Unusual Clinical Presentation of Endometrial Changes on the Low Dose Oral Contraceptive Pill

Background Endometrial changes have been previously described in a small series of adult patients treated with high dose combination oral contraceptive pills. Cases #1. EC is a 16yo G0 who had menarche at age 13 and presented with a long history of irregular menses, menometrorrhagia, and anemia. At inital presenTation, her bleeding had increased to one pad/hr. and her hemalocrit was 15%. She was transfused and the bleeding stopped with LoOvral every 8 hrs. She was discharged home on LoOvral every 12 hrs. and iron. Two weeks after discharge, the LoOvral was decreased to one pill daily. Three weeks after discharge, she had some breakthrough bleeding and was told to take one pill twice a day. Two days later, she presented to the Emergency Department with severe spasmodic abdominal pain and vomiting. She was afebrile with stable vital. Of note, her WBC count was 12.1 with a normal differential. Her was 37%. and urine HCG was negative. Abdominal exam showed normal bowel sounds, significant guarding and diffuse abdominal pain to palpation. Bimanual pelvic exam revealed a uterus enlarged to twelve weeks size with an open cervical to that was filled with large amounts of pink-grey fleshy tissue. KUB, Ultrasound and CT scan were read as negative. With continued passage of tissue her symptoms resolved. She was admitted for observation and treatment of what was thought to be an incomplete spontaneoul abortion. However, she continued to deny sexual activity and her quantitative HCG returned negative. The pathology returned as decidualized endometrium with necrosis and chronic active inflammation, no chorionic villi were identified. The patient was discharged on cyclic LoOvral and iron and has had no problem over the last six months. #2. NC is a 12 yo G0 who initally presented to the Gynecology Program with menometrorrhagia since menarche at age 11. At presentation, she had a hematocrit of 35% and negative urine HCG. She was prescribed LoOvral and stopped bleeding with the first pill from the pack. On the first placebo pill, she started bleeding and developed increasing abdominal pain particularly in the LLQ that became severe and spasmodic. On presentation to the Emergency Department, her vital signs were stable, her abdomen was soft and with good bowel sounds but became rigid with the onset of waves of pain. A single digit pelvic exam was difficult and limited. An ultrasound was normal. Her WBC was 11.5, HCT was 37%. and BHCG was negative. The pain resolved with spontaneous passage of a large amount of pink fleshy tissue per the vagina. Pathology reported the tissue to be a decidualized endometrial cast. The patient has been doing well for the last three months on cyclic oral contraceptives. Conclusion It has been described that the high dose oral contraceptive pill suppresses the endometrium. When given 20 days of Enovid, the 25th day endometrial biopsy showed that the stroma was decidua like. With further formulations of the combined pill in which the progestin were decreased to 5 mg., the decidua like stromal reactions became weak and infrequent. In examining the continuous treatments with high dose oral contraceptives for endometriosis, samples from the endometrium exhibited diffuse, intense decidual reactions similar to that seen in the first and second trimesters of pregnancy. Both of our patients’ presentations are unique variations of this pathology. Both were on doses of combination oral contraceptives significantly lower than those previously described to cause such intense decidual changes. In addition, something caused the marked decidual changes to be expelled by the uterus. We hypothesize that anovulatory cycles had created an endometrium that was exposed to high doses of unopposed estrogen creating an intense decidual reaction and with the addition of a small amount of progestin in LoOvral, the endometrium was sloughed.