The DESiGN trial (DEtection of Small for Gestational age Neonate), evaluating the effect of the Growth Assessment Protocol (GAP): study protocol for a randomised controlled trial

Differences When Classifying Small for Gestational Age Preterm Infants According to the Growth Chart Applied

OBJECTIVE

 Consensus around the ideal chart to classify preterm babies is scant. It is particularly relevant in small for gestational age (SGA) infants due to its clinical and therapeutic implications. The aim of the study was to compare Olsen, Intergrowth-21st, and Fenton growth charts, regarding the classification at birth and incidence of SGA preterm infants.

STUDY DESIGN

 Retrospective study of 529 preterm infants ≤ 32 weeks of gestational age. Birth weight Z-score was calculated applying the three growth charts and ponderal index (PI) was also estimated. Incidence of SGA (birth weight < 10th percentile) and clinical outcome were compared according to the chart used.

RESULTS

 Incidence of SGA was significantly higher (p < 0.001) with Olsen (101 cases, 19.1%) compared with Intergrowth-21st (75 cases, 14.2%) and Fenton (53 cases, 10%). Differences were also found with PI of SGA preterm infants, as those infants classified by Olsen were mostly symmetric (PI > 10th percentile), while Fenton and Intergrowth-21st identified less symmetric SGA infants. Kappa concordance between Intergrowth-21st and Fenton was 0.805, Intergrowth-21st versus Olsen 0.824, and Fenton versus Olsen 0.641. No differences were observed on neonatal morbidities or mortality.

CONCLUSION

 Significant differences were detected when classifying very preterm infants at birth according to the growth chart, mainly among symmetric SGA. Concordance between Fenton and Olsen was poor, but Intergrowth-21st showed high concordance with Fenton and Olsen. However, further research is needed to select the ideal chart. Variability in the population selected to create the curves and the accuracy dating the pregnancy are factors that may have explained differences.

KEY POINTS

· Very preterm infants are differently classified at birth with various growth charts.. · Higher incidence of small for gestational age infants with Olsen compared with Fenton or Intergrowth.. · Variability in population selection and accuracy in dating pregnancy may have explained differences..

Social inequalities in the risk of giving birth to a small for gestational age child in Sweden 2010-16: a cross-sectional study adopting an intersectional approach

BACKGROUND

Well-established associations exist between the risk of small for gestational age (SGA) and unidimensional sociodemographic factors. We investigated social inequalities in SGA risk and adopted an intersectional approach that simultaneously considers different social categories. By doing so, we could assess heterogeneities in SGA risk within unidimensional sociodemographic categories.

METHODS

We included all live 679 694 singleton births in Sweden between 2010 and 2016. The outcome was SGA, and the exposures were age, maternal educational level, dichotomous migration status and civil status. Thirty-six possible combinations of these factors constituted the exposure in an intersectional model. We present odds ratios (ORs) with 95% confidence intervals (95% CIs) and the area under the receiver operating characteristic curve (AUC)-a measurement of discriminatory accuracy (i.e. the ability to discriminate the babies born SGA from those who are not).

RESULTS

Women with low education and women born outside Sweden had ORs of 1.46 (95% CI 1.38-1.54) and 1.50 (95% CI 1.43-1.56) in unidimensional analyses, respectively. Among women aged under 25 with low education who were born outside Sweden and unmarried, the highest OR was 3.06 (2.59-3.63). The discriminatory accuracy was low for both the unidimensional model that included all sociodemographic factors (AUC 0. 563) and the intersectional model (AUC 0.571).

CONCLUSIONS

The intersectional approach revealed a complex sociodemographic pattern of SGA risk. Sociodemographic factors have a low accuracy in identifying SGA at the individual level, even when quantifying their multi-dimensional intersections. This cautions against interventions targeted to individuals belonging to socially defined groups to reduce social inequalities in SGA risk.

Characteristics associated with antenatally unidentified small-for-gestational-age fetuses: prospective cohort study nested within DESiGN randomized controlled trial

OBJECTIVE

To identify the clinical characteristics and patterns of ultrasound use amongst pregnancies with an antenatally unidentified small-for-gestational-age (SGA) fetus, compared with those in which SGA is identified, to understand how to design interventions that improve antenatal SGA identification.

