Successful methotrexate treatment of a viable pregnancy within a thin uterine scar

Case report A 37 year old woman presented in her fourth pregnancy eight weeks of gestation with recurrent episodes of vaginal bleeding for seven days. Her first delivery was by a lower segment transverse caesarean section at 33 weeks of gestation due to pre-eclampsia. Her second and third pregnancies ended by a normal vaginal delivery. On admission her pulse and blood pressure were normal. Pelvic examination revealed moderate bleeding from the cervical canal; the cervix was long and closed. The size of the uterus was consistent with her dates. Transvaginal ultrasound demonstrated a live fetus with a crown-rump length of 19 mm equivalent to her menstrual dates. The gestational sac was 25 mm diameter which was located in the anterior wall of the uterus, just above the internal 0s. Only 4 mm thickness separated the sac from the urinary bladder, and the sac was located between two normal segments of the anterior uterine wall (Fig. 1). Based upon the ultrasound findings, a diagnosis of pregnancy in a very thin uterine scar was made. Following discussion, it was decided to terminate her pregnancy with methotrexate. A single dose of 80 mg (50 mg/m2) intramuscular methotrexate was given. Daily ultrasonography revealed loss of fetal heart beats three days following the injection. No adverse side effects were observed. Three days after the injection, the plasma level of the p subunit of human chorionic gonadotropin (p hCG) was 12,100 mIU/mL; it decreased to 1270, 107 and 20 mIU/mL after two, four and eight weeks, respectively. Despite the declining values of plasma p hCG levels, the patient had prolonged mild vaginal bloody discharge. Ultrasonography showed the same gestational sac containing amorphous tissue debris. Nine weeks after the methotrexate injection 10 ml of straw-like fluid was aspirated from the gestational sac by a transvaginal ultrasound guided needle, without any complications. Three months later transvaginal ultrasound showed complete disappearance of the gestational sac and normal uterine anatomy. Eight months after the