Day and time of birth and mode of onset and birth
Studies of daily variations in numbers of births in England and Wales in the last three decades of the 20th century revealed a pronounced weekly cycle.
Numbers of births were lowest on Sundays, followed by Saturdays and numbers of births per day were highest from Tuesdays to Fridays. Numbers of births were also low on public holidays, with Christmas Day and Boxing Day having the lowest numbers of births in each year. Patterns were similar in other countries.
It was not possible to analyse births by the time of day of birth as in England and Wales time of birth was not included in national routine data systems until 2005. Local analyses from the mid-19th century onwards found that numbers of spontaneous births varied by time of day and were higher at night than during the day. It was expected that the rise in rates of obstetric intervention would affect overall patterns. Elective CS rates have been rising and these mainly take place on weekday mornings and the rationale for increasing rates of induction in the 1970s was to concentrate births into daytime hours.
This project produced the first national analyses of births by time of day and day of the week and mode of birth in England and Wales. As no national dataset contained all the data items needed, it was necessary to link data from birth registration and birth notification to data about care at birth. Data about over seven million births occurring in England and Wales from 2005 to 2014 were included (Macfarlane et al, in press).
The linked data were quality assured and used to analyse births and their outcomes by time of day, day of the year, of birth and mode of birth (Dattani and Macfarlane, 2018; Harper, 2018). As the linked data included confidential data items, the analyses were done in the secure environment of the Office for National Statistics’ Secure Research Service.
The overall numbers of births in England and Wales showed a regular weekly cycle with numbers increasing each day from Mondays to Fridays, and being lowest at weekends and on public holidays. Overall, numbers of births peaked in the mornings from 9am onwards and decreased after 5pm. Numbers increased again up to midnight and fell after 5am to 6am.
As data about care at birth differ between England and Wales, they were analysed separately. In England, spontaneous births after spontaneous onset of labour and spontaneous vaginal birth, including births in freestanding midwifery units and at home are more likely to occur between midnight and 6am, peaking by 4am to 6am than at other times of day. They are also slightly more likely on weekdays than at weekends and on public holidays. Elective CS births are concentrated onto weekday mornings. Births after induced labours are more likely to occur at hours around midnight on Tuesdays to Saturdays irrespective of the mode of birth (Martin et al, 2018).
Analyses of births in Wales were less detailed as numbers are lower and data about the onset of labour are not explicitly recorded, but these showed broadly similar patterns (Macfarlane et al, in press).
The overall conclusion is that the timing of births varies by place of birth, onset of labour and mode of birth and these patterns have implications for midwifery and medical staffing, particularly the finding that induced births peak around midnight rather than being concentrated during daytime hours. This research also shows the strength of data linkage in increasing the scope of routinely collected administrative data. Substantial amounts of work and time were needed to gain access to the data, to link and quality assure them and put them in a suitable format for analysis. This left insufficient time to assess any possible variations in outcome associated with the time of birth. A by-product of this project is a linked database, which can be used for other analyses of births and their outcome (Macfarlane et al, in press). Alison Macfarlane is professor of perinatal health at City, University of London
Martin P, Cortina-Borja M, Newburn M, Harper G, Gibson R, Dodwell M, Dattani N, Macfarlane A. (2018) Timing of singleton births by onset of labour and mode of birth in NHS maternity units in England, 2005-2014: a study of linked birth registration, birth notification, and hospital episode data. PLOS ONE 13(6): e0198183.
Dattani N, Macfarlane A. (2018) Linkage of Maternity Hospital Episode Statistics data to birth registration and notification records for births in England 2005-2014: methods. A population-based birth cohort study. BMJ Open 8(2): e017897.
Harper G. (2018) Linkage of Maternity Hospital Episode Statistics data to birth registration and notification records for births in England 2005–2014: Quality assurance of linkage of routine data for singleton and multiple births. BMJ Open 8 (3): e017898.
Macfarlane A, Dattani N, Gibson R, Harper G, Martin P, Dodwell M, Newburn M, Cortina-Borja M. (in press) Births and their outcomes by time, day and year: a retrospective birth cohort data linkage study. Health Services and Delivery Research.
Martin P, Mario Cortina-Borja M, Newburn M, Harper G, Gibson R, Dodwell M,Dattani N, Macfarlane A. (2018) Timing of singleton births by onset of labour and mode of birth in NHS maternity units in England, 2005- 2014: a study of linked birth registration, birth notification, and hospital episode data. PLoS ONE 13(6): e0198183.
‘Births and their outcome: analysing the daily, weekly and yearly cycle and their implications for the NHS’ was funded by the National Institute for Health Research. HS&DR Programme, project number HS&DR 12/136/93.
The views and opinions expressed here are those of the authors and do not necessarily reflect those of the HS&DR programme, NIHR, NHS or the Department of Health.
The data were processed in the secure environment of the Office for National Statistics’ Virtual Microdata Laboratory and the following disclaimer applies:
This work contains statistical data from ONS which is Crown Copyright. The use of the ONS statistical data in this work does not imply the endorsement of the ONS in relation to the interpretation or analysis of the statistical data. This work uses research datasets which may not exactly reproduce National Statistics aggregates.’