Progesterone plays a crucial role in the lifespan of a woman, serving as the "nurturing hormone." Its main functions are to signal the uterus to prepare a lining of tissue for a fertilized egg, support pregnancy, and promote the development of mammary glands (breasts).
During a woman's reproductive years, progesterone is produced by the ovary after ovulation, which occurs when an egg is released. If the egg is not fertilized, progesterone levels decrease, leading to menstruation. This cyclic process continues until menopause, which marks the end of ovulation and subsequently the end of progesterone production.
Menopause is a natural phase in a woman's life, signaling the end of her reproductive years. While it is a normal transition, it can bring various physical and emotional changes due to hormonal fluctuations. The most common symptom of low progesterone is periods becoming irregular, heavier, and longer during perimenopause.
There is clear evidence to support relief of symptoms with hormone therapy (HT), as well as its role in quality-of-life improvement, prevention of coronary heart disease, osteoporosis and fracture risk, and reduction in mortality. No other treatments for menopausal symptoms have demonstrated a similar role.
As women's health specialists, we strive to provide the best care and guidance during this crucial phase. In this blog post, we'll explore the role of progesterone in perimenopause and menopause, based on the latest position statement from the Menopause Society.
The Importance of Progestogen Dosing and Endometrial Protection
The primary role of progestogen in postmenopausal hormone therapy is endometrial protection. If you still have a uterus, unopposed estrogen therapy (ET) is associated with a significantly increased risk of endometrial hyperplasia and adenocarcinoma. Adding the appropriate dose and duration of progestogen to ET has been shown to lower that risk to the level found in never-users of ET.
One of the critical concerns during menopause hormone therapy is the risk of endometrial neoplasia (abnormal tissue growth in the uterine lining). The Menopause Society position statement emphasizes that progestogen dose and duration of use play a vital role in ensuring endometrial protection when combined with systemic estrogen.
Studies conducted by the Women's Health Initiative (WHI) have shown that the use of continuous oral conjugated equine estrogens (CEE) combined with medroxyprogesterone acetate (MPA) daily does not increase the risk of endometrial cancer when compared to placebo. In fact, there was a significant reduction in risk after a median follow-up of 13 years.
It is important to note, the use of progesterone is not necessary if you 1. have had a hysterectomy or 2. are only on local vaginal estrogen therapy for genitourinary syndrome of menopause. Vaginal estrogen is not systemically absorbed.
Different Progesterone Dosing Regimens
The Menopause Society statement acknowledges that different progestogen dosing-regimens are available to provide endometrial safety, depending on the potency of the progestogen and the estrogen dose.
Continuous Combined Regimen: This regimen involves taking both estrogen and progestogen continuously, which has not been associated with an increased risk of endometrial cancer.
Sequential Regimen: In this approach, progestogen is given for a certain number of days each month, typically 12-14 days. It's important to ensure adequate dosing to prevent endometrial hyperplasia, an abnormal thickening of the uterine lining.
Oral progesterone is the route of preference because the molecule is large and not absorbed transdermally – no compounded creams. Progesterone should be taken at bedtime as it has a sedative effect and can help with menopausal insomnia.
The formulation of progesterone available for Hormone Therapy (HT) includes distinct types of progestogens, each with its unique biological and clinical characteristics. These progestogens can be either synthetic progesterone, which has a different structure than naturally occurring progesterone, or natural micronized progesterone (MP). Developed in the 1980s, MP is derived from the yam plant. One of the key advantages of MP is that it is chemically and structurally identical to human progesterone, earning it the terms bio-identical or 'body identical’. This similarity allows for better compatibility with the body's natural processes, making it a favorable choice for many women.
Benefits and Considerations
Hormone therapy, including estrogen and progestogen, can effectively manage menopause symptoms such as hot flashes, night sweats, and mood swings. Moreover, some women prefer regimens that avoid periodic menstrual bleeding, and patient preference should be taken into account when deciding the dosing regimen.
It's natural to have questions or concerns about hormone therapy, especially related to the risk of endometrial cancer. A systematic review suggested a potential increase in the risk of endometrial hyperplasia with estrogen plus progestogen therapy, particularly with noncontinuous combined regimens. However, it's important to note that continuous combined therapy did not show an increased risk. Women who experience unscheduled bleeding more than six months after starting estrogen and progestogen therapy should promptly seek medical investigation.
For women who prefer a localized progestogen option, an intrauterine device (IUD) containing levonorgestrel can be considered. It may help prevent endometrial hyperplasia while avoiding some of the systemic side effects of progestogens. However, the use of IUDs for this purpose is still considered off-label, and clinical trial data supporting this use are limited.
As OBGYNs, our primary goal is to support women through every stage of life, including perimenopause and menopause. The Menopause Society position statement emphasizes the significance of progestogen dose and duration in ensuring endometrial protection during hormone therapy. By understanding the benefits and risks associated with different progesterone dosing-regimens, we can work together with our patients to make informed decisions tailored to their individual needs and preferences. If you have any questions or concerns about menopause hormone therapy or any other women's health issues, don't hesitate to reach out to us at Sky Women's Health. We're here to provide the best care and support for your well-being.
Disclaimer: This blog post is for informational purposes only and should not be considered a substitute for professional medical advice. Always consult with a qualified healthcare provider for personalized guidance and recommendations regarding menopause hormone therapy.