Health & Longevity Series · Medical education

The hormones of fertility

How the reproductive hormones work together

3 min read

01Overview

The hormones that govern fertility

Key takeaway for patientsFertility hormones work as a set and change through the cycle. A single number means little; a physician reads them together and at the right time.

Fertility is coordinated by a small set of hormones. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH), from the pituitary, act on the ovaries and testes. In women they drive the growth of a follicle, ovulation and the production of estradiol and progesterone; in men, sperm production and testosterone.

Other markers add detail: anti-Müllerian hormone (AMH) reflects ovarian reserve, and prolactin and thyroid hormones can disturb the cycle when they are out of range. Levels shift through the menstrual cycle, so timing matters when they are measured.

02Key steps

Key steps in the menstrual cycle

FSH: Stimulates the growth of a follicle in the ovary; in men, sperm production.
Estradiol: Rises as the follicle grows and builds the lining of the uterus.
The LH surge: Triggers ovulation.
Progesterone: Made by the corpus luteum after ovulation; prepares the lining for implantation.

03Factors in decline

Factors that disturb fertility hormones

Several factors alter these hormones or the response to them:

Age: Ovarian reserve declines; in men the changes are more gradual.
Body weight and energy balance: Both low and high body fat disturb ovulation.
Thyroid and prolactin disorders: Interfere with the signals from the pituitary.
Chronic stress, smoking and alcohol: Affect hormone levels and the quality of eggs and sperm.

04Clinical management

Clinical management and physician guidance

Both partners are assessed, and tests are timed to the cycle.

Hormone and reproductive assessment: Cycle-timed blood tests, semen analysis and ultrasound where indicated.
Physician-guided care: Lifestyle measures and care as your physician decides, with referral to a fertility specialist where needed.
Monitoring and follow-up: Symptoms and markers are reviewed over time, and the plan is adjusted to them.

05Research focus

Research focus in reproductive endocrinology

Core focus area	Biological target	Clinical relevance
Gonadotropins	FSH and LH receptors	Follicle growth and ovulation
Ovarian reserve	Anti-Müllerian hormone	The number of remaining follicles
Luteal function	Progesterone from the corpus luteum	Preparation of the uterine lining
Male factors	Testosterone and Sertoli cell function	Sperm production

06Questions

Frequently asked questions

Why are fertility hormones tested on particular days?: Levels change through the cycle, so the day of testing determines what a result means.
What does AMH tell me?: It reflects the number of remaining follicles. It does not by itself say whether you can conceive.
When should a couple seek advice?: If pregnancy has not happened after a year of trying, or sooner where the woman is over 35 or there is a known condition.

07References

Academic references and literature

Broekmans FJ, Soules MR, Fauser BC (2009). Ovarian aging: mechanisms and clinical consequences. Endocr Rev, 30(5), 465-93. PMID 19589949.
Dewailly D et al. (2014). The physiology and clinical utility of anti-Mullerian hormone in women. Hum Reprod Update, 20(3), 370-85. PMID 24430863.
Messinis IE, Messini CI, Dafopoulos K (2014). Novel aspects of the endocrinology of the menstrual cycle. Reprod Biomed Online, 28(6), 714-22. PMID 24745832.

This guide belongs to the Hormone Therapy program