Progesterone and menstrual period
Function, Deficiency, and Hormone Support
Progesterone is a critical hormone produced primarily by the ovaries after ovulation (corpus luteum), and in smaller amounts by the adrenal glands and during pregnancy by the placenta. It plays a key role in regulating the menstrual cycle, supporting pregnancy, and balancing the effects of estrogen.
How Progesterone Is Made in the Female Body
- Produced from cholesterol, through conversion to pregnenolone, then progesterone
- Synthesized in the corpus luteum after ovulation in the second half of the menstrual cycle
- Also secreted by the adrenal glands during stress and by the placenta during pregnancy
Progesterone in Perimenopause & Menopause
- Ovulation becomes irregular, leading to insufficient progesterone production
- Estrogen may remain high or fluctuate, creating "estrogen dominance" relative to low progesterone
- In menopause, progesterone production drops to near zero unless supplemented
Effects of Low Progesterone-System Effect of Deficiency
Brain & Sleep - poor sleep quality, insomnia, increased anxiety or worry
Mood & Anxiety - Increased risk of depression, irritability, mood swings
Reproductive System - Irregular periods, heavy bleeding, PMS, infertility
Uterus - Higher risk of endometrial hyperplasia (if unopposed estrogen)
Post-hysterectomy - Still beneficial for sleep, mood, and breast protection
Progesterone Metabolism: Key Pathways
- Pregnenolone → Progesterone →Allopregnanolone:
Neuroactive metabolite that enhances GABA, promoting calm, sleep, and reduced anxiety
- Other pathways include cortisol and aldosterone synthesis
Optimal Dosing & Forms of Progesterone
Oral micronized (bioidentical) - Best for sleep, converts to allopregnanolone in liver
Topical cream - Useful for mood/PMS, bypasses liver metabolism
Vaginal (capsules/gel) - Local uterine effect, fertility support
Typical Dose for Menopausal Support:
- Oral: 100–200 mg at bedtime (micronized, bioidentical)
- Topical: 20–40 mg/day (adjust based on labs and symptoms)
Risks of High Progesterone (Uncommon but Possible)
- Sedation, fatigue
- Dizziness or brain fog
- Breast tenderness
- Bloating
- Depressed mood (rare)
These are usually dose-related or due to metabolic sensitivity and resolve with dosage adjustment.
๏ปฟ
Summary
Progesterone is a cornerstone hormone in women's health, supporting mood, sleep, cognition, menstrual regulation, and cancer protection. Its decline in perimenopause and menopause can trigger a cascade of symptoms—but when restored safely through bioidentical hormone replacement, it can dramatically improve quality of life.
Even post-hysterectomy, progesterone offers neurological, psychological, and metabolic benefits, making it a key component of balanced hormone therapy when used thoughtfully and monitored with labs.
let’s take a closer look at how low progesterone contributes to irregular or heavy periods and breast tenderness particularly in menstruating women or those with estrogen dominance.
Irregular or Heavy Periods: How Low Progesterone Causes It
- After ovulation, the corpus luteum produces progesterone to stabilize the endometrial lining.
- If no ovulation occurs (anovulatory cycle), there’s no progesterone.
- Estrogen continues to build the uterine lining, but with no progesterone to balance or shed it properly, the result is: Heavy bleeding (menorrhagia), Excessively thickened endometrium is shed irregularly and unpredictably, Clotting and prolonged periods are commo ,Irregular cycles, Cycles may be longer, shorter, or skipped altogether, Often seen in perimenopause, PCOS, or chronic stress/anovulation
Think of progesterone as the “off switch” for estrogen’s growth-stimulating effects on the uterine lining.
Breast Tenderness: The Role of Progesterone Imbalance
- Estrogen stimulates breast tissue proliferation and fluid retention
- Progesterone normally balances this effect, reducing stimulation and inflammation
If progesterone is low:
- Estrogen acts unopposed, leading to:
- Swollen, dense, painful breasts
- Commonly felt in the luteal phase (days 21–28) of the cycle
- More pronounced if there’s estrogen dominance or xenoestrogen exposure (plastics, chemicals)
How Progesterone Replacement Helps
For heavy periods Progesterone Stabilizes endometrium, reduces bleeding
for Irregular periods Progesterone Re-establishes rhythm via withdrawal bleed
for Breast tenderness Progesterone Opposes estrogen, reduces tissue sensitivity
Forms like oral micronized progesterone are often used cyclically to restore balance, especially in women with:
PCOS, Perimenopause, Anovulatory cycles
Here’s a detailed breakdown of the menstrual cycle hormonal physiology, including day-by-day hormone shifts
Overview of the Menstrual Cycle
- Average length: 28 days (can range from 24–35 days)
- Divided into 2 main phases:
- Follicular Phase (Day 1–14)
- Luteal Phase (Day 15–28)
- Ovulation typically occurs around Day 14
Day-by-Day Hormonal Timeline
Day 1–5↓ Estrogen & progesterone - Menstrual bleeding begins as hormone levels drop; the endometrial lining is shed
Day 6–12↑ FSH → ↑ EstrogenFSH (from pituitary) stimulates follicle growth; estrogen thickens the uterine liningDay 13–14LH surge, peak estrogenHigh estrogen triggers LH surge → ovulation (release of the egg)Day 15–21↑ Progesterone (from corpus luteum)Corpus luteum forms and secretes progesterone → stabilizes and matures the endometriumDay 22–28↓ Progesterone & estrogen (if no pregnancy)Corpus luteum regresses → hormone levels fall → endometrial shedding begins again (Day 1)
๐งฌ Why We Bleed Each Month (Normal Physiology)
- In the second half of the cycle (luteal phase), progesterone prepares the endometrial lining for implantation.
