Cesarean section scar ectopic pregnancy is a rare complication of pregnancy, occurring in approximately 1 in 2000 pregnancies [1,2]. Its incidence is rising in parallel with the increase in primary and repeat cesarean sections. Globally, the incidence of primary cesarean section averages 18.6% of all births . A hysterotomy scar ectopic pregnancy has also been reported following myomectomy, uterine evacuation, previous abnormally adherent placentation, manual removal of placenta, metroplasty, hysteroscopy, andin vitrofertilization .
There are two recognized types of hysterotomy scar ectopic pregnancies. Type 1 develops in the myometrium and grows toward the uterine cavity, whereas type 2 progresses exophytically toward the uterine serosa . Type 2 pregnancies have an ominous prognosis because they may result in spontaneous uterine rupture, hemorrhage, and maternal death. There is potential for loss of fertility should massive hemorrhage necessitate a hysterectomy.
Symptoms include pelvic pain and vaginal bleeding in the first trimester. Many women are asymptomatic at diagnosis. The investigation of choice is transvaginal ultrasound (TVUS), which may be combined with a transabdominal scan for a panoramic view. In equivocal cases, magnetic resonance imaging (MRI) will confirm or refute the diagnosis .
Treatment modalities are dependent on the case presentation. Women have been managed expectantly, medically with methotrexate, or surgically [2,5]. Apart from surgical excision at hysteroscopy or laparoscopy or laparotomy, vacuum aspiration can be used to remove the ectopic scar . This case report aims to expose a diagnostic conundrum that clinicians might face. Cesarean scar ectopic pregnancies are a rare presentation that may be difficult to diagnose and for which a management option may be hard to choose.
We describe a case of a 36-year-old black African woman with two previous live births by cesarean section and two previous miscarriages who was referred in her fifth pregnancy after 6weeks of amenorrhea. Her serum quantitative -human chorionic gonadotropin (bHCG) was 16,124 mIU/ml. However, an intrauterine or extrauterine pregnancy could not be located on a transabdominal ultrasound scan.
A copper intrauterine contraceptive device had been removed 2months prior to her last menstrual period. She reported using one cycle of clomiphene 50mg with the hope of achieving a twin pregnancy.
She had delivered twice by cesarean section for failure to progress. Her last two pregnancies had been first-trimester miscarriages; one was managed expectantly, and the other was surgically evacuated, though the actual procedure was unknown to the patient. She did not have any chronic medical illness and was not receiving any medication prior to this presentation. She stayed in a city suburb that was well serviced. She was a school principal in her second marriage with no children in the current relationship. She did not smoke or drink alcohol.
On examination, she had a normal blood pressure of 113/70mmHg and a pulse rate of 98 beats/min. Her body temperature was 37.5 C. On examination, her cardiorespiratory and neurological systems were normal. Her abdomen was soft and not tender. The result of her pelvic examination was normal. TVUS showed a gestational sac of 13mm with irregular margins and a visible yolk sac located on the anterior isthmic portion of the uterus, raising suspicion of a cesarean section scar ectopic pregnancy. She declined a Doppler ultrasound evaluation scheduled for the next day. She was scheduled to have serial bHCG evaluations every 48h.
An emergency laparotomy was then performed on the same day. The abdomen was entered through a Pfannenstiel incision along the old skin scar. A transverse incision was made in the upper uterine segment just above the adherent bladder. The products of conception were removed with forceps, and the gap in the anterior myometrium at the old scar was seen and felt. There was massive bleeding from the implantation site. Twenty milliliters of vasopressin (20U diluted in 100ml) in normal saline was administered into the bleeding myometrium edges. The edges were apposed in layers with VICRYL suture (Ethicon, Somerville, NJ, USA) to repair the defect. Estimated blood loss was 2000ml. The patient was transfused with 1 U of packed cells intraoperatively. She was continued on the same intravenous antibiotics and analgesia that had been commenced after the laparoscopy. Her hemoglobin count on day 1 postoperatively was 8g/dl, and she declined any further transfusion. Oral iron and folic acid supplementation was commenced.