METHODS

This was a prospective cohort study of singleton, non-anomalous SGA (birth weight < 10th centile) neonates born after 24 + 0 gestational weeks at 13 UK sites, recruited for the baseline period and control arm of the DESiGN trial. Pregnancy with antenatally unidentified SGA was defined if there was no scan or if the final scan showed estimated fetal weight (EFW) at the 10th centile or above. Identified SGA was defined if EFW was below the 10th centile at the last scan. Maternal and fetal sociodemographic and clinical characteristics were studied for associations with unidentified SGA using unadjusted and adjusted logistic regression models. Ultrasound parameters (gestational age at first growth scan, number and frequency of ultrasound scans) were described, stratified by presence of indication for serial ultrasound. Associations of unidentified SGA with absolute centile and percentage weight difference between the last scan and birth were also studied on unadjusted and adjusted logistic regression, according to time between the last scan and birth.

RESULTS

Of the 15 784 SGA babies included, SGA was not identified antenatally in 78.7% of cases. Of pregnancies with unidentified SGA, 47.1% had no recorded growth scan. Amongst 9410 pregnancies with complete data on key maternal comorbidities and antenatal complications, the risk of unidentified SGA was lower for women with any indication for serial scans (adjusted odds ratio (aOR), 0.56 (95% CI, 0.49-0.64)), for Asian compared with white women (aOR, 0.80 (95% CI, 0.69-0.93)) and for those with non-cephalic presentation at birth (aOR, 0.58 (95% CI, 0.46-0.73)). The risk of unidentified SGA was highest among women with a body mass index (BMI) of 25.0-29.9 kg/m2 (aOR, 1.15 (95% CI, 1.01-1.32)) and lowest in those with underweight BMI (aOR, 0.61 (95% CI, 0.48-0.76)) compared to women with BMI of 18.5-24.9 kg/m2 . Compared to women with identified SGA, those with unidentified SGA had fetuses of higher SGA birth-weight centile (adjusted odds for unidentified SGA increased by 1.21 (95% CI, 1.18-1.23) per one-centile increase between the 0th and 10th centiles). Duration between the last scan and birth increased with advancing gestation in pregnancies with unidentified SGA. SGA babies born within a week of the last growth scan had a mean difference between EFW and birth-weight centiles of 19.5 (SD, 13.8) centiles for the unidentified-SGA group and 0.2 (SD, 3.3) centiles for the identified-SGA group (adjusted mean difference between groups, 19.0 (95% CI, 17.8-20.1) centiles).

CONCLUSIONS

Unidentified SGA was more common amongst women without an indication for serial ultrasound, and in those with cephalic presentation at birth, BMI of 25.0-29.9 kg/m2 and less severe SGA. Ultrasound EFW was overestimated in women with unidentified SGA. This demonstrates the importance of improving the accuracy of SGA screening strategies in low-risk populations and continuing performance of ultrasound scans for term pregnancies. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Implementation of Uterine Artery Doppler Scanning: Improving the Care of Women and Babies High Risk for Fetal Growth Restriction

Introduction

While stillbirth rates have declined in many countries, these declines are less marked in the UK. Fetal growth restriction (FGR) affects about 3% to 7% of all pregnancies and is by far the single strongest risk factor for stillbirth. FGR implies a pathological restriction of the genetic growth potential and is not synonymous with small-for-gestational age (SGA). The Royal College of Obstetricians and Gynaecologists (RCOG) defines SGA as an estimated fetal weight (EFW) or abdominal circumference (AC) less than the 10th centile. The likelihood of FGR is higher in severe SGA defined as an EFW or AC less than the 3rd centile. The second version of Saving Babies' Lives Care Bundle (SBLCBv2) recommends the second trimester uterine artery Doppler (UtAD) pulsatility index (PI) screening for pregnancies at high risk of FGR. This study was aimed at determining the prevalence of FGR and assess pregnancy outcomes following the implementation of UtAD at the United Lincolnshire Hospitals NHS Trust (ULHT).

Methods

One-year retrospective cohort study (1st September 2020-31st August 2021) was conducted across both ULHT hospitals in the UK (Lincoln County Hospital in Lincoln and Pilgrim Hospital in Boston).

Results

During the study period, 5197 women were booked at ULHT. Of 5197, 349 were identified as high risk for FGR. When numbers were compared for the two hospitals, FGR rate was higher in Lincoln 8.10% vs. 4.51% in Boston. In addition, an increased proportion of abnormal UtAD scans was observed in Lincoln (35.7%) vs. in Boston (22%) (P = 0.014). Of the 349 UtAD scans, 237 were normal (67.9%), 41 showed unilateral notching (11.7%), 43 bilateral notching (12.3%), and 28 raised PI (8%). Babies in the bilateral notching group exhibited the lowest birth weight (P = 0.005), born at an earlier gestation (P = 0.029), and with low Apgar scores at 1 (P = 0.007) and 5 minutes (P < 0.001). Discussion. UtAD is a useful second trimester screening tool for women identified as high risk for FGR and helps stratify the intensity of surveillance. However, the findings call into question a focus solely on the UtAD PI for improving FGR detection without taking into account bilateral notching.

