All About Your Fertility Hormones: FSH, E1G, LH, PdG, and HCG

Ellie Diamond
Ellie Diamond
February 24, 2024
min read
Medically reviewed by:
Trager Hintze, PharmD
All About Your Fertility Hormones: FSH, E1G, LH, PdG, and HCG

The information age has given women more control over their fertility, and learning about hormones is one of the most important steps you can take. Learn the facts about your fertility hormones and how to monitor them.

Your Fertility Hormones and What They Do

Fertility is a hormone-driven process. Each hormone drives a unique set of changes that move your cycle along, from egg maturation to pregnancy or menstruation.

Estrone Glucuronide (E1G)

Estrone glucuronide (E1G) is a biological marker of estrogen levels in the body. When increasing levels of E1G are present in the urine, it signifies ovarian follicle growth and an impending fertile period.

E1G release levels usually increase by 30% to 40% during the fertility cycle before decreasing sharply mid-cycle [1]. Ovulation begins when E1G peaks, marking the beginning of the fertile window.

Follicle-Stimulating Hormone

Follicle-stimulating hormone (FSH) stimulates the body to produce estrogen, which encourages the growth of structures called ovarian follicles [2]. Each ovarian follicle is a collection of fluid containing a single egg.

The body releases FSH at the beginning of your cycle, prompting the growth of several follicles. The follicle that grows the largest will release that cycle's egg [3].

Luteinizing Hormone

Luteinizing hormone (LH) works alongside FSH to trigger follicle growth and the release of an egg. FSH and LH both act on the follicular cells, leading to a shut-off of the processes that usually limit LH production. Levels of LH increase sharply, encouraging the follicle to release the egg [4].


Progesterone is a steroidal hormone that supports embryo implantation and ongoing pregnancy. The release of progesterone causes structural changes in the uterine lining, developing additional small blood vessels. This microvascular development allows the embryo to implant and remain implanted in the endometrium.

Without sufficient levels of progesterone, a woman is at a significantly higher risk of infertility or pregnancy loss [5].

Pregnanediol Glucuronide

Pregnanediol glucuronide (PdG) is a marker of progesterone levels. Ovulation occurs between the E1G peak and increased PdG levels in the urine. Measuring PdG levels can confirm ovulation and estimate whether a woman has sufficient progesterone levels to maintain pregnancy [6].

Human Chorionic Gonadotropin (HCG)

Human chorionic gonadotropin (HCG) is a crucial driver of progesterone production during pregnancy. HCG develops in a specific tissue type found in young embryos and placental cells [7].

In healthy pregnancies, HCG levels increase in the first 10 weeks of gestation and gradually decrease until the 16th week. From 16 weeks to term, levels stay relatively stable. An early decrease in HCG levels may signal impending pregnancy loss [7].

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The Role of Hormones in the Fertility Cycle

A woman's fertility cycle, also known as the menstrual cycle, typically ranges from 24 to 38 days [8].

The rise and fall of hormone levels drive the development of the menstrual cycle. Understanding the process can help you understand your fertility and what tests or treatments may help.


The fertility cycle begins with the menstrual bleeding phase, clinically known as the follicular phase. Two key processes occur during this phase.

One is the shedding of the endometrium, the thickened uterine lining that develops to prepare for embryo implantation. Low levels of estrogen and progesterone drive this process.

At approximately the same time, FSH levels increase, prompting the growth of a cohort of ovarian follicles. One of those follicles becomes dominant and secretes high estrogen levels to prepare for ovulation [9].


Rising estrogen levels cause a surge in FSH and LH. The LH surge stimulates egg release from the dominant follicle, usually 16 to 32 hours after the initial hormonal surge [8].

At the same time, estrogen levels decrease, and progesterone increases. LH levels fall significantly after ovulation is complete [9].

Luteal Phase

The luteal phase begins at ovulation and lasts approximately 14 days [9]. During this time, non-released follicular cells combine with other cells in the ovaries to become a hormone-releasing organ called the corpus luteum, which releases progesterone to prepare for and maintain pregnancy.

Progesterone is the hormone that prepares the uterine lining for pregnancy by creating new capillaries. Peak blood flow happens around nine days after ovulation when progesterone and estrogen are also at peak levels. At that time, the uterus is preparing for potential fertilization [10].

If pregnancy occurs, the body will release HCG to keep the corpus luteum active. If not, the structure dissolves, and estrogen and progesterone decrease. This begins menstruation and the cycle restarts.


In the absence of a medical disorder or surgical interruption, a woman's fertility cycle continues until menopause. Menopause is not a moment in time but a multi-year transition during which reproductive hormones fluctuate dramatically.

These hormonal fluctuations lead to changes in the timing of a woman's fertility cycle. Those changes typically begin four to eight years before a woman's last period [11].

