Obstructed mullerian duct anomalies are defects in the development of the reproductive system that are present in a female baby before birth. Mullerian ducts are the early structure within an embryo that develop into a female's reproductive organs including Fallopian tubes, uterus, uterine cervix and part of the vagina. Sometimes defects block the duct (channel) through which blood should flow out of the body during monthly menstruation.
Obstructed mullerian duct anomalies can cause blood to collect in the uterus and the vagina, instead of flow out of the body. The disorder increases the likelihood of retrograde menstruation (when the blood, instead of flowing out of the body, flows backward through the Fallopian tubes and into the pelvis.)
Patients with obstructed mullerian duct anomalies often have functioning ovaries and age-appropriate external genitalia. As a result, these abnormalities are often not recognized until after puberty begins.