Improving antenatal detection of small-for-gestational-age fetus: economic evaluation of Growth Assessment Protocol

OBJECTIVE

To determine whether the Growth Assessment Protocol (GAP), as implemented in the DESiGN trial, is cost-effective in terms of antenatal detection of small-for-gestational-age (SGA) neonate, when compared with standard care.

METHODS

This was an incremental cost-effectiveness analysis undertaken from the perspective of a UK National Health Service hospital provider. Thirteen maternity units from England, UK, were recruited to the DESiGN (DEtection of Small for GestatioNal age fetus) trial, a cluster randomized controlled trial. Singleton, non-anomalous pregnancies which delivered after 24 + 0 gestational weeks between November 2015 and February 2019 were analyzed. Probabilistic decision modeling using clinical trial data was undertaken. The main outcomes of the study were the expected incremental cost, the additional number of SGA neonates identified antenatally and the incremental cost-effectiveness ratio (ICER) (cost per additional SGA neonate identified) of implementing GAP. Secondary analysis focused on the ICER per infant quality-adjusted life year (QALY) gained.

RESULTS

The expected incremental cost (including hospital care and implementation costs) of GAP over standard care was £34 559 per 1000 births, with a 68% probability that implementation of GAP would be associated with increased costs to sustain program delivery. GAP identified an additional 1.77 SGA neonates per 1000 births (55% probability of it being more clinically effective). The ICER for GAP was £19 525 per additional SGA neonate identified, with a 44% probability that GAP would both increase cost and identify more SGA neonates compared with standard care. The probability of GAP being the dominant clinical strategy was low (11%). The expected incremental cost per infant QALY gained ranged from £68 242 to £545 940, depending on assumptions regarding the QALY value of detection of SGA.

CONCLUSION

The economic case for replacing standard care with GAP is weak based on the analysis reported in our study. However, this conclusion should be viewed taking into account that cost-effectiveness analyses are always limited by the assumptions made. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Effect of the Growth Assessment Protocol on the DEtection of Small for GestatioNal age fetus: process evaluation from the DESiGN cluster randomised trial

Background

Reducing the rate of stillbirth is an international priority. At least half of babies stillborn in high-income countries are small for gestational-age (SGA). The Growth Assessment Protocol (GAP), a complex antenatal intervention that aims to increase the rate of antenatal detection of SGA, was evaluated in the DESiGN type 2 hybrid effectiveness-implementation cluster randomised trial (n = 13 clusters). In this paper, we present the trial process evaluation.

Methods

A mixed-methods process evaluation was conducted. Clinical leads and frontline healthcare professionals were interviewed to inform understanding of context (implementing and standard care sites) and GAP implementation (implementing sites). Thematic analysis of interview text used the context and implementation of complex interventions framework to understand acceptability, feasibility, and the impact of context. A review of implementing cluster clinical guidelines, training and maternity records was conducted to assess fidelity, dose and reach.

Results

Interviews were conducted with 28 clinical leads and 27 frontline healthcare professionals across 11 sites. Staff at implementing sites generally found GAP to be acceptable but raised issues of feasibility, caused by conflicting demands on resource, and variable beliefs among clinical leaders regarding the intervention value. GAP was implemented with variable fidelity (concordance of local guidelines to GAP was high at two sites, moderate at two and low at one site), all sites achieved the target to train > 75% staff using face-to-face methods, but only one site trained > 75% staff using e-learning methods; a median of 84% (range 78–87%) of women were correctly risk stratified at the five implementing sites. Most sites achieved high scores for reach (median 94%, range 62–98% of women had a customised growth chart), but generally, low scores for dose (median 31%, range 8–53% of low-risk women and median 5%, range 0–17% of high-risk women) were monitored for SGA as recommended.

Conclusions

Implementation of GAP was generally acceptable to staff but with issues of feasibility that are likely to have contributed to variation in implementation strength. Leadership and resourcing are fundamental to effective implementation of clinical service changes, even when such changes are well aligned to policy mandated service-change priorities.

