The endocrinology of the menstrual cycle.
Level 5 - mechanism / opinion, no new human data
Narrative review of established physiological mechanisms with no original empirical data.
PubMed 24782009 · doi:10.1007/978-1-4939-0659-8_7
What was done
This is a narrative review describing the endocrine feedback loops coordinating the hypothalamus, pituitary gland, ovaries, and endometrium throughout the normal menstrual cycle. The abstract reports no empirical clinical trial, experimental study design, or systematic search methodology.
What was found
The abstract details established regulatory intervals: hypothalamic GnRH is secreted in pulses every 1–1.5 hours in the follicular phase and every 2–4 hours in the luteal phase. These pulses drive pituitary LH and FSH release. LH stimulates thecal androstenedione production, which granulosa-cell aromatase (Cyp19, stimulated by FSH) converts to estradiol. Rising estradiol from the dominant follicle triggers positive feedback via the kisspeptin system to induce the mid-cycle LH surge and subsequent ovulation. Post-ovulation, the corpus luteum secretes progesterone to transform the proliferating endometrium into a secretory epithelium optimized for embryo implantation. No quantitative clinical trial data or statistical metrics were reported.
Why it matters
It synthesizes the core neuroendocrine and steroidogenic pathways that govern human follicular development, ovulation, and endometrial receptivity.
Limits
The record is purely descriptive mechanism-based scholarship with no original participant data, control groups, or clinical outcome measurements. It does not address inter-individual endocrine variation, anovulatory disorders, or pathological states.
Cited by
- supports The corpus luteum has a lifespan of approximately two weeks unless rescued by human chorionic gonadotropin (hCG) from an implanting embryo.