In the present case, we were able to demonstrate primary abdominal pregnancy according to Studdiford's criteria with the use of transvaginal and transabdominal ultrasound examination and MRI. In our case, both fallopian tubes and ovaries were intact. With regard to the second criterion, we did not observe any uteroplacental fistulae in our case. Since abdominal pregnancy at less than 20 weeks of gestation is considered early [9], our case can be regarded as early, and so we dismissed the possibility of secondary implantation.
The recent use of progesterone-only pills and intrauterine devices with a history of surgery, pelvic inflammatory disease, sexually transmitted disease, and allergy increases the risk of ectopic pregnancy. Our patient had not been using any contraception, and did not report a history of the other risk factors.
The clinical presentation of an abdominal pregnancy can differ from that of a tubal pregnancy. Although there may be great variability in symptoms, severe lower abdominal pain is one of the most consistent findings [10]. In a study of 12 patients reported by Hallatt and Grove [11], vaginal bleeding occurred in six patients.
Ultrasound examination is the usual diagnostic procedure of choice, but the findings are sometimes questionable. They are dependent on the examiner's experience and the quality of the ultrasound. Transvaginal ultrasound is superior to transabdominal ultrasound in the evaluation of ectopic pregnancy since it allows a better view of the adnexa and uterine cavity. MRI provided additional information for patients who needed precise diagnosing. After the diagnosis of abdominal pregnancy became definitive, it was essential to determine the localization of the placenta. Meanwhile, MRI may help in surgical planning by evaluating the extent of mesenteric and uterine involvement [12]. Non-contrast MRI using T2-weighted imaging is a sensitive, specific, and accurate method for evaluating ectopic pregnancy [13], and we used it in our case.
Removal of the placental tissue is less difficult in early pregnancy as it is likely to be smaller and less vascular. Laparoscopic removal of more advanced abdominal ectopic pregnancies, where the placenta is larger and more invasive, is different [14]. Laparoscopic treatment must be considered for early abdominal pregnancy [15].
Complete removal of the placenta should be done only when the blood supply can be identified and careful ligation performed [11]. If the placenta is not removed completely, it has been estimated that the remnant can remain functional for approximately 50 days after the operation, and total regression of placental function is usually complete within 4 months [16].
In conclusion, ultrasound scanning plus MRI can be useful to demonstrate the anatomic relationship between the placenta and invasion area in order to be prepared preoperatively for the possible massive blood loss.