Keywords : Intrauterine fetal bones ● Ultrasound ● Hysteroscopy
Retained fetal bones in the uterine cavity is rare subsequent to mid-trimester pregnancy termination, spontaneous intrauterine death and missed abortion. These patients may present with pelvic pain, dysmenorrhea, abnormal uterine bleeding and infertility.
A 35 year old P1 came to our outpatient department with complaints of pain in the lower abdomen and amenorrhea for 2 months following a surgical second trimester abortion. Her previous menstrual cycles were regular. She was a kidney recipient with well preserved renal function on receiving predorisolone, cyclosporine and azathioprine for 2 years; thyroxine 100mg daily, and an antihypertensive. Her general physical examination was were normal. Pelvic examination revealed a bulky uterus of 10 weeks size with bilateral forniceal tenderness. A transabdominal and transvaginal sonography detected bright intrauterine echoes suggestive of retained fetal skull and bones in the uterine cavity. Cervical ripening with 400mg moistened vaginal misoprostol was done followed by surgical evacuation. Few bony spicules were removed and subjected to a histopathological examination. The report revealed products of conception. The patient was sent home the next day but got readmitted 10 days later with acute pain in the lower abdomen. Transvaginal scan done at this visit showed retained bony fragments and a 4.2 x 3.8 cm left ovarian cyst. The patient was given put on intravenous ciprofloxacin and metronidazole for 72 hours and reinduced with vaginal misoprostol 400mg 3 hourly for a total of five doses, following which there was neither any bleeding nor expulsion of products. After taking a nephrology and anesthesia clearance, she was posted for a diagnostic hysteroscopy and laparoscopy under general anesthesia. On hysteroscopy, a number of bones including skull bones were found adherent to the right and left uterine walls above the isthmus. Bones were removed with difficulty from the uterus by a dilatation and curettage (Figure 1). The largest piece was 2x0.5 cm. Repeat hysteroscopy confirmed that the uterus was empty. By laparoscopy, the left ovarian cyst was punctured and 30mL straw colored fluid was drained. Histopathology revealed retained products of conception.
Retention of fetal bones in the uterus is a rare complication of abortion or following a removal of a macerated fetus. Roth and Taylor 1 hypothesized that without a previous pregnancy loss, metaplasia of mature endometrial stromal cells into bony tissue occurs in response to chronic inflammation or trauma. Prolonged retention of fetal bones might cause pelvic inflammatory disease (PID), chronic pelvic pain, infertility, menorrhagia, irregular bleeding, offensive vaginal discharge or passage of bony fragments vaginally. Taylor et al2 in a study of nine patients reported secondary infertility in seven, pelvic pain in one and passage of bony fragments in one. Sahinoglu3 described a case of postmenopausal bleeding and pelvic pain caused by prolonged retention of fetal bones after a midtrimester abortion 17 years since. Moon et al4 reported 11 cases in which retained fragments of fetal bones after second trimester abortion contributed to secondary infertility. A recent case report by Van den Bosch et al 5 shows that uterine intramural bone persisting after midtrimester termination of pregnancy may not affect fertility. Retained bony fragments cause infertility by acting like uterine synechiae or an intrauterine contraceptive device 6. The mechanism of poor fertility outcome is attributed to an increase in the local production of prostaglandins that prevent blastocyst implantation. Diagnosis can be made on transvaginal ultrasound and x-ray of the pelvis. Retained bony fragments may not always be visualized by hysterosalpingography. Hysteroscopy is an invaluable tool in both confirming the diagnosis and achieving its successful removal. Removal of the fragments by curettage, relieved her of pelvic pain symptoms. Women with complaints of pelvic pain or infertility with a past history of abortion should be evaluated by a transvaginal ultrasound to rule out the presence of intrauterine fetal bones. Hysteroscopy offers great help in identifying and treating such a case.
