensional ultrasound was associated with increased mean healthcare costs per woman (£11, 95% confidence interval £1 to £29) and maternal quality-adjusted life-years (0.002065, 95% confidence interval 0.000565 to 0.00358), an incremental cost per quality-adjusted life-year of £5270, with likelihood of being cost-effective at £20,000 per quality-adjusted life-year of over 95%. Additional modelling predicted reductions in infant healthcare costs and quality-adjusted life-years. Decision uncertainty was low. Value-of-information analysis of cost-effectiveness results showed no groups of parameters for which further research to reduce uncertainty would likely prove cost-effective.

LIMITATIONS

Study heterogeneity; the lack of a universal reference standard; simplifying assumptions relating to economic model structure; and estimation of some parameters are documented and justified. The rarity of the conditions made estimation of longer-term maternal and infant costs and quality-adjusted life-years challenging, resulting in likely under-estimation of healthcare costs.

CONCLUSIONS

With standardisation and training, first-trimester ultrasound screening for fetal anomalies is clinically effective with over 90% detection for eight major conditions and low false-positive rates. Decision uncertainty around implementation is low and a prospective study would not be an efficient investment. Adding first-trimester anomaly screening to the current screening likely represents a cost-effective use of resources and is acceptable to parents.

FUTURE WORK

Focus on developing an implementation framework to modify the current United Kingdom Fetal Anomaly Screening Programme.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018111781 and CRD42018112434.

FUNDING

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/19/10) and is published in full in ; Vol. 29, No. 22. See the NIHR Funding and Awards website for further award information.