Trial registration

Primary registry and trial identifying number: ISRCTN 67698474. Registered 02/11/16. 10.1186/ISRCTN67698474.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13012-022-01228-1.

Evaluating the Growth Assessment Protocol for stillbirth prevention: progress and challenges

Many stillbirths are associated with fetal growth restriction, and are hence potentially avoidable. The Growth Assessment Protocol (GAP) is a multidisciplinary program with an evidence based care pathway, training in risk assessment, fetal growth surveillance with customised charts and rolling audit. Antenatal detection of small for gestational age (SGA) has become an indicator of quality of care. Evaluation is essential to understand the impact of such a prevention program. Randomised trials will not be effective if they cannot ensure proper implementation before assessment. Observational studies have allowed realistic evaluation in practice, with other factors excluded that may have influenced the outcome. An award winning 10 year study of stillbirth data in England has been able to assess the effect of GAP in isolation, and found a strong, causal association with improved antenatal detection of SGA babies, and the sustained decline in national stillbirth rates. The challenge now is to apply this program more widely in low and middle income settings where the main global burden of stillbirth is, and to adapt it to local needs and resources.

Evaluation of the Growth Assessment Protocol (GAP) for antenatal detection of small for gestational age: The DESiGN cluster randomised trial

BACKGROUND

Antenatal detection and management of small for gestational age (SGA) is a strategy to reduce stillbirth. Large observational studies provide conflicting results on the effect of the Growth Assessment Protocol (GAP) in relation to detection of SGA and reduction of stillbirth; to the best of our knowledge, there are no reported randomised control trials. Our aim was to determine if GAP improves antenatal detection of SGA compared to standard care.

METHODS AND FINDINGS

This was a pragmatic, superiority, 2-arm, parallel group, open, cluster randomised control trial. Maternity units in England were eligible to participate in the study, except if they had already implemented GAP. All women who gave birth in participating clusters (maternity units) during the year prior to randomisation and during the trial (November 2016 to February 2019) were included. Multiple pregnancies, fetal abnormalities or births before 24+1 weeks were excluded. Clusters were randomised to immediate implementation of GAP, an antenatal care package aimed at improving detection of SGA as a means to reduce the rate of stillbirth, or to standard care. Randomisation by random permutation was stratified by time of study inclusion and cluster size. Data were obtained from hospital electronic records for 12 months prerandomisation, the washout period (interval between randomisation and data collection of outcomes), and the outcome period (last 6 months of the study). The primary outcome was ultrasound detection of SGA (estimated fetal weight <10th centile using customised centiles (intervention) or Hadlock centiles (standard care)) confirmed at birth (birthweight <10th centile by both customised and population centiles). Secondary outcomes were maternal and neonatal outcomes, including induction of labour, gestational age at delivery, mode of birth, neonatal morbidity, and stillbirth/perinatal mortality. A 2-stage cluster-summary statistical approach calculated the absolute difference (intervention minus standard care arm) adjusted using the prerandomisation estimate, maternal age, ethnicity, parity, and randomisation strata. Intervention arm clusters that made no attempt to implement GAP were excluded in modified intention to treat (mITT) analysis; full ITT was also reported. Process evaluation assessed implementation fidelity, reach, dose, acceptability, and feasibility. Seven clusters were randomised to GAP and 6 to standard care. Following exclusions, there were 11,096 births exposed to the intervention (5 clusters) and 13,810 exposed to standard care (6 clusters) during the outcome period (mITT analysis). Age, height, and weight were broadly similar between arms, but there were fewer women: of white ethnicity (56.2% versus 62.7%), and in the least deprived quintile of the Index of Multiple Deprivation (7.5% versus 16.5%) in the intervention arm during the outcome period. Antenatal detection of SGA was 25.9% in the intervention and 27.7% in the standard care arm (adjusted difference 2.2%, 95% confidence interval (CI) -6.4% to 10.7%; p = 0.62). Findings were consistent in full ITT analysis. Fidelity and dose of GAP implementation were variable, while a high proportion (88.7%) of women were reached. Use of routinely collected data is both a strength (cost-efficient) and a limitation (occurrence of missing data); the modest number of clusters limits our ability to study small effect sizes.

CONCLUSIONS

In this study, we observed no effect of GAP on antenatal detection of SGA compared to standard care. Given variable implementation observed, future studies should incorporate standardised implementation outcomes such as those reported here to determine generalisability of our findings.

TRIAL REGISTRATION

This trial is registered with the ISRCTN registry, ISRCTN67698474.

