‘Significant’ increase in rate of sudden infant death syndrome

The rate of sudden infant death syndrome (SIDS) in Ireland has “increased significantly” in recent years, states the latest National Paediatric Mortality Register (NPMR) report.

“The recent increase in SIDS rates may indicate reduced awareness, inconsistent adherence to safer sleep guidelines, or gaps in targeted prevention.”

Separately, preliminary findings from a HSE review of SIDS cases from 2002 to 2024 has identified a “stark” social gradient, with SIDS rates higher in disadvantaged communities.

SIDS is the sudden, unexpected death of an infant aged under one year, which appears to have occurred during sleep and remains unexplained after a thorough investigation, including a complete autopsy, review of the circumstances of death, and clinical history. Most cases of SIDS occur in the first six months of life.

The exact cause of SIDS remains unknown. However, research has recorded certain risk factors, including those relating to infant sleep position, sleep environment, and exposure to cigarette smoke during or after pregnancy (further information is available at mychild.ie and hse.ie. A HSE leaflet, ‘Safe sleep for your baby’, is available at healthpromotion.ie).

In the 1980s, SIDS deaths in Ireland averaged 140 annually (2.2 per 1,000 live births). Over recent decades, SIDS cases declined dramatically in tandem with risk reduction campaigns. This was followed by a slowdown in the rate of decline. However, between 2019 and 2023, the national rate steadily increased from 0.20 per 1,000 live births (12 deaths) to 0.46 per 1,000 live births (25 deaths). The 25 SIDS deaths in 2023 was the highest number recorded since 2008. The provisional rate for 2024 is 0.37 (19 deaths), according to the NPMR report. While this would mark a return to normal variation, it is above the mean, suggesting continued monitoring is needed to determine whether this represents “a temporary fluctuation or the start of a new trend”.

The report noted that SIDS has re-emerged as the leading cause of death in the post-neonatal period (ie, babies aged 29–364 days).

The increase in the SIDS rate is “one of the most important findings” from the report.

“This concerning trend is compounded by the lack of granular information on contributory risk factors such as sleep environment, parental smoking, and social vulnerability,” stated the NPMR report, which was published last month by the National Office of Clinical Audit (NOCA).

The data signals the need for “strengthened surveillance” and “renewed national prevention efforts”.

Delays in death registration make it harder to identify trends at an early stage, noted the NPMR report.

“The piloting and implementation of the NPMR child death notification process will allow for more rapid capture of infant death data.”

A national review of SIDS cases from 2002–2024 is being conducted by HSE Child Health Public Health. Consultant in Public Health Medicine Dr Fiona Cianci, who is undertaking the research with Specialist Registrar Dr John Gannon, presented preliminary findings at a recent NOCA webinar.

Dr Cianci said reports had been received from frontline public health nurses, who observed “an increase in cases in recent years”, especially in emergency accommodation settings.

While SIDS occurs across all socio-demographic groups, the HSE’s preliminary findings reflect international evidence that socio-economic inequality is a significant risk factor.

According to the HSE findings, SIDS occurred nearly five times more commonly in disadvantaged areas compared to affluent areas. It occurred eight times more commonly in emergency accommodation settings (ie, homeless accommodation and International Protection Accommodation Service) compared with national incidence.

The observed socio-economic disparities in SIDS were not explained by documented sleep practices alone, suggesting a role for broader, structural, and social determinants of health. The HSE said the findings should be interpreted with caution due to limitations in data and relatively low numbers involved.

Dr Cianci noted a significant level of missing data relating to risk factors, which is needed to fully characterise the national risk profile. She also referred to engagement with the Central Statistics Office to ensure every case is captured in the finalised review.

The review will include recommendations on enhanced and targeted public communications, healthcare professional training, and data reporting. Dr Cianci highlighted the need for child-centred standards in emergency accommodation, and systems that maximise systemic learning from child mortality cases. She said prevention is a shared responsibility across government.

A HSE spokesperson told the Medical Independent measures are being taken to enhance public communications on SIDS, including the development of a new graphic leaflet that will be translated into key languages.

Safer sleep advice will continue to be promoted through the mychild.ie campaign.