Progesterone's Impact on Egg Health and Fertility

Fertility rates, as well as U.S. birth rates, are at an all-time low.¹ While many women may feel a sense of hopelessness or urgency from such statistics, the truth is that pregnancy is individualistic.

What many data reports do not include is the reason for such a drop in fertility rates. When we take a look at how reproductive systems work with sex hormones, a clearer understanding of why and how fertility is affected begins to take form. As with many other health issues, improper functionality in the body arises from an imbalance at the molecular and cellular levels. When it comes to a woman’s egg health and fertility, the imbalance can be largely explained by the hormone progesterone.

What Is Progesterone?

Progesterone is a sex hormone that lies within a class of hormones we reference as steroid-based. Steroid-based hormones are made endogenously from cholesterol and include glucocorticoids, mineralocorticoids, androgens, oestrogens, and progestogens. 

Cholesterol can be broken down into two categories: high-density lipoproteins (HDL), or the good kind, and low-density lipoproteins (LDLs), the bad kind. In our society, dietary cholesterol has taken on a primarily “bad” label, though it is a necessary building block of hormones.

Progesterone Production and Function 

Progesterone is produced by the ovaries, adrenal glands, and placenta. In the female reproductive system, progesterone is often paired with estrogen. When progesterone levels drop, estrogen levels can spike and lead to estrogen dominance. In general, progesterone is involved with every stage of fertilization, from the menstrual cycle to proper fertilization and implantation of the egg to encouraging healthy development during pregnancy. 

During Menstruation

The female menstrual cycle happens every month and is the body’s way of preparing for potential conception. It occurs in two stages: the follicular stage and the luteal phase. It is during the two-week luteal phase that a temporary gland called copus lutem forms in the ovary. This gland produces larger amounts of progesterone, which helps thicken the endometrium lining of the uterus, prepping for proper implantation of a fertilized egg.² 

If you think of a classic 28-day reproductive cycle, progesterone has its day of activity around the midpoint of 14 days. It peaks around day 21, then tapers back down to baseline levels at day 28. So, when we talk specifically about reproductive function, progesterone is largely inactive until the second half of the reproductive cycle.

During Pregnancy

Once conception has occurred, the majority of the body’s progesterone production begins to switch over to the placenta. The placenta has three primary functions to support the healthy development of the fetus:

• Production of 4X the amount of progesterone
• Gas, nutrient, and waste exchange via vascularization
• Immunological barrier against toxins and microbial pathogens

Higher levels of progesterone help keep the uterine wall at optimal levels of vascularization, helping the body and the mother transfer her nutrients in an effective manner. Towards the end of a pregnancy, a drop in progesterone, as well as estrogen, helps enable lactation once the baby and placenta are delivered.³

Normal ranges of progesterone for adult women are listed below (ng/mL):⁴

• Pre-ovulation: Less than 0.89 
• Ovulation: ~12
• Post-ovulation: 1.8–24
• First trimester: 11–44
• Second trimester: 25–83
• Third trimester: 58–214

If progesterone is low, vascularization may be affected, and this can have damaging effects on the developing fetus. Low levels of progesterone can also result in pregnancy loss, as progesterone prevents the shedding of the uterine lining, as well as the muscular contractions typically seen during labor induction.⁵

How Stress and Progesterone Imbalance Affects Fertility

While progesterone plays several crucial roles related to egg health, fertility, and pregnancy, it doesn’t impact the fetus directly, but a mother’s state of stress, quality of nutrition, amount of sleep, and hydration can. This means there is a chance that a woman with an exceptionally unhealthy diet can still conceive a healthy child with sufficient levels of progesterone.

However, as mentioned previously, dangerously low progesterone levels early on can result in a failure to implant and have a successful pregnancy. It can even result in unsuccessful fertilization. During pregnancy, this can mean a miscarriage. So, what can cause such consistently low levels of progesterone production?

As a clinician, I start by asking about irregular menstrual cycles. This includes questions regarding the timing, duration, intervals, and quality of flow, as well as associated symptoms such as cramps, migraines, or mood swings. Typically, menstrual irregularities are accompanied by low levels of progesterone levels and are early indicators of potential fertility issues.

