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Ectopic pregnancy is a leading cause of maternal mortality. A high index of suspicion of an ectopic pregnancy must be borne in mind, especially when a woman of reproductive age presents to the emergency department with abdominal pain and a positive pregnancy test. An ectopic pregnancy can occur in unusual sites, particularly when assisted reproductive techniques have been used. Most ectopic pregnancies occur in the fallopian tube (so-called tubal pregnancies), but implantation can also occur in the uterine cornua, cervix, ovaries, and abdomen, including the retroperitoneum. We present only the second reported case of ovarian ectopic pregnancy in a 37-year-old woman following an in vitro fertilisation and embryo transfer for bilateral salpingectomies.
Ovarian ectopic pregnancy (OEP) following in vitro fertilisation and embryo transfer (IVF-ET) in a patient with previous bilateral salpingectomies is extremely rare. This report highlights not only the increasing incidence of OEP following IVF but also the fact that bilateral salpingectomies do not prevent such ectopic pregnancies. Furthermore, the pathophysiological mechanisms for the possible occurrence of OEP, including the previously unreported tubal stump fistula, are also discussed.
A 37-year-old woman with bilateral salpingectomies for two previous ectopic pregnancies in 2001 and 2004 underwent IVF-ET. She presented to the accident and emergency (A&E) department on day 36 post-ET complaining of right iliac fossa and suprapubic pain. Urine β human chorionic gonadotrophin (β-HCG) was positive. An initial diagnosis of a possible right sided ovarian torsion was made by the A&E department and the patient was referred to the on call gynaecology team. Serum β-HCG concentrations were 110149 mIU/ml. Transvaginal scan carried out showed a gestation sac and fetus equivalent to 10 weeks gestation within the borders of the right ovary. Fetal heart movements were seen and the corpus luteum was present in the right ovary. In addition, free fluid was seen in the pelvis and abdomen suggestive of haemoperitoneum. In view of the diagnosis of a ruptured right ovarian ectopic pregnancy (fig 1), the patient gave informed consent for a laparoscopy and was operated on the same day.
At laparoscopy, there was a significant haemoperitoneum. Dense bowel adhesions from the previous Pfannanstiel incision for salpingectomies made the lower half of the abdomen inaccessible, and neither ovaries nor the uterus could be visualised via the laparoscope. Laparotomy was thus performed though a midline incision. Dense adhesions resulted in an inadvertent injury to the sigmoid colon. Once the extensive bowel adhesions were released, a right ruptured ovarian ectopic pregnancy was identified, with tubal stump adherent to the ovary which had a fistulous communication. A wedge resection of the ovary and removal of the tubal stump was carried out. A section of sigmoid colon was resected and a colostomy was performed. Seven units of packed red cells were transfused during the procedure. The initial postoperative recovery was in the intensive care unit. The patient was eventually discharged on day 8 after surgery with falling HCG values.
Ectopic pregnancy is a well known and an undesirable risk of IVF. IVF is often carried out in patients with pelvic pathology such as pelvic inflammatory disease (PID) or previous tubal surgery. These mechanical factors increase the risk of subsequent ectopic pregnancy following IVF. The proportion of ectopic pregnancies after IVF ranges from 4–11% of pregnancies.1
OEP is a rare form of extrauterine ectopic pregnancy, accounting for only 1–3% of all ectopic pregnancies.2,3 There has been only one prior case report of an OEP in a patient who had undergone bilateral salpingectomy before IVF-ET to improve pregnancy rate.4 Specific risk factors for an OEP differ slightly from tubal ectopics in that PID and previous tubal damage are not seen as being important, but intrauterine device (IUD) use remains important.5
Due to its rarity, no definite mechanism has been established for the development of an OEP. It has been hypothesised that the most likely reason is due to reverse migration6 of one of these embryos from an IVF-ET procedure towards the fallopian tube and subsequent implantation in the ovary.7 It was also suggested that increased volume and pressure of culture medium injected into the uterus or the tilt-down position of the patient at the time of ET could be contributory factors for the development of OEP.7 It has also been noted that fifth day blastocyst transfer has been associated with increased incidence OEP in women with no other predisposing factors for ectopic pregnancy.8 Difficult embryo transfers have also been postulated for OEP as these are thought to promote strong junctional zone contractions.9 Perforation of the uterus at the time of the embryo transfer could also result in an OEP due to the transabdominal migration of the embryos.
The only previous case report on OEP in a patient with previous laparoscopic bilateral salpingectomies suggested that a cornual fistula was the likely aetiology.4 The authors suggested that use of electrocauterisation for dissection of fallopian tubes can result in reduced blood supply and poor healing at the utero-cornual region, leading to tissue necrosis and the formation of a cornual fistula.4 As most salpingectomies are either partial or segmental with the possible aim of future tubal reconstructive surgery in mind, this unfortunately is increasing the risk of subsequent ectopic pregnancies including ovarian from IVF. In our case the right sided tubal stump had formed a fistulous communication with the right ovary by becoming adherent to it and this probably resulted in the ovarian pregnancy.
First line management of OEP is surgical. If possible, ovarian wedge resection is preferred in order to maintain ovarian tissue and function. Occlusion of the cornual ends and removal of any tubal attachment from the ovary are possible ways of decreasing the incidence of OEP.10
A high index of suspicion for ectopic pregnancy including OEP is warranted in patients undergoing IVF-ET despite bilateral salpingectomies. Despite only one similar case being previously reported, the increase in use of IVF is likely to lead to increased and unusual ectopic pregnancy presentations; it is therefore vital to consider the diagnosis early to prevent subsequent morbidity and possible mortality. Reverse migration along with a fistulous communication could be the combined aetiological cause for such unusual ectopic pregnancy sites.11
Competing interests: None.
Patient consent: Patient/guardian consent was obtained for publication.