Pregnancy is a State of Balance Between Opposing and Interactive
Inhibitory and Stimulatory Systems Secondary to Exponential Uterine Wall
Tension and Laplace’s Law: A Hypothesis II
Abstract
Objective: Labor is viewed as the result of a physiologic release from
an inhibitory effect of pregnancy on the myometrium, rather than an
active process mediated by contractile agonists. The contractile
stimulators and relaxation mechanisms have not yet been well defined.
The objective of the study is to identify the systems that control
uterine function during pregnancy. Design: Research Study Setting:
Portiuncula University Hospital, Ireland Population: N/A Methods: This
study investigated the current evidence-based literature that may
support the hypothesis, accompanied by a 40-second 3D animation. Main
Outcome Measures: N/A Results: Uterine mechanotransduction has
functional and molecular components, wherein the exponential uterine
wall tension (EUWT) is the functional component, and the intrinsic
myometrial cell character (IMCC) is the molecular component. IMCC
enables the uterus to control its functions both autonomically and
intrinsically, secondary to changes in tension. EUWT is measured by
Laplace’s Law and is created and maintained by interaction among the
gestational sac, uterus, and cervix, for which the primary function is
to maintain the EUWT. Directly, EUWT mechanotransduction and
progesterone/estrogen stimulation induce the inhibitory system and
indirectly, they induce the stimulatory system by inducing myometrial
hyperplasia and hypertrophy. The inhibitory system is the main system
that maintains pregnancy through a stretch-dependent mechanism. The
stimulatory system makes the cervix lose its strength through the YVU
pattern formation by transforming it into the lower uterine segment,
thus terminating the pregnancy. Conclusion: There is evidence-based
support for the hypothesis which might be the first step in uncovering
the human parturition’s mystery.