Summary
This is a rare case of Caesarean scar ectopic pregnancy (CSEP) in a 31 year old gravida 2 Parity 2+0 who presented with amenorrhea for over one month and vaginal bleeding .She has delivered her first child by emergency caesarean section ten years ago in Thailand for failure to progress. The CSP was diagnosed early by ultrasound and timely laparotomy was done with favourable outcome although hysterectomy has to be done.
Background
Caesarean scar ectopic pregnancy (CSEP) is a rare type of ectopic pregnancy where the gestational sac is implanted in the myometrium at the site of previous caesarean section scar. The gestational sac must be completely surrounded by myometrium and fibrous tissues of the caesarean section scar and separated from endometrium cavity and endocervical canal. CSEP are associated with uterine rupture, massive bleeding and fatal complications. CSEP may lead to hysterectomy and subsequent infertility. The possible incidence of this type of ectopic pregnancy ranges from 1/1800 to 1/2200 pregnancies. However the incidence is increasing with increasing caesarean section rates in the past few decades.
CSEP may also follow previous hysterotomy for any cause, uterine manipulation and in vitro fertilization. Fortunately, the use of first trimester ultrasound has led to early diagnosis and timely management.
The pathophysiology of caesarean scar pregnancy remains to be established, but it is possible that the conceptus penetrates the myometrium through a microscopic dehiscent tract of the caesarean scar or the gestational sac implantation occurs in a poorly healed caesarean section scar. It may also result from a defect in the endometrium caused by trauma created by procedures in assisted reproduction techniques. The natural history of this condition remains unclear; it may the result in a pregnancy that loses its vascular connections while growing, thus causing a spontaneous abortion, or it may continue to grow gaining new stronger vascular connections ending into a low-lying adherent placenta with or without invasion of surrounding organs.
There are two recognized types of CSEP. Type 1 develops in the myometrium and grows towards the uterine cavity whereas type 2 progresses exophytically toward uterine serosa Type 2 pregnancies have ominous prognosis as they may lead to uterine rupture, haemorrhage, maternal death and loss of fertility due to the requirement for hysterectomy.
Early diagnosis and timely intervention is thus important to avoid serious complications. The most common symptom are pelvic pain and vaginal bleeding in first trimester. Many women are asymptomatic. Since there is no specific clinical sign of the CSEP, transvaginal ultrasonography and color flow Doppler are essential for diagnosis. TVS must be combined with transabdominal scan for panoramic view. In equivocal cases, Magnetic resonance imaging (MRI) will confirm or refute the diagnosis. Laparoscopy and hysteroscopy can miss the diagnosis due to presence of adhesions but MRI can be a helpful adjunct.
Case Presentation
A 31 year old female, gravida 2 parity 1 +0 was admitted to Tacheleik District Hospital with amenorrhoea for one month and bleeding per vagina for two days. Urine for UCG was positive. Her ten year old child was delivered by emergency caesarean section for failure to progress in Thailand. On examination, she has no pallor and vital signs were stable. Her abdomen was soft, not tender and no mass, no free fluid was detected. On vaginal examination, cervix was soft with slight excitation pain. Uterus was bulky and culs and POD were clear. There was blood stained discharge on VE fingers.
Urgent ultrasound abdomen and pelvis and transvaginal scan revealed empty but bulky uterus with adnexal mass in anterior uterine wall. There was a fetal pole without fetal cardiac activity in the mass. There was no free fluid. The diagnosis of ectopic pregnancy was made. Counseling was done and consent for laparotomy including the possibility of laparotomy was taken.
At laparotomy, the uterus was found to be enlarged with a brownish rounded mass of 7 cm by 7 cm on the left side of anterior wall of uterus behind the bladder at the lower segment scar area. This mass also extends into left broad ligament. The fallopian tubes and both ovaries were normal. Adhesiotomy between the mass and the bladder was done and total abdominal hysterectomy was done. Specimen showed CSEP with gestational sac and fetus on the left side of old ceasarean section scar. Postoperative period was uneventful and the patient was discharged from the hospital on the 6th postoperative day.