- If no pregnancy occurs, the corpus luteum breaks down → sudden drop in progesterone and estrogen.
- This hormone withdrawal triggers:
- Vasoconstriction of spiral arteries
- Tissue breakdown and inflammatory mediators (prostaglandins)
- Endometrial shedding = menstruation
๐จ Why Some People Have Heavy Bleeding
๐น Hormonal Causes:
- Low progesterone or no ovulation (anovulation) → unopposed estrogen keeps building up the uterine lining
- When it sheds, it's thicker = heavier bleeding
- PCOS, perimenopause, and thyroid disorders are common culprits
๐น Other contributors:
- Low thyroid function (hypothyroidism): Impaired metabolism of estrogen → heavier bleeding
- High estrogen states (obesity, xenoestrogens, fibroids, endometrial hyperplasia)
- Coagulopathies or inflammation (excess prostaglandins)
๐ง Systemic Hormonal Control of the Menstrual Cycle
๐งฌ 1. Hypothalamus → GnRH
- Pulsatile GnRH controls the cycle start
- Signals pituitary to release FSH and LH
๐ง 2. Pituitary → FSH & LH
- FSH = follicle growth
- LH surge = triggers ovulation
๐งต 3. Ovaries → Estrogen & Progesterone
- Estrogen = grows lining, matures follicle
- Progesterone = stabilizes lining after ovulation
๐ง How Other Hormones Participate
๐ฃ Thyroid Hormones (T3, T4)
- Regulate metabolism of estrogen and progesterone
- Hypothyroidism → ↓ SHBG → ↑ free estrogen → estrogen dominance symptoms
- Can impair ovulation → low progesterone → heavy or irregular bleeding
๐ Cortisol (Adrenal)
- Chronic stress → ↑ cortisol → suppresses GnRH → anovulation
- Leads to progesterone deficiency and menstrual irregularities
๐ก Insulin
- High insulin (from IR/PCOS) → stimulates ovarian theca cells → ↑ androgens → disrupted ovulation
๐ง Neuroendocrine Feedback Loops Summary
Gland/OrganHormoneActionHypothalamusGnRHStarts the cycle, pulses regulate FSH/LHPituitaryFSH, LHFSH grows follicles; LH triggers ovulationOvariesEstrogen, ProgesteroneBuild & stabilize uterine liningAdrenalsCortisolChronic excess suppresses ovulationThyroidT3, T4Required for ovulation and hormone metabolismPancreasInsulinExcess disrupts ovaries and estrogen metabolism
๐ง Summary
- Menstruation is triggered by a drop in progesterone and estrogen after an unsuccessful luteal phase
- Heavy or irregular periods are most often due to low or missing progesterone, usually from anovulation
- Other hormones (thyroid, cortisol, insulin) deeply affect the cycle by influencing ovulation, estrogen metabolism, and endometrial stability
Menstrual Cycle Hormone Physiology & Imbalance Overview
๐ฉธ Menstrual Cycle Phases (28-Day Model)
Day 1–5: Hormones drop (estrogen & progesterone) → Menstrual bleeding begins.
Day 6–12: FSH rises → Follicle matures → Estrogen increases → Endometrial growth.
Day 13–14: Estrogen peaks → LH surge triggers ovulation.
Day 15–21: Progesterone rises → Endometrium stabilizes for implantation.
Day 22–28: If no pregnancy → Estrogen & progesterone drop → Lining breaks down → Bleeding begins again.
๐งฌ Why We Bleed
Bleeding occurs due to a sharp drop in progesterone and estrogen when implantation doesn’t occur. This withdrawal triggers vasoconstriction in uterine arteries, tissue breakdown, and the shedding of the endometrial lining.
๐จ Causes of Heavy or Irregular Bleeding
- Low or absent progesterone (often due to anovulation)
- Unopposed estrogen → overgrown endometrium
- Hypothyroidism → decreased hormone clearance, increased estrogen
- Chronic stress → cortisol suppresses ovulation
- PCOS → irregular cycles, elevated androgens, impaired ovulation
๐ง Hormonal Control Summary
- Hypothalamus → GnRH → Pituitary → FSH & LH
- FSH → follicle development
- LH surge → ovulation
- Ovaries → estrogen (follicular), progesterone (luteal)
๐ Key Hormones and Their Roles
- Estrogen: Grows uterine lining, supports follicle maturation
- Progesterone: Stabilizes and matures endometrium post-ovulation
- Cortisol: Chronic elevation suppresses GnRH → disrupts ovulation
- Thyroid Hormones (T3, T4): Support ovulation, SHBG, metabolism of sex hormones
- Insulin: Excess promotes androgen excess → disrupts cycle (PCOS)
๐งช Suggested Hormone Testing Timeline
Day 2–5: FSH, LH, Estradiol, AMH (baseline fertility panel)
Day 19–21: Progesterone (to confirm ovulation)
Anytime: TSH, free T3/T4, insulin, cortisol (morning), DHEA-S, prolactin
๐ฉบ Supporting Hormonal Balance by Phase
Follicular (Day 1–14):
- Support estrogen clearance: cruciferous veggies, DIM, liver support
- Gentle detox & anti-inflammatory lifestyle
Luteal (Day 15–28):
- Support progesterone production: vitamin B6, magnesium, zinc
- Reduce stress & support adrenal health (adaptogens, sleep hygiene)
