Estimating the birth prevalence and pregnancy outcomes of congenital malformations worldwide

Sowmiya Moorthie,C P Howson,Mary Petrou ,Ah Bittles ,Hanan Hamamy ,Jk Morris ,Lavínia Schüler‐Faccini ,Christopher Wren ,P A Mossey ,Sue Povey ,Pierpaolo Mastroiacovo ,Joy E Lawn ,Babak Khoshnood ,Hannah Blencowe,Bernadette Modell,Judith Rankin ,Stephen Gibbons ,Aj Neville ,Arnold L Christianson ,Simon Cousens ,Mw Darlison ,Ka Yunnis

doi:10.1007/s12687-018-0384-2

Abstract

Congenital anomaly registries have two main surveillance aims: firstly to define baseline epidemiology of important congenital anomalies to facilitate programme, policy and resource planning, and secondly to identify clusters of cases and any other epidemiological changes that could give early warning of environmental or infectious hazards. However, setting up a sustainable registry and surveillance system is resource-intensive requiring national infrastructure for recording all cases and diagnostic facilities to identify those malformations that that are not externally visible. Consequently, not all countries have yet established robust surveillance systems. For these countries, methods are needed to generate estimates of prevalence of these disorders which can act as a starting point for assessing disease burden and service implications. Here, we describe how registry data from high-income settings can be used for generating reference rates that can be used as provisional estimates for countries with little or no observational data on non-syndromic congenital malformations.

Highlights

The Modell Database of Congenital Disorders (MGDb) uses a set of defined methods to relate demographic data to known birth prevalence of selected groups of congenital disorders, in order to generate estimates relevant to public health, policymaking and clinical practice (Modell et al 2016; Moorthie et al 2017)
The existence of long-standing congenital anomaly registries has the advantage that high-quality population-based data on birth prevalence and pregnancy outcomes are readily available in settings with rigorous surveillance programmes, which provide information on congenital malformations
In this paper, which is the 5th in a supplement on the estimation of congenital disorders, we describe how data from the European Surveillance of Congenital Anomalies and Twins (EUROCAT) network can be used both to obtain countryspecific rates for birth prevalences and outcomes and to generate average European rates for use as reference rates for countries with little or no observational data on nonsyndromic congenital malformations

Summary

Introduction

The Modell Database of Congenital Disorders (MGDb) uses a set of defined methods to relate demographic data to known birth prevalence of selected groups of congenital disorders, in order to generate estimates relevant to public health, policymaking and clinical practice (Modell et al 2016; Moorthie et al 2017). There are limitations, with individual registries differing in case ascertainment due to a number of factors (e.g. resources, extent, amount of prenatal diagnosis available to women, number of data sources used and mode of access to records etc.) This is likely for outcomes that end in a foetal loss or termination of pregnancy and this may partially account for considerable differences between countries in reported rates. Ethnic and environmental factors affect the birth prevalence of some groups of non-syndromic malformations, including neural tube defects and orofacial clefts For these conditions, local or regional information on prevalence where available is preferable to EUROCAT averages, and EUROCAT and ICBDSR country-specific data has been used in MGDb (Kadir et al 2016). These estimates can be improved on and can be done so through direct contact with data sources such as EUROCAT to obtain more precise breakdowns

Conclusion

Findings

Compliance with ethical standards