Progesterone and the Lymphatic System

June 3, 2025 Alannah Connealy

Progesterone & the Lymphatic System

The lymphatic system plays a crucial role in immune function, nutrient transport, and fluid balance. It collects excess fluid from tissues, filters it through lymph nodes to remove pathogens and waste, and returns it to the bloodstream. The lymphatic system also transports fats and fat-soluble vitamins absorbed from the digestive system, contributing to overall metabolic health.

Lymphatic vessels that run parallel to blood vessels and are found in nearly all tissues, including the skin, muscles, organs, and even within bones.

A free-flowing lymphatic system is essential for the circulation of progesterone throughout the body.

Lymphatic fluid is non-polar and has a strong affinity for fatty substances. Steroid hormones are generally hydrophobic, but as they progress along the steroid pathway from cholesterol (their parent fat), they become increasingly polar. Consequently, estrogen is more polar than progesterone, making progesterone more readily attracted to lymphatic tissue.

This property enables progesterone to more easily interact with lymphatic fluid, leading to elevated tissue levels when applied topically through superficial lymphatic vessels (PMID: 23652031).

Steroid hormones begin as fat-like substances and become more polar as they move through the steroid pathway. As a result, lymphatic tissue having a greater attraction to progesterone than estrogen.

The lymphatic system's involvement in progesterone bioavailability may explains the hormone’s protective role in pregnancy-related immune responses.

Elevated progesterone levels contribute to increased immune tolerance, which is facilitated by the action of progesterone-induced blocking factor (PIBF) produced by lymphocytes in lymphatic cells. This ensures that progesterone is available where it's needed to address infections and pathogens and protect the fetus during pregnancy.This same action may contribute to progesterone’s anti-cancer actions as well.

Interestingly, lymph stagnation is often associated with estrogen dominance.

Excess estrogen can affect lymphatic function by increasing vascular permeability and causing tissue edema. This can lead to fluid leaking out of the blood vessels and into the surrounding tissues, causing swelling. This excess fluid can inhibit lymph flow, as the lymphatic system struggles to remove this extra fluid efficiently.

Conversely, progesterone helps stabilize blood vessel walls, reducing their permeability and preventing excessive fluid leakage into surrounding areas. This action helps minimize tissue edema caused by increased vascular permeability from excess estrogen.

The lymphatic system may become stagnate due to:

Lack of physical activity
Dehydration
Poor posture
Emotional stress
Injury
Tight clothing / bras
Unaddressed underlying infections
Nutrient deficiencies
High toxin burden
Poor sleep

Natural progesterone is safe and often recommended for pregnancy. (We always recommend you consult with a trusted healthcare provider.)

Progesterone is the main hormone produced by the ovaries and is crucial for both fertility and maintaining pregnancy. In healthy pregnant women, progesterone levels in the blood increase each trimester, reaching as high as 300ng/mL by the third trimester!

Progesterone helps to remove excess estrogen from tissues & stabilize the uterine lining, ensuring successful implantation of the embryo and providing a favorable environment for the placenta to attach & grow. Progesterone keeps the mother’s immune system from attacking the baby by expanding regulatory T cell activity and reducing inflammatory cytokines. Progesterone’s relaxing effect also helps prevent early delivery by inhibiting uterine contractions.

The use of progesterone before and during pregnancy is associated with a reduced incidence of birth defects. It has been shown to relieve anxiety & depression, improve memory, protect brain cells, prevent epileptic seizures and even treat cancer. Low maternal progesterone levels have also been linked to autism.

Work by Dr. Katharina Dalton has shown that 50-300mg/day of progesterone administered to pregnant women (especially before 16th week) not only reduced pre-eclampsia & stillbirths, but increased the IQ scores of children later in life. These “progesterone babies” were found to have strong, serene, independent characters alongside their increased intelligence. A later follow up found that progesterone children were nearly 6 times more likely to attend college.

Natural, bioidentical progesterone should not be confused with progestins. Synthetic progestins are altered versions of bioidentical progesterone that pharmaceutical companies patent in order to increase profits, since natural hormones cannot be patented. Progestins are often found in hormonal birth control & hormone replacement therapy. Progestins carry risks that are not associated with natural progesterone, especially during pregnancy. Prenatal progestin exposure is associated with psychiatric disorders in children. In one study, 9 out of 10 girls whose mothers were treated with progestins had evidence of hermaphroditism. In animal models, progestins are capable of causing autism-like behaviors such as hyperactivity, anxiety and depression, while natural progesterone has been shown to prevent these same behaviors.