Prevalence of multiple births by socio-economic status, region and calendar period

Pat Doyle, London School of Hygiene & Tropical Medicine

[Project number 30108]

The proportion of deliveries that result in twins or higher order births has increased dramatically over the past twenty years in E&W. This reflects both the increasing use of assisted conception and the trend of increasing numbers of deliveries to older mothers. Mortality and morbidity is higher in multiple, compared to singleton, births, and knowledge about trends and variation by region is important for health planning purposes.
AIM: The overall aim of this study is to examine the prevalence of multiplicity within births to LS members, and to examine variation by maternal age, socio-economic status, region, and time. This is a stand-alone project and is not part of a larger programme of work.
Research objectives:
1. To examine variation in multiplicity within births to LS members by maternal age, socio-economic status, and region
2. To examine multiplicity within births to LS members over time
3. To use the information on sex of babies within multiple deliveries to estimate the proportion of dizygous twins and triplets
4. To use the information from objective 4 to estimate the number of babies resulting for assisted conception by region

STUDY DESIGN: This is a descriptive reproductive epidemiology project

ANALYSIS: Analysis will by largely tabulation followed by descriptive statistics. Multivariate modelling will be performed where there are sufficient numbers of cases. The unit of analysis is offspring of LS members.