Another commonly seen indicator of low progesterone among women is the formation of occasional ovarian cysts. As progesterone levels drop, an excess amount of estrogen becomes present. With estrogen dominance, there is an increased risk for tumor growth via excessive multiplication of cells, hence the formation of cysts. Indicators of estrogen dominance include changes in immune function, changes in dietary cravings, a decrease in metabolism, and changes in weight gain, sleep quality, and sex drive.  

However, a large portion of women have lower than normal levels of progesterone, primarily due to stress. Your adrenals produce cortisol, which is a stress hormone, also synthesized from cholesterol. What we know about the functional connection between progesterone and cortisol is that when cortisol drops as a result of stress, especially in women, the body has to make up for that loss. In this scenario, the body will steal progesterone and convert it quickly and efficiently to cortisol. With chronic stress being rampant in today’s society, the link between depleted cortisol levels and, subsequently, lower progesterone levels must be addressed.

Related Content: Does CoQ10 Affect Egg Quality and Fertility?

Tips for Balancing Out Progesterone Levels

Luckily, several natural solutions can be implemented in a woman’s diet and lifestyle to ensure a more promising fertility outcome. The first solution to ensuring the proper production of endogenous progesterone is to maintain a healthy balance of both LDL and HDL cholesterol in the diet. This can include substituting fast food or highly processed snacks for options like avocados, nuts, and seeds. 

The second recommendation is to consider adding supplements to the diet. Methylated B vitamins function as a cofactor in hormone synthesis. Wild yam extract is utilized as a bio-identical precursor to progesterone in both transdermal creams and supplements. However, research has shown that the precursor, diosgenin, isn’t easily converted into progesterone and doesn’t provide an adequate amount of absorbed progesterone.⁶ Thus, women interested in a progesterone transdermal cream should talk to their physician before trying such hormonal therapy.

Chaste berry supplements can help increase sensitivity to existing progesterone, while indole-3-carbinol (I3C) and diindolylmethane (DIM) help clean up any dysfunctional estrogen production or estrogen dominance. So, in combination, these supplements work on both ends by targeting the chemical imbalances of progesterone and estrogen at the same time.  

Reduce Stress to Support Progesterone Levels 

Stress can profoundly impact progesterone production, especially if the body begins to supplement depleted levels of cortisol with progesterone conversion. When this happens, many women are left with low levels of progesterone. Estrogen dominance and the negative symptoms associated with this condition can affect women who deal with reproductive issues as a result of low progesterone. Approaches to solving these issues and obtaining a balanced reproductive system include incorporating a proper diet, stress reduction to alleviate the stealing effect of progesterone, and supporting the actual progesterone level itself through various supplemental and transdermal applications. These paths can lead to a healthier, happier pregnancy, even after your child is born.

By Ramneek S. Bhogal, DC, DABCI

^SOURCES:

^{1 “Birth in The United States, 2018 - NCHS.” 2019. https://www.cdc.gov/nchs/products/databriefs/db346.htm. Accessed August 26, 2019.}

^{2 “How Does The Corpus Luteum Affect Fertility? - Healthline.” 2019. https://www.healthline.com/health/womens-health/corpus-luteum. Accessed August 26, 2019.}

^{3“Control of Hormone Release During Lactation - NCBI.” 1978. https://www.ncbi.nlm.nih.gov/pubmed/361330. Accessed August 26, 2019.}

^{4“Everything You Need To Know About Progesterone - Healthline.” 2019. https://www.healthline.com/health/womens-health/corpus-luteum. Accessed August 26, 2019.}

⁵ “Placenta - Society of Endocrinology.” https://www.yourhormones.info/glands/placenta/. Accessed August 26, 2019

^{6“Bioidentical Hormone Therapy: Clarifying the Misconceptions - Cleveland Clinic Journal of Medicine.” 2011. https://www.mdedge.com/ccjm/article/95466/womens-health/bioidentical-hormone-therapy-clarifying-misconceptions/page/0/2. Accessed August 26, 2019.}