Births and their outcomes by time, day and year: a retrospective birth cohort data linkage study

Abstract

BackgroundStudies of daily variations in the numbers of births in England and Wales since the 1970s have found a pronounced weekly cycle, with numbers of daily births being highest from Tuesdays to Fridays and lowest at weekends and on public holidays. Mortality appeared to be higher at weekends. As time of birth was not included in national data systems until 2005, there have been no previous analyses by time of day.ObjectivesTo link data from birth registration and birth notification to data about care during birth and any subsequent hospital admissions and to quality assure the linkage. To use the linked data to analyse births and their outcomes by time of day, day of the week and year of birth.DesignA retrospective birth cohort analysis of linked routine data.SettingEngland and Wales.Outcome measuresMortality of babies and mothers, and morbidity recorded at birth and any subsequent hospital admission.Population and data sourcesBirth registration and notification records of 7,013,804 births in 2005–14, already linked to subsequent death registration records for babies, children and women who died within 1 year of giving birth, were provided by the Office for National Statistics. Stillbirths and neonatal deaths data from confidential enquiries for 2005–9 were linked to the registration records. Data for England were linked to Hospital Episode Statistics (HES) and data for Wales were linked to the Patient Episode Database for Wales and the National Community Child Health Database.ResultsCross-sectional analysis of all births in England and Wales showed a regular weekly cycle. Numbers of births each day increased from Mondays to Fridays. Numbers were lowest at weekends and on public holidays. Overall, numbers of births peaked between 09.00 and 12.00, followed by a much smaller peak in the early afternoon and a decrease after 17.00. Numbers then increased from 20.00, peaking at around 03.00–05.00, before falling again after 06.00. Singleton births after spontaneous onset and birth, including births in freestanding midwifery units and at home, were most likely to occur between midnight and 06.00, peaking at 04.00–06.00. Elective caesarean births were concentrated in weekday mornings. Births after induced labours were more likely to occur at hours around midnight on Tuesdays to Saturdays, irrespective of the mode of birth.LimitationsThe project was delayed by data access and information technology infrastructure problems. Data from confidential enquiries were available only for 2005–9 and some HES variables were incomplete. There was insufficient time to analyse the mortality and morbidity outcomes.ConclusionsThe timing of birth varies by place of birth, onset of labour and mode of birth. These patterns have implications for midwifery and medical staffing.Future workAn application has now been submitted for funding to analyse the mortality outcomes and further funding will be sought to undertake the other outstanding analyses.FundingThis project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full inHealth Services and Delivery Research; Vol. 7, No. 18. See the NIHR Journals Library website for further project information.

Linkage of maternity hospital episode statistics birth records to birth registration and notification records for births in England 2005–2006: quality assurance of linkage

“…These tend to have more complex data, although similar algorithms were successfully used for the quality of assurance of the linkage of multiple births to mothers’ delivery records. 6 In addition, the algorithms used in this study were deterministic, rather than probabilistic. The latter can be more effective when dealing with complex records, such as those with a lot of missing data or coding errors.…”

“…Finally, we did not assess whether the quality of linkage for multiples is comparable with live, singleton, NHS hospital births although QA of the linkage of multiple births to mothers’ delivery records suggested that it was better than had been initially assumed. 6 …”

“…Full details of available variables, data cleaning procedures and preparation steps for the included datasets are described elsewhere. 6 Many key variables were available from both birth registration and birth notification. The preferred sources are summarised in the online supplemental table S2 .…”

“…The hospital trust variable was developed as part of a previous study. 6 To account for differences in rounding between hospitals, a birth weight of + or – 100 g was considered a match.…”

“…This was done by the data owner, the Health and Social Care Information Centre, now known as NHS Digital, as part of an earlier, larger study by City, University of London. 6 …”