Imagine this scenario: In a remote, resource-limited area, a premature infant is fighting for survival, while you, as a healthcare worker, lack essential warming equipment. Every year, millions of newborns die globally, with the majority of these deaths occurring in low-income countries, particularly in sub-Saharan Africa and South Asia. Hypothermia, an invisible killer, threatens these fragile lives daily. The critical question is: How can we provide the most effective warming solutions for these vulnerable infants in resource-constrained environments?

This article explores evidence-based strategies for selecting and using neonatal warming devices in low-resource settings, offering clear and practical guidance for healthcare providers and policymakers to reduce mortality and morbidity caused by hypothermia.

Globally, approximately 2.4 million newborns die annually, with 80% of these deaths occurring in sub-Saharan Africa and South Asia. Nearly all cases (99%) are concentrated in low- and middle-income countries. Hypothermia has emerged as a leading cause of neonatal mortality and illness, particularly in areas with limited medical resources. Premature infants, due to their physiological vulnerabilities, are at higher risk of hypothermia, which is associated with up to 80% of preterm deaths. Newborns, especially those with low birth weight, have limited ability to regulate their body temperature and rely on external support to maintain warmth.

The World Health Organization (WHO) recommends kangaroo mother care (skin-to-skin contact) as an effective warming method for preterm or low-birth-weight infants. However, this approach is not universally applicable. In cases of shock, resuscitation, or mechanical ventilation, skin-to-skin contact may be impractical. Moreover, for unstable infants, data on the safety and efficacy of this method remain limited. Cultural practices, parental health, or logistical constraints may also hinder continuous skin-to-skin care. Even when recommended for 24-hour use, uninterrupted implementation is often challenging.

For unstable newborns or those unable to receive skin-to-skin care, warming devices are indispensable. WHO guidelines suggest using radiant warmers or incubators for unstable infants weighing under 2000 grams or stable infants of the same weight when skin-to-skin care is unavailable. Yet, in low-resource regions, these devices are often inaccessible—either broken, lacking spare parts, or rendered unusable due to power shortages or missing supplies.

To assist healthcare workers and policymakers in making informed decisions, this article evaluates the effectiveness, availability, and cost-efficiency of various neonatal warming devices. The focus is on identifying optimal warming solutions when skin-to-skin care is not an option.

A "rapid review" approach was used to synthesize existing evidence efficiently. Key steps included:

• Systematic searches for reviews, randomized trials, and quasi-randomized trials to assess device efficacy.
• Guideline analysis for recommendations tailored to low-resource settings.
• Technical specifications review to evaluate device feasibility in resource-limited environments.

All searches were completed in May 2022, with cross-verified data extraction. The study protocol was registered on OSF.

The review revealed scarce evidence on optimal warming methods for unstable or non-skin-to-skin newborns. Most studies were small, conducted in high-income countries, and focused on infants older than seven days without complications. Guideline recommendations were often based on older protocols with weak evidence.

Despite these limitations, the analysis concluded that radiant warmers, incubators, and conductive heating mattresses show comparable warming efficacy.

• Radiant Warmers: Allow rapid access during resuscitation (needed for ~10% of births) but may increase insensible water loss, requiring careful fluid management for preterm infants.
• Incubators: Humidity control benefits extremely preterm infants (<1500g) in their first two weeks but are often only viable in advanced neonatal units with skilled staff.
• Conductive Heating Mattresses: Cost-effective, energy-efficient, and equally effective per Gray and Flenady’s review. Phase-change material (PCM) mattresses extend functionality for transport but require preheating and are less suitable for critically ill newborns needing rapid rewarming.

When choosing a device, weigh these factors:

• Need for rapid patient access
• Rewarming requirements
• Water loss minimization
• Infant characteristics (weight, gestational age, stability)
• Institutional resources (staffing, finances)
• Technical demands (power, space, safety)

Total ownership costs—including purchase, maintenance, training, and disposal—must also be assessed. Incubators typically incur higher costs than radiant warmers or mattresses.

This review guides healthcare providers and policymakers in selecting warming devices for unstable or non-skin-to-skin newborns in low-resource settings. No single solution fits all; each facility must align choices with patient needs and local constraints. Key takeaways:

• Skin-to-skin care remains first-line for stable infants.
• Radiant warmers excel in delivery rooms for resuscitation.
• Heating mattresses offer cost-effective, low-power solutions for neonatal units.
• Incubators are vital for extremely preterm infants in referral centers.

Future innovations should prioritize safety, energy efficiency, and affordability. More randomized trials are needed to evaluate devices for unstable newborns in low-resource contexts.