The patients postoperative recovery was uneventful, and she was discharged on day 4 after surgery. Histology confirmed the presence of decidua and chorionic villi. The patient wanted a child because she was in a new relationship, but she was no longer sure of her future fertility plans after the ectopic pregnancy. A levonorgestrel implant was inserted 2weeks postoperatively. The patient last attended physical review at 6weeks, and she was well with no problems related to the surgery at a telephone review at 3months postoperatively.
We present a case of a 36-year-old patient who had two previous cesarean sections and one previous surgical evacuation of the uterus. She presented initially with a pregnancy of unknown location, then suspected scar ectopic pregnancy followed by an inconclusive laparoscopy and hysteroscopy. She was then managed definitively by excision and repair of the myometrial defect following affirmation of uterine ectopic scar by MRI.
Though our patient had undergone three previous uterine procedures, one case series shows that most scar ectopic pregnancies occurred after only one cesarean section. Hence, the number of cesarean sections appear to have no impact as an independent risk factor [2,7].
It is known that pregnancy in the presence of an intrauterine contraceptive device is a high risk factor for ectopic pregnancies. There is no information on whether previous use of an intrauterine device is associated with a scar ectopic pregnancy.
As in our patients case, uterine scar ectopic pregnancies can pose a diagnostic conundrum. Our initial suspicion was raised at the time of TVUS. The differential diagnosis included cervical ectopic pregnancy, cervicoisthmic pregnancy, and inevitable miscarriage. Known diagnostic criteria for a cesarean section scar pregnancy are a gestational sac located anteriorly at the level of the internal os within a visible myometrial defect and functional trophoblast demonstrated on color Doppler imaging studies . The pelvic adhesions and intrauterine adhesions seen at laparoscopy/hysteroscopy made us lose confidence in the TVUS findings, until MRI affirmation.
Surgical excision was our treatment of choice because the pregnancy was extending exogenously, the fetus had active cardiac activity, and the bHCG levels at diagnosis were very high. Methotrexate has traditionally been reserved for the management of ectopic pregnancies with a bHCG value less than 5000 mIU/ml. Uterine artery embolization and expectant management are options for stable patients but require close follow-up to avoid potential disastrous consequences such as uterine rupture. Surgical treatment, successful in 96%, is the most definitive treatment option that removes the gestation and offers an opportunity to repair the uterine defect and a chance at future fertility [1,5,9]. Surgical excision can be achieved via laparotomy, laparoscopy, and hysteroscopy or vacuum aspiration , depending on the location of the gestation and the surgeons expertise, among other factors. We chose laparotomy because it would give us better access and control of hemorrhage in this situation of type 2 scar ectopic pregnancy. Despite a live birth rate of 57% in one systematic review, 63% of women managed expectantly required hysterectomy for the management of life-threatening hemorrhage following spontaneous uterine rupture or abnormally adherent placenta . The high morbidity and risk of death do not justify expectant management of a viable scar pregnancy.
The risk of recurrent scar ectopic pregnancy is low, 3.25.0% [2,10]. Women who intend to continue childbearing should be informed of the low risk of recurrence but the potential serious sequelae of a recurrence. Even with an intrauterine pregnancy, the woman is still at risk of complications of multiple hysterotomies, such as abnormally adherent placenta, uterine rupture, massive hemorrhage, and hysterectomy. Future pregnancies require meticulous specialist follow-up.
Uterine scar ectopic pregnancies pose a diagnostic challenge that calls for clinicians and radiologists managing women with associated risk factors to maintain a high index of suspicion during imaging and follow-up. A missed diagnosis with delayed management may lead to uterine rupture, massive hemorrhage, and maternal death. Transvaginal scanning equipment and training should be readily available even in resource-limited settings. A screening tool for evaluating at-risk patients and a protocol for escalating to MRI for equivocal cases should be available at the point of care.
- bHCG:-Human chorionic gonadotropin
- MRI:Magnetic resonance imaging
- TVUS:Transvaginal ultrasound scan