Circadian Timing of the Female Reproductive System

Abstract

Precise chronological transition is critical for a normal female reproductive system. Many epidemiologic studies have demonstrated rhythmicity in parturition during the resting phase, and even seasonal breeding. Circadian rhythms are controlled by a multi-oscillatory circadian system. These rhythms are determined by both genetic and environmental factors. The female reproductive axis is also highly rhythmic, and the hypothalamic-pituitary-gonadal axis and the hypothalamic-pituitary-adrenal axis are also functional multi-oscillatory circadian systems. Bidirectional communication between the central and peripheral tissue clocks is essential for maintaining the rhythm from ovulation to parturition. This review discusses the circadian timing of the female reproductive system, specifically its underlying metabolic and molecular clock functions. This review particularly focused on the following areas: multi-oscillatory system in the female reproductive system; the ovarian cycle and the timing of ovulation; timing of mating and seasonal reproduction; circadian rhythms in pregnancy; circadian timing of labor onset and parturition.