For decades doctors and IC patients alike have speculated the role of hormones in developing IC and/or triggering its symptoms. Female patients report varying yet often predictable pain at different points in their menstrual cycles. And since there are significantly more female IC patients than male patients, estrogen merits attention. Understanding how estrogen impacts IC symptoms at times of the month when it is lower or higher or once levels are lowered in menopause can help patients manage their IC symptoms better.

Estrogen and Mast Cells

Mast cells, which the body needs to heal wounds and defend against pathogens, have been found in many bladders of IC patients. They are most known for their role in allergies, because too many mast cells cause problems. In fact, mast cells are what the immune system uses to induce inflammation to help with healing.(1) That’s all well and good except for when those cells misfire and increase inflammation even without an injury. Mast cells in bladders mean more inflammation even if there is no reason for it. Too many mast cells cause problems.

Dr. Theoharis Theoharides, who has spent years studying mast cells including their role in IC, said higher levels of estrogen can make mast cells fires more often which can cause more bladder discomfort for IC patients. Estrogen binds to mast cells and can cause issues. And this could be why many IC patients report higher levels of pain during ovulation since estrogen triggers ovulation and possibly more mast cells.

Tracking your cycle is a good idea. If you can identify times during your monthly cycle when you are more likely to flare — like during ovulation — then you can know what times of the month to work to prevent flares by monitoring food, stress levels and any other triggers more closely.

Estrogen and Pregnancy Remission

While we might be inclined to think that the remission of IC symptoms some women experience during pregnancy is hormone related, it most likely doesn’t have so much to do with hormones. Theoharides thinks pregnancy remission is more because the body initiates a response so the mother’s body doesn’t reject the fetus. Basically, the change in the immune system is most likely what causes the remission some patients experience.

And it turns out that IC patients aren’t the only ones who can experience remission during pregnancy. Theoharides said patients with other autoimmune diseases like irritable bowel syndrome and fibromyalgia are also prone to experience a remission of symptoms during pregnancy.

Estrogen and the Bladder Lining

Another way estrogen may impact IC symptoms happens later on in life when women enter menopause and their estrogen levels lower. Even non-IC patients can have some bladder symptoms in menopause such as urinary frequency, urgency and pressure/pain. This is thanks to the lower levels of estrogen impacting the bladder wall. With less estrogen, mucus membranes in the bladder become dry and more sensitive.(2)

Women who are menopausal can assume that if the skin on the outside in their personal area is dry then the inside is as well. And that could be contributing to their IC symptoms. Topical estrogen therapy can help, but so can many OTC products designed to add moisture. The ICN Shop carries a variety of helpful products for this that are also IC friendly.(2)

For premenopausal women, a study in 2018 from the Stratton Medical VA Center, found in a small study that the changes in estrogen levels throughout a usual monthly menstrual cycle affect the bladder smooth muscle and the mucosal blood flow in the bladder — all of which could contribute to IC symptoms.(3)

Estrogen and Nerve Endings

Along with all of the other things it does, estrogen also plays a role in nerve endings and pain. For example, prior to puberty, boys and girls have the same likelihood of developing chronic pain conditions, but after puberty, women are two to six times more likely to develop a chronic pain condition than their male counterparts.(4) And the increase of estrogen in females is one of the major differences during that time period.

Theoharides said hormones definitely affect sensitivity to pain. In general, pain increases when estrogen levels are low and progesterone levels are high. And estrogen levels are at their highest during pregnancy and childbirth, which could explain some of the decrease in symptoms during pregnancy.(4)


  1. Wikipedia. Mast Cell.
  2. Osborne J. Genitourinary Syndrome of Menopause (GSM) & Estrogen Atrophy Common In IC patients. IC Network.
  3. Levin R, et. al. Cyclical Estrogen as a Major Etiology of Interstitial Cystitis: A Theory and Review. Journal of Urology and Renal Diseases. Oct. 10, 2018.
  4. Staff. The Science Behind Why it is More Painful to be a Woman. Aug. 13, 2018.