Fetal growth restriction: underdiagnosed condition with non-optimal screening

BACKGROUND

Fetal Growth restriction (FGR) is the pathological failure of a fetus to reach its biologically determined growth potential. Detection of FGR fetuses is a universally agreed key objective of antenatal care. Antenatal detection of FGR has undeniable benefits, juggling between intensive fetal surveillance and optimized timing of delivery; it reduces adverse perinatal outcomes by up to four-fold. However, FGR is still widely underdiagnosed. We aimed to identify the prevalence of FGR diagnosis in our wards and study the impact of the 2013 published French guidelines on the detection rate of FGR. The secondary objective aimed to highlight the factors of suboptimal screening in the population of non-diagnosed FGR fetuses and emphasize the screening method that led to antenatal diagnosis of FGR.

MATERIALS AND METHODS

We conducted a retrospective study at a single tertiary maternity center in Lyon-France, the Femme Mère Enfant Hospital, including the exhaustive population of FGR born after 24 + 0 weeks of gestation from 1 January 2011 to 31 December 2017. FGR was defined combining the neonatal and antenatal consensus-based definitions for early and late FGR in absence of congenital anomalies, excluding small for gestational age fetuses. For all FGR fetuses, we compared the antenatal detection rate of FGR during 2011-2013 to 2015-2017, since the French guidelines were published in December 2013. When FGR fetuses underwent an antenatal diagnosis of FGR, we retrospectively collected the characteristics that led to the diagnosis. When fetuses were not diagnosed as FGR, we retrospectively reviewed the implementation of the recommended screening method, enabling to evaluate whether screening was optimal or not. Statistical analysis was performed in July 2018, and statistical significance was regarded as a p-value <.05.

RESULTS

Over the seven-year period, and among 31,052 newborns, 1020 (3.3%) infants were identified as FGR and met the inclusion criteria. The detection rate of FGR was similar before and after publication of the French Guidelines related to FGR in 2013. Indeed, 50.8% (201/395) FGR were diagnosed between 2011 and 2013 versus 52.6% (245/465) between 2015 and 2017 (p = .59). In the population of non-diagnosed FGR infants, screening was suboptimal in 80%. Symphysis-fundal height (SFH) was not measured in 10.7%, with no difference before and after 2014 (7.3 versus 11.8% p = .11). Ultrasound examination for fetal biometry had not been prescribed in spite of abnormal SFH in 47.7% of undiagnosed FGR infants. Diagnosis has been missed in 11.5% of infants because of misinterpretation of the estimated fetal weight's centile.

CONCLUSION

FGR is widely underdiagnosed. However, the limited performances can partially be explained by the regular misuse of screening method in clinical practice. Despite the systematic third trimester ultrasound screening, the detection rate of FGR was similar to the one reported in the medical literature. The timing of routine third trimester ultrasound in low-risk women may be rethought.

Stillbirth rates, service outcomes and costs of implementing NHS England's Saving Babies' Lives care bundle in maternity units in England: A cohort study

Objective

To assess implementation of the Saving Babies Lives (SBL) Care Bundle, a collection of practice recommendations in four key areas, to reduce stillbirth in England.

Design

A retrospective cohort study of 463,630 births in 19 NHS Trusts in England using routinely collected electronic data supplemented with case note audit (n = 1,658), and surveys of service users (n = 2,085) and health care professionals (n = 1,064). The primary outcome was stillbirth rate. Outcome rates two years before and after the nominal SBL implementation date were derived as a measure of change over the implementation period. Data were collected on secondary outcomes and process outcomes which reflected implementation of the SBL care bundle.

Results

The total stillbirth rate, declined from 4.2 to 3.4 per 1,000 births between the two time points (adjusted Relative Risk (aRR) 0.80, 95% Confidence Interval (95% CI) 0.70 to 0.91, P<0.001). There was a contemporaneous increase in induction of labour (aRR 1.20 (95%CI 1.18–1.21), p<0.001) and emergency Caesarean section (aRR 1.10 (95%CI 1.07–1.12), p<0.001). The number of ultrasound scans performed (aRR 1.25 (95%CI 1.21–1.28), p<0.001) and the proportion of small for gestational age infants detected (aRR 1.59 (95%CI 1.32–1.92), p<0.001) also increased. Organisations reporting higher levels of implementation had improvements in process measures in all elements of the care bundle. An economic analysis estimated the cost of implementing the care bundle at ~£140 per birth. However, neither the costs nor changes in outcomes could be definitively attributed to implementation of the SBL care bundle.

