To determine the effects of heated and humidified inspiratory gas through heated humidifiers (HHs) compared to non-heated and non-humidified inspiratory gas on mortality and morbidity in neonates receiving respiratory support during resuscitation immediately after birth and after the initial resuscitation.

Comparison 1: Heated and humidified inspiratory gas through heated humidifiers (HHs) compared to non-heated and non-humidified inspiratory gas on mortality and morbidity in neonates receiving respiratory support during resuscitation immediately after birth.

Proposed subgroup analyses:

• Gestational age: < 30 weeks, 30-36 weeks, 37 weeks and over;
• Mode of respiratory support (e.g. mask continuous positive airway pressure, mask intermittent positive pressure ventilation, endotracheal intermittent positive pressure ventilation).

Comparison 2: Heated and humidified inspiratory gas through heated humidifiers (HHs) compared to non-heated and non-humidified inspiratory gas on mortality and morbidity in neonates receiving respiratory support after initial resuscitation.

Proposed subgroup analyses:

• Gestational age: < 30 weeks, 30-36 weeks, 37 weeks and over;
• Mode of respiratory support (e.g. low flow oxygen, high flow nasal cannula, nasal continuous positive airway pressure, nasal intermittent positive pressure ventilation, conventional mechanical ventilation, high frequency ventilation).
• Sites of intervention: Neonatal intensive care unit (NICU), operating theatre or neonatal transport.
• Underlying respiratory conditions: respiratory distress syndrome, apnoea of prematurity, meconium aspiration syndrome, perinatal asphyxia, pneumonia.