Nocturnal Synchronization and Synergy of Interactive Inhibitory and
Stimulatory Systems Secondary to Light Dark Cycle Modulation Dictates
Timing of Birth and Pregnancy Duration: A Hypothesis III
Abstract
Objective: The clock that measures the duration of pregnancy consists of
two interacting timers: an interval timer measuring the overall length
of gestation, and a circadian timer defining when within a 24-hour cycle
birth occurs, and they have not been definitively established or
systematically studied and our objectives to study pregnancy interval
and circadian timers. Design: Research Study Setting: Portiuncula
University Hospital, Ireland Population: N/A Methods: This study
investigated the current evidence-based literature and research that may
support our proposed hypothesis, accompanied by a 40-second 3D
animation. Main Outcome Measures: N/A Results: Gestation is divided into
five clinical phases, growth, maturation, transition, parturition, and
involution secondary to light-dark cycle modulation of the interactive
inhibitory and stimulatory systems. During the maturation phase (30-37
weeks), the inhibitory system transiently wears off due to cortisol
modulation. This occurs alongside the modulation of melatonin and
oxytocin, and the latter induces contractions of the stimulatory system,
resulting in nocturnal synchronization and synergy of the two systems
and causing the cervix to lose its strength by transforming it into the
lower uterine segment. Pregnancy interval and circadian timers are
achieved by a single mechanism, that is, exponential uterine wall
tension (EUWT) failure, secondary to the complete loss of cervical
resistance nocturnally. Conclusion: The creation, autonomic maintenance,
and eventually autonomic termination of the EUWT make gestation an
autonomic cycle with constant intervals and circadian timers. There is
evidence-based support for the hypothesis which will have an impact on
obstetric practice and maternal and family welfare.