Progesterone is produced by the ovaries and adrenal glands and plays an essential role in pregnancy. Progesterone prepares the uterus for implantation of the fertilized egg and then continues to secure the pregnancy.
Progesterone also works to balance the effects of estrogen. Think of estrogen as the gas pedal and progesterone as the brake. Progesterone reduces estrogen dominance and prevents breast cancer. There is a delicate balance between progesterone and estrogen; both have antagonistic and complementary effects to keep the body in homeostasis.
Below is a list of the functions and actions of progesterone
- Uterus – Prevents the development of endometrial cancer and helps prevent or decrease dysfunctional uterine bleeding. Progesterone may help decrease uterine contractions, cramping and pain.
- Vagina & Urinary Tract – Excess progesterone may counteract the beneficial effects of estrogen in maintaining urinary control and preventing vaginal dryness.
- Libido – Excess may diminish libido due to progesterone’s counteracting effects on estrogen and testosterone.
- Blood Sugar & Insulin – Can cause a decrease in insulin sensitivity having an effect on blood sugar (elevation) that is similar to glucocorticoids (steroids). This interference with the action of insulin can interfere with normal glucose uptake and cause insulin resistance.
- Brain, Mood & Memory – Progesterone and its metabolites result in increased relaxation and reduced anxiety in a way that is similar to the benzodiazepines (e.g. Valium or Xanax) by its direct effect on neurotransmitter receptors called Gamma-Amino Butyric Acid type A (GABAA) receptors. When progesterone levels drop, a woman can experience withdrawals similar to that seen with benzodiazepines, barbiturates and alcohol. This is the cause of post-partum depression. Progesterone also has a protective, stimulating effect on breathing patterns during sleep, resulting in decreased incidence of sleep apnea. It has also been associated with an increase in appetite and food intake.
- Breasts – Progesterone deficiency may play a role in the development of breast cancer; however, progesterone excess may also play a role in proliferation of some progesterone receptor forms of breast cancer.
- Skin – Progesterone promotes increased blood flow to the skin resulting in an improved ability to sweat and loose extra heat through the skin. Progesterone can also raise body temperature, enhancing the ability to tolerate cold.
- Bones – Progesterone has a stimulating effect on the bone building osteoblasts resulting in increased bone building activity. This is due to direct stimulation of the progesterone receptors in osteoblasts as well as increased secretion of growth factors by the bone cells exposed to progesterone. The most positive effect is seen when estrogen and progesterone are used in combination.
- Heart – May cause a significant lowering of blood pressure in postmenopausal women with mild to moderate high blood pressure, possibly due to the vasodilating effect of progesterone.
Common Symptoms of Progesterone Deficiency in Women
Most signs of progesterone deficiency are in fact signs of estrogen excess.
- Painful, swollen and/or cystic breasts
- Heavy menstrual cycles
- Increased pre-menstrual symptoms
- Endometrial hyperplasia and uterine fibroids
- Muscle and nerve tenseness
- Increased abdominal fat
- “Reddish” skin
- Increased irritability and anxiety
- Increased aggressiveness, especially during “PMS”
Requirements for Monitoring Therapy:
- Baseline and periodic blood tests including progesterone, estradiol, follicle stimulating hormone (FSH) and other hormone testing as appropriate.
- Baseline and periodic women’s exam including breast exam, mammography and PAP smear.
- Other tests that may be needed include: ultrasound imaging of the breast, ovaries and uterus and bone density scans.
Progesterone replacement is available in different formulations; the best route depends on the patient needs. Improvements may occur in the first week of treatment. However, full benefits of treatment may take up to three months. Natural forms of progesterone are preferred.
- Sublingual (under the tongue) tablets
- Trans-dermal (topical cream or patch)
- Oral capsules (acceptable but has marked increase in sedating metabolites)
- Pellet implants (not recommended)
Signs and Symptoms of Too Much Progesterone Replacement
- Sedation and excessive sleepiness
- Impaired memory and reasoning skills
- Decreased coordination
- Decreased libido
- Urinary Incontinence
- Excess vaginal dryness
When women are still having menstrual cycles, progesterone may be given for a few weeks in every monthly cycle. In a typical 28 day cycle it goes like this… Day 1-7 (menses) estrogen is naturally low so progesterone is not needed as much. About day 10 estrogen spikes and remains high until day 28 when it rapidly drops and the next cycle begins. About day 12 ovulation occurs and progesterone should quickly rise to balance the estrogen. If women are “estrogen dominant”, due to low progesterone, then they may take progesterone anywhere from day 7-28 in the cycle. Basically, start progesterone when menses ends and stop during menses.
Risks, Contraindications and Benefits of Treatment
- Nausea, bloating, breast tenderness, headache, change in vaginal discharge, mood swings, blurred vision, dizziness, unusual vaginal bleeding (e.g., spotting, breakthrough bleeding), mental/mood changes (e.g., depression, memory loss), swelling of the hands/feet, frequent/burning/painful urination, breast lumps, dark patches on the skin or face (melasma), yellowing eyes/skin, stomach/abdominal pain, persistent nausea/vomiting, dark urine, unusual tiredness.
- The Women’s Health Initiative used two synthetic hormone “look-alike” drugs called premarin (estrogens) and provera (progestin). Neither of these drugs are exactly the same (bioidentical) as human estrogen or progesterone. The results of this study showed the premarin only group had increased risk of stroke and blood clots. The premarin plus provera group had additional risks of heart attack and breast cancer.
- NOTE: Bioidentical HRT has been extensively studied and does not have the same risk profile as the drugs used in the Women’s Health Initiative.
- Active or untreated breast or uterine cancer is an absolute contraindication for all progesterone replacement.
- History of treated breast or uterine cancer is a relative contraindication and treatment should occur only with specific education as to the risk and benefits in this particular situation.
- Possible improvements in sleep, mood, energy, skin tone, sex drive
- Reduced risk of heart disease, osteoporosis, dementia, colon cancer, macular degeneration