Despite an impressive amount of effort and extensive research, our knowledge of parturition remains scant. Although numerous scientists have investigated “the timing of birth”, we still have a limited understanding of the biological mechanisms that control events initiating delivery, or the availability of methods supposed to prevent these mechanisms from acting inappropriately. A multitude of factors and structures are involved; the myometrium, cervix, placenta and the fetus must act in concert to assure successful delivery. We do know that achievement of a “perfect” contractile force is not the sole factor. Successful delivery is also impacted by subtle differences in pelvic shape or size.