Figure 1 and 2
TVS scan showing thin endometrial lining in sagittal view. No intrauterine gestational sac was seen. A thick walled gestational sac with small fetal pole was noted in anterior isthmic portion of the uterus located in the scar area. There is no myometrial tissue between the gestational sac and the bladder. The CRL of 13mm indicates a 7 week+ 4 days gestation. No fetal cardiac activity detected. Findings included: the cervix was normal and the os was closed; both ovaries are normal and culs and POD are clear with no free fluid. Impression: a non-viable 7 week caesarean scar ectopic pregnancy/
Figure 3
Laparotomy photo of Caesarean scar pregnancy showing the gestational sac in lower uterine segment at the scar area adhered to the bladder
Figure 4
Cut section of the Caesarean scar pregnancy sac with placenta tissue inside
Discussion
Caesarean scar pregnancy is a rare type of ectopic pregnancy associated with severe complications such as uterine rupture, uncontrollable bleeding which may lead to hysterectomy, and definitive infertility.
Early diagnosis and timely intervention is thus important to avoid serious complications. The most common symptom is painless vaginal bleeding following amenorrhea and the bleeding may be massive. There can be internal bleeding in cases of uterine rupture. The urine UCG test and serum beta HCG test will be positive. Since there is no specific clinical sign of the CSEP, transvaginal ultrasonography and color flow Doppler are essential for diagnosis. In this case, the Urine UCG was positive and TVS was done.
The sonographic criteria for diagnosis are: (i) empty uterus and empty cervical canal; (ii) development of the sac in the anterior wall of the isthmic portion; (iii) a discontinuity on the anterior wall of the uterus demonstrated on a sagittal plane of the uterus running through the amniotic sac; (iv) absent or diminished healthy myometrium between the bladder and the sac; (v) high velocity with low impedance peri-trophoblastic vascular flow clearly surrounding the sac is proposed in Doppler examination.
Miscarriages (Abortion and missed abortion) and cervicoisthmical pregnancies can be sources of confusion in the diagnosis of CSEP. Ultrasonography is a precious diagnostic instrument to differentiate these conditions. The differentiating points between CSEP and cervicoisthmical pregnancy include the absence of healthy uterine tissues between the sac and the bladder.
Few gynaecologists have confronted CSEP and these few were confronted with a management dilemma, either continues the pregnancy, which would expose the mother to increased risk of heavy bleeding or terminate the pregnancy. The choice of management depends on the gestational age of pregnancy, the condition of the fetus, the patient’s condition and her choice. If termination is the choice, what is the most effective method?
Because of the rarity of CSEP, there are no optimal lines for therapy. Treatment modalities are either medical or surgical and are sometimes combined. The surgical approach includes radical and conservative procedures. The radical procedure consists of hysterectomy when the uterus is ruptured or if bleeding is uncontrollable.
The conservative procedures includes evacuation of early pregnancy by Manual vacuum evacuation (MVA) or Dilatation & Curettage under ultrasound guidance, excision of trophoblastic tissues and repair of uterine defect by laparotomy or laparoscopy. Other procedures include: locally and/or systemically administered Methotrexate, bilateral internal iliac artery ligation with curettage and more recently uterine artery embolization combined with curettage under ultrasound guidance. The use of Methotrexate sometimes requires laparotomy later because of severe hemorrhage and systemically delivered Methotrexate needs a prolonged follow-up. A hysterectomy was done in this case as the ectopic sac was large and encroaching in the entire lower segment.
Conclusion
CSEP poses a diagnostic and management dilemma to clinicians. High index of suspicion and awareness is essential. A missed diagnosis and delayed management may lead to uterine scar rupture, massive haemorrhage and maternal death. Transvaginal scan (TVS) equipment with Doppler and trained personals should be available in district hospitals.
Take home message
The incidence of CSEP is increasing nowadays due to rising caesarean section rate. Diagnosis is mainly by TVS and MRI can be a useful adjunct. Management is based on the patient’s condition, the viability of the fetus, the facility and expertise available. It can be managed conservatively by medical or surgical methods or combined by suction curettage or methotrexate injection followed by dilatation and curettage. Surgical management can be either radical or conservative surgery. These patients are of reproductive age and conservative management should be the aim if possible.
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