Miranda Dodwell

Estimating intrapartum‐related perinatal mortality rates for booked home births: when the ‘best’ available data are not good enough

Objective  To critically appraise a recent study on the safety of home birth (Mori R, Dougherty M, Whittle M. BJOG 2008;115:554) and assess its contribution to the debate about risks and benefits of planned home birth for women at low risk of complications.

Mapping midwifery and obstetric units in England

OBJECTIVE to describe the configuration of midwifery units, both alongside&free-standing, and obstetric units in England. DESIGN national survey amongst Heads of Midwifery in English Maternity Services SETTING: National Health Service (NHS) in England PARTICIPANTS: English Maternity Services Measurements descriptive statistics of Alongside Midwifery Units and Free-standing Midwifery Units and Obstetric Units and their annual births/year in English Maternity Services FINDINGS: alongside midwifery units have nearly doubled since 2010 (n = 53-97); free-standing midwifery units have increased slightly (n = 58-61). There has been a significant reduction in maternity services without either an alongside or free-standing midwifery unit (75-32). The percentage of all births in midwifery units has trebled, now representing 14% of all births in England. This masks significant differences in percentage of all births in midwifery units between different maternity services with a spread of 4% to 31%. KEY CONCLUSIONS In some areas of England, women have no access to a local midwifery unit, despite the National Institute for Health&Clinical Excellence (NICE) recommending them as an important place of birth option for low risk women. The numbers of midwifery units have increased significantly in England since 2010 but this growth is almost exclusively in alongside midwifery units. The percentage of women giving birth in midwifery units varies significantly between maternity services suggesting that many midwifery units are underutilised. IMPLICATIONS FOR PRACTICE Both the availability and utilisation of midwifery units in England could be improved.

Findings of meta-analysis cannot be relied on

Mayor reports that a meta-analysis has linked planned home births with a twofold higher rate of neonatal mortality compared with hospital births.1 2 Closer inspection calls this finding into question. The quality of studies in any meta-analysis is critical, but no assessment was reported. Studies were observational with many not matched adequately for confounders. Neonatal …

An estimation of intrapartum-related perinatal mortality rates for booked home births in England and Wales between 1994 and 2003

Sir, Mori et al.1 in their study of intrapartum-related perinatal mortality (IPPM) attempted to use the ‘best available data’ to ascertain the safety of planned home birth. The validity of this study hinges on being able to determine accurately the numbers of planned home births. The authors took the number of actual home births and adjusted these using estimates for the numbers of both unintended home births and transfers. However, they have used inappropriate assumptions and have compounded these mistakes by making errors in their calculations. The authors use two ways to determine the numbers of unintended/unplanned home births, Calculation A and Calculation B, producing widely differing answers of 66 265 and 20 206. ‘Calculation A’ estimates unintended home births as a percentage of all home births (50.7%) and ‘Calculation B’ as a percentage of overall births (0.32%). There is no reason to suppose that the number of unplanned home births are affected by a rise or fall in planned home births. However, it is likely that a small consistent proportion of pregnant women concealed their pregnancy or had a precipitate birth at home. Indeed, Murphy et al.2 reported from 1970 to 1979 that unintended home births formed a relatively constant percentage of all births, around 0.35% (range 0.27–0.46%). In contrast, unintended home births increased from 17 to 57% when expressed as a percentage of all home births. This demonstrates that Calculation B is more reliable, yet Mori’s conclusions are based on Calculation A. In addition, calculations of the numbers of births and IPPM rates using Calculation A are subjected to a number of errors and are therefore invalid. The Murphy study2 data applicable to Calculation A are included in table 1 (34.1%) but omitted from the calculation of both the weighted mean and the sensitivity ranges used to create table 2. Using a revised weighted mean and lower range reduces the IPPM in table 2 for booked home birth, whether completed or not, and increases the range in which the true rates could lie. Furthermore, the study by Redshaw et al.3 is included in Calculation B, but not Calculation A, adding to the inaccuracy of table 2. There is also an error in table 2 in the completed home birth group, where 31 intrapartum-related deaths for 83 343–111 126 gives a range of 0.28–0.37, not 0.28–1.15 as reported. The authors inappropriately make a direct comparison between women who ‘planned home birth but transferred to hospital’, with ‘all women giving birth’. However, if such a comparison is made, it should be with a matched group of women who booked hospital birth and developed complications. The key finding that ‘there was no evidence of difference in the IPPM rate for the booked home birth group compared to the overall rate’ was not reported in the abstract as it should have been. DOI: 10.1111/j.1471-0528.2008.01835.x www.blackwellpublishing.com/bjog Correspondence

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

Background Maternity care has to be available 24 hours a day, seven days a week. It is known that obstetric intervention can influence the time of birth, but no previous analysis at a national level in England has yet investigated in detail the ways in which the day and time of birth varies by onset of labour and mode of giving birth. Method We linked data from birth registration, birth notification, and Maternity Hospital Episode Statistics and analysed 5,093,615 singleton births in NHS maternity units in England from 2005 to 2014. We used descriptive statistics and negative binomial regression models with harmonic terms to establish how patterns of timing of birth vary by onset of labour, mode of giving birth and gestational age. Results The timing of birth by time of day and day of the week varies considerably by onset of labour and mode of birth. Spontaneous births after spontaneous onset are more likely to occur between midnight and 6am than at other times of day, and are also slightly more likely on weekdays than at weekends and on public holidays. Elective caesarean births are concentrated onto weekday mornings. Births after induced labours are more likely to occur at hours around midnight on Tuesdays to Saturdays and on days before a public holiday period, than on Sundays, Mondays and during or just after a public holiday. Conclusion The timing of births varies by onset of labour and mode of birth and these patterns have implications for midwifery and medical staffing. Further research is needed to understand the processes behind these findings.