Four hormones layered on one timeline
A full overlay shows how four hormones interlock across roughly 28 days. Follicle-stimulating hormone (FSH) rises early to recruit ovarian follicles. Estradiol climbs through the follicular phase as those follicles grow. When estradiol reaches a high enough sustained level, it flips from inhibiting to stimulating the pituitary, triggering a sharp luteinizing hormone (LH) surge.
That LH surge is the immediate trigger for ovulation, usually within about a day. Reading the curves together shows the LH spike sitting at the estradiol peak, not arriving independently.
What the luteal phase adds
After ovulation, the corpus luteum secretes progesterone, which rises through the luteal phase and dominates the second half of the overlay. Progesterone and residual estradiol suppress FSH and LH through negative feedback, preventing a second ovulation. If no pregnancy occurs, these hormones fall and the cycle restarts.
The relative heights and exact timing differ between individuals and cycles. This is general educational information, not medical advice; cycle interpretation for health or fertility decisions belongs with a qualified professional.