Progesterone is a vital hormone that plays a key role in many aspects of women's health. Whether naturally occurring in the body or prescribed as part of hormone replacement therapy (HRT), progesterone influences everything from the menstrual cycle to maintaining pregnancy. This article explores the importance of progesterone, its uses in HRT, the types of progesterone available, issues related to progesterone intolerance, its role in reducing histamine response, and its overall benefits.
What Is Progesterone?
Progesterone is a hormone produced primarily by the ovaries after ovulation during the second half of the menstrual cycle. It is crucial for regulating the cycle and preparing the body for pregnancy. If conception occurs, progesterone helps maintain the early stages of pregnancy by thickening the uterine lining. If pregnancy does not occur, progesterone levels drop, triggering menstruation.
Besides its role in reproduction, progesterone affects various body systems, including the brain, bones, skin, and immune response. It helps balance the effects of oestrogen, another important hormone, and contributes to overall hormonal health.
Progesterone and HRT
Hormone replacement therapy (HRT) is commonly used to manage symptoms associated with menopause, such as hot flushes, mood swings, and vaginal dryness. During menopause, the ovaries gradually stop producing progesterone and oestrogen, leading to hormonal imbalances. HRT replenishes these hormones, relieving symptoms and providing health benefits, such as protecting against osteoporosis.
For women who still have their uterus, HRT typically includes both oestrogen and progesterone (or a synthetic form known as progestogen). This is because oestrogen on its own can cause the uterine lining to thicken, increasing the risk of endometrial cancer. Adding progesterone counters this effect by promoting the shedding of the lining, much like in a natural menstrual cycle.
Women who have undergone a hysterectomy, however, may be prescribed oestrogen-only HRT since there is no risk of endometrial cancer in the absence of the uterus.
Types of Progesterone Used in HRT
There are different types of progesterone and progestogens used in HRT, each with distinct properties. These include:
Natural Micronised Progesterone: This type of progesterone is bioidentical, meaning it is chemically identical to the progesterone naturally produced by the body. Micronised progesterone, often sold under the brand name Utrogestan, is favoured by many women as it is generally well-tolerated and associated with fewer side effects than synthetic progestogens. It is commonly available in oral capsule form, but it can also be used vaginally.
Synthetic Progestogens: Also known as progestins, synthetic progestogens are chemically altered versions of natural progesterone. These include:
Norethisterone
Medroxyprogesterone acetate (MPA), found in products like Provera
Levonorgestrel, used in certain types of intrauterine devices (IUDs) like the Mirena coil
Synthetic progestogens are effective in protecting the uterus, but they may cause more side effects than natural progesterone, such as bloating, mood changes, or breast tenderness.
Vaginal Progesterone: Progesterone can also be administered vaginally, particularly for women who experience side effects from oral or synthetic forms. Vaginal progesterone is often used in the form of pessaries, creams, or gels. It is generally well-tolerated and may result in fewer systemic side effects since it is absorbed locally.
Progesterone and Histamine Reduction
An often-overlooked benefit of progesterone is its role in reducing histamine response, which is particularly relevant for women who experience symptoms of histamine intolerance, such as headaches, skin flushing, hives, or digestive issues. Histamine is a compound involved in immune responses and acts as a neurotransmitter, but excessive histamine can cause allergic-like symptoms or worsen conditions such as migraines and asthma.
Oestrogen can increase the activity of mast cells (the cells that release histamine), leading to higher histamine levels in the body. In contrast, progesterone helps balance this by reducing the production of histamine and supporting the body’s natural breakdown of it.
This is why some women find that their histamine-related symptoms improve during the luteal phase of their menstrual cycle, when progesterone is naturally higher.
For women on HRT, balancing oestrogen with adequate progesterone can help mitigate an excessive histamine response. This balancing effect can relieve symptoms for those who experience oestrogen-induced histamine intolerance, which can worsen during perimenopause or menopause when hormone fluctuations are common.
Progesterone Intolerance
While progesterone is essential in HRT, some women experience what is known as progesterone intolerance. This condition occurs when the body reacts negatively to progesterone or progestogen, leading to a range of physical and emotional symptoms.
Common signs of progesterone intolerance include:
Bloating
Breast tenderness
Fatigue
Irritability or mood swings
Depression
Headaches or migraines
In some cases, women experience symptoms similar to premenstrual syndrome (PMS) while on HRT, which can affect their quality of life. Progesterone intolerance can be challenging to diagnose, as symptoms may overlap with other conditions or the natural effects of menopause.
Managing Progesterone Intolerance
If progesterone intolerance is suspected, it’s important to speak to a healthcare professional, who may adjust the type or dosage of progesterone used in HRT. Some women find that synthetic progestogens, such as norethisterone or medroxyprogesterone, are more difficult to tolerate than natural micronised progesterone. Switching to a different form of progesterone, such as bioidentical micronised progesterone, may reduce symptoms.
In certain cases, we may recommend using alternative routes of administration, such as vaginal progesterone, which can result in fewer side effects compared to oral formulations.
The Benefits of Progesterone
Despite the potential for intolerance, progesterone offers numerous benefits beyond its use in HRT:
Supports Bone Health: Progesterone works with oestrogen to support bone density and protect against osteoporosis, a condition that weakens bones and increases the risk of fractures.
Balances Oestrogen: Progesterone helps regulate oestrogen levels in the body, reducing the risk of oestrogen dominance, which can cause symptoms such as weight gain, anxiety, and breast tenderness.
Reduces Histamine Response: By counteracting the histamine-increasing effects of oestrogen, progesterone helps alleviate histamine-related symptoms such as headaches, allergies, and digestive discomfort.
Promotes Healthy Sleep: Progesterone has a calming effect on the brain and can help improve sleep quality, especially in women who experience insomnia during menopause.
Boosts Mood: In addition to its role in physical health, progesterone can have a positive effect on mood by supporting neurotransmitters such as serotonin, which influences feelings of happiness and well-being.
Improves Skin Health: Progesterone is believed to help maintain skin elasticity and hydration, contributing to a more youthful appearance.
Conclusion
Progesterone is a crucial hormone with far-reaching effects on women’s health, especially during menopause. Its role in HRT is essential in protecting the uterus and alleviating many of the unpleasant symptoms associated with hormonal changes. By reducing histamine response, progesterone can also provide relief for women suffering from histamine intolerance. However, some women may experience progesterone intolerance, which can be managed with medical guidance. Understanding the benefits, challenges, and different types of progesterone can help women make informed decisions about their health and well-being during the menopausal transition.
Speak to one of our Menopause Specialists to help support your health.