The Hormonal Loop and Ovulation
How follicle-stimulating hormone and luteinizing hormone coordinate the menstrual cycle and fertility windows.
9 min read · Reference: Endocrine Society patient resources
The menstrual cycle begins with the brain signaling the ovaries via follicle-stimulating hormone (FSH). Ovarian follicles mature and produce estrogen, which thickens the uterine lining and triggers the mid-cycle luteinizing hormone (LH) surge.
Ovulation typically occurs about 24–36 hours after the LH surge. The released egg remains fertilizable for roughly 12–24 hours, while sperm may survive several days in reproductive tract fluid—creating a wider fertile window than ovulation day alone.
After ovulation, the corpus luteum produces progesterone to support the lining. If pregnancy does not occur, hormone levels fall and menstruation begins. Cycle length variability is common, especially in teens and perimenopause.
Tracking cervical mucus, basal body temperature, or urinary LH kits can improve body literacy. These methods are educational and may support fertility awareness goals but require training for contraceptive use.
Medical disclaimer
This article is original educational content from Aegis Education. It is not medical advice, diagnosis, or treatment. For personal health concerns, contact a licensed healthcare professional or local emergency services when urgent care is needed.