Most women experience menopause between 46 and 55 years of age. Menopause is premature before age 40 and early but normal between 41 and 45.

How Hormonal Imbalances Impact Fertility

Hormones prompt the chemical reactions that drive the fertility cycle. If hormone levels are abnormal, it can affect a woman's ability to conceive. For example:

  • Low FSH levels may indicate a failure of the ovaries to produce and release eggs [12]
  • Low LH at ovulation may reduce the chances of conception [13]
  • Low progesterone or impaired progesterone reactions may prevent a successful pregnancy [14]

If you have concerns about your fertility or have had trouble getting pregnant, an evaluation of your fertility hormones could offer answers.

Testing and Monitoring Fertility Hormones

Hormone testing is a common way of monitoring and assessing fertility. Many women test at home using over-the-counter products.

One famous example is the urine test for ovulation production, which measures LH levels. These measure the LH surge that precedes ovulation [15]. Another option is the PdG test.

But what is a PdG test? This option is newer, and many women are still unfamiliar with it.

The PdG test evaluates progesterone levels to confirm ovulation. Because PdG levels change after the LH surge, a PdG test can offer results during the fertility window [16].

Clinics and physicians' offices may also do urine or blood testing to evaluate fertility hormones [17]. A healthcare provider will choose the most appropriate tests based on an interview and physical exam.

Follow the Diagnox blog to learn more about at-home medical testing and how it can help you take control of your health.


[1] L. Blackwell, D. Cooke, and S. Brown, "Self-Monitoring of Fertility Hormones," The Linacre Quarterly, vol. 85, no. 1, pp. 26—34, 2018. [Accessed Jan. 5, 2024].

[2] SR. Park, SR. Kim, SK. et al., "A novel role of follicle-stimulating hormone (FSH) in various regeneration-related functions of endometrial stem cells." Exp Mol Med 54, 1524–1535 (2022).

[3] University of California, San Francisco Health: "The Menstrual Cycle."

[4] D. Nedresky and G. Singh, "Physiology, Luteinizing Hormone," StatPearls, [Accessed Jan. 5, 2024].

[5] C. Bulletti, F.M. Bulletti, R. Sciorio, and M. Guido, "Progesterone: The Key Factor of the Beginning of Life," The International Journal of Molecular Sciences, 23(22): 14138. [Accessed Jan. 5, 2024].

[6] A. Beckley, J. Klein, J. Park, et al., "The predictive value of urinary progesterone metabolite PdG testing in pregnancy outcomes." Obstetrics and Gynecology Research 5 (2022): 194-198.

[7] D. Betz and K. Fane, "Human Chorionic Gonadotropin," StatPearls, [Accessed Jan. 5, 2024].

[8] Merck Manual: "Menstrual Cycle."

[9] B. Reed and B. Carr, "The Normal Menstrual Cycle and the Control of Ovulation," Endotext, [Accessed Jan. 5, 2024].

[10] Merck Manual: "Healthy Living: Menstrual Cycle."

[11] Merck Manual: "Menopause."

[12] University of Rochester Medical Center: "Follicle-Stimulating Hormone."

[13] D.D. Baird, C. Weinberg, H. Zhou, et al., "Preimplantation urinary hormone profiles and the probability of conception in healthy women," Fertility and Sterility, vol. 71, Issue 1, January 1999, Pages 40-49.

[14] S. Vannuccini, V. Clifton, I. Fraser, et al., "Infertility and reproductive disorders: impact of hormonal and inflammatory mechanisms on pregnancy outcome," Human Reproduction Update, vol. 22, Issue 1, January/February 2016, Pages 104–115.

[15] MedlinePlus: "Ovulation home test."

[16] T. Bouchard, R. Fehring, and M. Schneider, "Pilot Evaluation of a New Urine Progesterone Test to Confirm Ovulation in Women Using a Fertility Monitor," Frontiers in Public Health, vol. 7, 2019.

[17] American Pregnancy Association: "Understand Your Fertility Tests."

About the Author
Ellie Diamond

Ellie Diamond is a freelance writer with a background in the arts and mental health. She received a BA from Emerson College and an MA in creative arts therapies from Lesley University. Using her work experience as a teacher and tutor, she has focused her writing on explaining complex topics to a lay audience. Those topics include personal health management and wellness.

About the Reviewer
This blog was
Medically reviewed by:
Trager Hintze, PharmD

Trager Hintze is a clinical assistant professor and emergency medicine clinical pharmacist located in College Station, Texas. He has a bachelor's degree in biology as well as a Doctor of Pharmacy degree. He balances teaching at Texas A&M University College of Pharmacy and practicing emergency medicine at St. Joseph Regional Health Hospital.

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