Women's Health Community

Dear aqminor: The easy part first, OK? It is very common for women using birth control pills (BCPs) to have a "period" which looks more like dark motor oil sludge than bright red menstrual bleeding. Here is the reason.

When the bleeding is brisk and heavy the blood flows quickly out of the uterus and vagina. When the bleeding is scant and slower it has a much longer time to be exposed to the oxygen in the air. This exposure will turn the blood color brownish. Think about a piece of meat which has been exposed to air for a while. The outside will be dark brown/gray. Yet when you cut into the meat, and expose an area which has not been in contact with the air, the color will be red.

The synthetic progesterone in BCPs creates a thinner lining inside the uterus. This creates a decreased amount of flow. This more scant flow will appear as a dark brown color, and thick consistency.

In terms of passing what look more like "tissue," most commonly, when we send such specimens to the lab, the report returns as: white blood cells, red blood cells, fibrin, and other components of uterine lining tissue. It can look different as it is more solid than the liver-like consistence of blood clots. Many women worry that this is linked to a missed miscarriage, but that is not the usual explanation. If this is a concern to you than a sensitive pregnancy test can be done.

VERY rarely a woman will pass a "uterine cast". This is when the lining is passed as a triangular shaped bit of tissue similar to the shape of the inside of the uterus. The predisposing condition for passing a uterine cast is abrupt cessation of high dose progesterone therapy. I have also seen a cast associated with an ectopic/tubal pregnancy.

If you have other symptoms or concerns you should contact your GYN. Saving the tissue to be sent to a lab is a possible option, but it is rarely done.

Thanks for writing about these menstrual symptoms.Life in "Pelvis World" is often graphic.

Yours,
Jane