Definition: Abdominal pregnancy is a form ectopic pregnancy, located in the peritoneal cavity, excluding the ovarian and intraligamentary pregnancy. The placenta is frequently inserted on the bowel, omentum, utero-vesical recess and pelvic wall. Rare places including the mesenteric, bladder wall, appendices and liver may occur.
Incidence: 1:10.000 births and 1:100 of the ectopic pregnancies.
Etiology: It is a rare complication of ectopic pregnancy, usually due to an abnormal implantation or a rupture of an ectopic pregnancy in the abdominal cavity.
Risk factors: Pelvic infection disease (Chlamydia trachomatis), smoke, previous pelvic surgery, previous ectopic gestation, intrauterine device.
Clinical presentation: Clinical history of recurrent episodes of abdominal pain, vaginal bleeding and gastrointestinal symptoms are the first clue for the correct diagnosis, associated with abnormal fetal presentation.
Complications: The most serious complications include severe hemorrhage due to intravascular disseminated coagulation and infection with abscess formation.
Diagnosis: Ultrasound and more recently MRI have facilitated the early and correct identification of the ectopic pregnancy. The visualization of an empty uterine cavity with an abdominal mass that includes the fetus, but without amniotic fluid or myometrium around are the most suggestive signs. Besides the capability to differentiate organs and structures based on their characteristic signs, MRI allows a correct diagnosis and the right location of the fetus and placenta.
Prognostic: The abdominal pregnancy is associated with high maternal (0-20%) and perinatal (40-95%) mortality. Maternal mortality is about 5.1:1.000 compared with 0.7:1.000 in other ectopic gestation"s. The perinatal mortality has been traditionally high. However recent progresses have result in a 70-80% increase in the survival in fetuses older then 30 weeks. More than 90% of the survivors have serious malformations.
Conclusions: Mortality and maternal morbidity are directly related to the removal of the placenta during childbirth. The remove of the placenta depends on the degree of invasion, the location of insertion, the involvement of the other organs and the surgical access to the placental blood supply. If it is possible, the complete placental extraction should be done. If not, the placenta should be left at the place, following by occlusion of the umbilical cord. The subsequent management is expectant. The placental reabsorption can be accelerated with methotrexate, selective arterial embolization and secondary laparotomy.
References
ZAKI ZMS. An unusual presentation of ectopic pregnancy. Ultrasound Obstet Gynecol 1998; 11: 456-458
Hall JM, Manning N, Moore NR, Tingey WR and Chamberlain P. Antenatal diagnosis of barks her abdominal pregnancy using ultrasound and magnetic resonance imaging: marry her/it report of successful outcome. Ultrasound Obstet Gynecol 7 (1996) 289-292
Varma R, Mascarenhas L, James D. Successful outcome of advanced abdominal pregnancy with exclusively omental insertion. Ultrasound Obstet Gynecol 2003; 21: 192-194
BOUYER J, COSTE J, FERNANDEZ H, POULY JL AND JOB-SPIRA N. SITES OF ECTOPIC PREGNANCY: to 10 year population - based study of 1800 marry. Human Reprodution 2002; 17: 3224-3230
Bajo JM, Garcia-fruits the and Huertas MA. Sonographic follow-up of the placenta left in situ after delivery of the fetus in an abdominal pregnancy. Ultrasound Obstet Gynecol 7 (1996) 285-288