Debunking the “Weekend Effect” – New Insights on Birth Timings and Baby Mortality

Discrediting the “Weekend Effect” – Fresh Insights into Infant Birth Timing and Mortality

A recent investigation has unveiled that contrary to prior assumptions, the vast majority of births in England between 2005 and 2014 that occurred outside of regular working hours did not exhibit a substantially heightened risk of neonatal death from oxygen deprivation (anoxia) or trauma. A mere 2% of births, specifically those necessitating emergency cesarean delivery without preceding labor, demonstrated a 1.5-fold increased risk during non-working hours. This equivocates to 46 infant fatalities over the span of a decade, implying that attention should pivot toward addressing this specific subgroup of births.

The study in question presents a thorough exploration of the various factors influencing the temporal aspect of births, signifying that for the vast majority of deliveries, being born beyond conventional working hours is comparably safe to being born within them.

Recent research spanning from 2005 to 2014 in England reveals that the elevated risk of infant mortality due to anoxia (deprivation of oxygen) or trauma during birth hours that differ from regular working hours is not statistically significant.

This counters the prevailing notion of a ‘weekend effect,’ which had been previously supported by research suggesting an augmented risk of infant mortality for babies born outside standard working hours or on weekends.

Conducted by City, University of London, the present study amalgamates a substantial corpus of health service data and official statistics, encompassing over six million births spanning a decade. This extensive dataset enabled researchers to meticulously analyze birth occurrences, including categorization based on labor initiation (spontaneous onset, induced onset, absence of labor), delivery type (spontaneous, cesarean, or assisted with forceps or ventouse), time of day, day of birth, and consideration of obstetric risk factors.

Significantly, the study excluded stillbirths (deaths before delivery) from its analysis. It is established that over 90 percent of stillbirths transpire prior to labor commencement, thereby minimizing the potential influence of birth-related care. In the majority of remaining instances, it remains uncertain whether stillbirths occurred before or during delivery.

It’s worth noting that a prior study encompassing 1.3 million births in England did include stillbirths and assessed the day of the week of birth, albeit not the time of day. This study concluded that the incidence of stillbirth, pregnancy-related deaths, or deaths within the initial week following birth was elevated on weekends.

In Scotland, a separate study evaluated over a million births, excluding stillbirths and incorporating the time of day into the analysis of deaths within the first month post-birth. This study concluded that death rates were higher outside of working hours during weekdays compared to working hours.

Nonetheless, neither of these earlier studies possessed the necessary scope to identify the minute subset of births exhibiting a heightened risk of infant mortality, as unveiled in the ongoing study focused on English births.

The current study determined that for two percent of births in England – specifically those requiring emergency cesarean delivery without prior labor – being born outside of regular working hours entailed a 1.5-fold increased risk of infant mortality due to anoxia or trauma compared to births occurring during working hours. Although the demise of a newborn is an uncommon event, this elevated relative risk translates to a low absolute risk, approximately amounting to 46 newborn fatalities over the ten-year examination period.

The study recommends, grounded in this evidence, that efforts to mitigate risk should concentrate on this smaller subset of emergency births, rather than categorizing all out-of-hours births as perilous. It further advises that future research should be directed toward comprehending the demographics of those undergoing emergency cesarean births devoid of preceding labor and determining aspects of pre-birth and post-birth care in both community and hospital settings that could avert critical incidents. Such facets of care might encompass prenatal monitoring or guidance on healthcare-seeking behaviors, especially for highly vulnerable mothers and infants.

The authors of the study acknowledge that their investigation does not encompass birth data from the years 2015 to the present. Nonetheless, as these data remain unlinked and unavailable, the analysis of this period, encompassing the potential impact of the exacerbated maternity services staffing crisis and the COVID-19 pandemic, falls beyond the scope of the ongoing study. The authors express their intent to secure funding for the acquisition and analysis of these data in a subsequent research endeavor.

Alison Macfarlane, the Principal Investigator of the study and a Professor of Perinatal Health at the Department of Midwifery and Radiography, City, University of London, commented, “These findings are highly reassuring and underscore the advantages of utilizing an expansive, interconnected dataset. They highlight the necessity to redirect attention from birth timing to the identification of this minute, highly vulnerable subset of women and the requisite measures to meet their specific needs.”

Reference: “Neonatal mortality in NHS maternity units by timing and mode of birth: a retrospective linked cohort study” by Lucy Carty, Christopher Grollman1, Rachel Plachcinski, Mario Cortina-Borja, and Alison Macfarlane, 13 June 2023, BMJ Open.
DOI: 10.1136/bmjopen-2022-067630

The funding for this study was provided by ECHR.

Frequently Asked Questions (FAQs) about Neonatal Mortality

More about Neonatal Mortality

• Neonatal Mortality Study: City, University of London
• Research Paper: Neonatal Mortality in NHS Maternity Units
• City, University of London Department of Midwifery and Radiography