Nighttime Vigilance Learning Shared by COMISA and Postpartum Insomnia — A Theoretical Reframing of Insomnia Persisting After the End of Infant Night Crying —

Insomnia in postpartum mothers is often attributed to external factors such as infant night crying and nocturnal feeding, and is therefore frequently regarded as a transient problem. However, accumulating evidence indicates that insomnia symptoms—including nocturnal awakenings and non-restorative sleep—may persist even after night crying has diminished or ceased. In this paper, we reframe this phenomenon not in terms of hormonal or psychological factors, but through the lens of insomnia theory, specifically the hyperarousal, conditioning, and learning model. Repeated responses to infant night crying require immediate and responsible nocturnal awakening, which facilitates the learning that nighttime is a period requiring vigilance. We propose that postpartum insomnia can be conceptualized as a state in which this nighttime vigilance learning fails to extinguish. Furthermore, we demonstrate the theoretical isomorphism between postpartum insomnia and COMISA (comorbid insomnia and obstructive sleep apnea), arguing that both conditions can be explained within a unified insomnia framework.