Conclusions

Implementation of the SBL care bundle increased over time in the majority of sites. Implementation was associated with improvements in process outcomes. The reduction in stillbirth rates in participating sites exceeded that reported nationally in the same timeframe. The intervention should be refined to identify women who are most likely to benefit and minimise unwarranted intervention.

Trial registration

The study was registered on (NCT03231007); www.clinicaltrials.gov.

Using electronic patient records to assess the effect of a complex antenatal intervention in a cluster randomised controlled trial-data management experience from the DESiGN Trial team

BACKGROUND

The use of electronic patient records for assessing outcomes in clinical trials is a methodological strategy intended to drive faster and more cost-efficient acquisition of results. The aim of this manuscript was to outline the data collection and management considerations of a maternity and perinatal clinical trial using data from electronic patient records, exemplifying the DESiGN Trial as a case study.

METHODS

The DESiGN Trial is a cluster randomised control trial assessing the effect of a complex intervention versus standard care for identifying small for gestational age foetuses. Data on maternal/perinatal characteristics and outcomes including infants admitted to neonatal care, parameters from foetal ultrasound and details of hospital activity for health-economic evaluation were collected at two time points from four types of electronic patient records held in 22 different electronic record systems at the 13 research clusters. Data were pseudonymised on site using a bespoke Microsoft Excel macro and securely transferred to the central data store. Data quality checks were undertaken. Rules for data harmonisation of the raw data were developed and a data dictionary produced, along with rules and assumptions for data linkage of the datasets. The dictionary included descriptions of the rationale and assumptions for data harmonisation and quality checks.

RESULTS

Data were collected on 182,052 babies from 178,350 pregnancies in 165,397 unique women. Data availability and completeness varied across research sites; each of eight variables which were key to calculation of the primary outcome were completely missing in median 3 (range 1-4) clusters at the time of the first data download. This improved by the second data download following clarification of instructions to the research sites (each of the eight key variables were completely missing in median 1 (range 0-1) cluster at the second time point). Common data management challenges were harmonising a single variable from multiple sources and categorising free-text data, solutions were developed for this trial.

CONCLUSIONS

Conduct of clinical trials which use electronic patient records for the assessment of outcomes can be time and cost-effective but still requires appropriate time and resources to maximise data quality. A difficulty for pregnancy and perinatal research in the UK is the wide variety of different systems used to collect patient data across maternity units. In this manuscript, we describe how we managed this and provide a detailed data dictionary covering the harmonisation of variable names and values that will be helpful for other researchers working with these data.

TRIAL REGISTRATION

Primary registry and trial identifying number: ISRCTN 67698474 . Registered on 02/11/16.

Costing the impact of interventions during pregnancy in the UK: a systematic review of economic evaluations

OBJECTIVE

The aim of this review was to summarise the current evidence on the costing of resource use within UK maternity care, in order to facilitate the estimation of incremental resource and cost impacts potentially attributable to maternity care interventions.

METHODS

A systematic review of economic evaluations was conducted by searching Medline, the Health Management Information Consortium, the National Health Service (NHS) Economic Evaluations Database, CINAHL and National Institute for Health and Care Excellence (NICE) guidelines for economic evaluations within UK maternity care, published between January 2010 and August 2019 in the English language. Unit costs for healthcare activities provided to women within the antenatal, intrapartum and postnatal period were inflated to 2018-2019 prices. Assessment of study quality was performed using the Quality of Health Economic Analyses checklist.

RESULTS

Of 5084 titles or full texts screened, 37 papers were included in the final review (27 primary research articles, 7 review articles and 3 economic evaluations from NICE guidelines). Of the 27 primary research articles, 21 were scored as high quality, 3 as medium quality and 3 were low quality. Variation was noted in cost estimates for healthcare activities throughout the maternity care pathway: for midwife-led outpatient appointment, the range was £27.34-£146.25 (mean £81.78), emergency caesarean section, range was £1056.44-£4982.21 (mean £3508.93) and postnatal admission, range was £103.00-£870.10 per day (mean £469.55).

CONCLUSIONS

Wide variation exists in costs applied to maternity healthcare activities, resulting in challenges in attributing cost to maternity activities. The level of variation in cost calculations is likely to reflect the uncertainty within the system and must be dealt with by conducting sensitivity analyses. Nationally agreed prices for granular unit costs are needed to standardise cost-effectiveness evaluations of new interventions within maternity care, to be used either for research purposes or decisions regarding national intervention uptake.

PROSPERO REGISTRATION NUMBER

CRD42019145309.