Abdominal pregnancy, a rare variant of ectopic pregnancy, is defined as the primary or secondary implantation and development of the conceptus, either partially or entirely, within the peritoneal cavity. Advanced or evolved forms beyond the fifth month are exceptional in developed countries but remain relatively more frequent in low-resource settings with limited access to prenatal care [1]-[5]. Primary abdominal pregnancy is uncommon, and progression to term is typically associated with high perinatal mortality. Due to inadequate prenatal follow-up, diagnosis is often delayed, limiting management options, which are predominantly surgical. Through the presentation of two cases of abdominal pregnancy with diverse modes of presentation, we aim to highlight the critical importance of first-trimester ultrasound screening, the diagnostic value of transvaginal sonography, and the potential role of magnetic resonance imaging (MRI) in cases with persistent diagnostic uncertainty [6].

Abdominal pregnancy is a rare complication of ectopic gestation, with an incidence of approximately 1 in 10,000 to 1 in 25,000 deliveries in developed countries [4]. In contrast, its prevalence is significantly higher in low-resource settings estimated at 1 in 2,000 deliveries due to limited access to prenatal care, delayed diagnosis, and high rates of genital tract infections [1][5][7]. This disparity is largely attributable to socioeconomic and healthcare system differences: while assisted reproductive technologies and intrauterine devices are common risk factors in industrialized nations [7]-[9].

In low-medical-resource settings, the diagnosis of abdominal pregnancy remains challenging, often made only intraoperatively in up to 50% of cases [2][5]. Although rare overall, abdominal pregnancy can be classified into two pathophysiological types: secondary and primary. Secondary abdominal pregnancy, the more common form, typically results from tubo-abdominal abortion, rupture of a tubal pregnancy, or migration through a uterine scar (e.g., following prior cesarean section). Primary abdominal pregnancy, by contrast, arises from direct implantation of the conceptus within the peritoneal cavity due to delayed oocyte capture a phenomenon rarely documented. In our two observations, the placenta was attached either to the uterine fundus and sigmoid colon or to the broad ligament and left ovary. For this reason, our patients can be diagnosed with a secondary abdominal pregnancy.

Prenatal diagnosis relies primarily on ultrasound. A key diagnostic criterion is the clear anatomical separation between the uterine wall and the gestational sac, with the placenta appearing distinct from the uterine myometrium [6][9][10]. Clinically, suspected abdominal pregnancy may present with nonspecific symptoms including nausea, vomiting, abdominal or pelvic pain exacerbated by fetal movements (if the fetus is viable), and occasionally vaginal bleeding. The fetus is often located superficially and in an atypical transverse position. On vaginal examination, the cervix may be fixed below the symphysis pubis, firm, and elongated. Laboratory findings may include maternal anemia and elevated alpha-fetoprotein levels [11][12].

Beyond the first trimester, both clinical and ultrasound diagnosis become increasingly difficult. In cases of diagnostic uncertainty, Ehab et al. recommend magnetic resonance imaging (MRI) to delineate the precise site of implantation by visualizing the entire uterine contour and surrounding structures [13]. MRI offers superior soft-tissue contrast compared to ultrasound and is particularly valuable when placental attachment to pelvic organs is suspected. However, its availability remains severely limited in sub-Saharan Africa due to cost and infrastructure constraints. In such settings, Aliyu et al. propose an alternative: transvaginal ultrasound with a Foley catheter balloon inflated in the bladder to distend the urinary bladder and thereby improve visualization of the uterine wall and gestational sac location [1][14].

In our first case, the diagnosis was not suspected antenatally due to the absence of any obstetric ultrasound. The diagnosis was made intraoperatively following presentation with massive hemoperitoneum. In the second case, despite an initial ultrasound raising suspicion, definitive localization was not achieved. An MRI would have been ideal to confirm the extrauterine implantation on the left broad ligament and ovary but was not feasible due to financial constraints.

In high-resource settings, abdominal pregnancy is typically diagnosed in the first trimester, enabling early intervention [5]-[7]. When diagnosed later, termination is generally recommended after multidisciplinary consultation and informed consent. Therapeutic options vary widely and include medical management with methotrexate (particularly in early cases, guided by the Fernández score), laparoscopic intervention for pregnancies <20 weeks’ gestation [4], or laparotomy, the standard approach in resource-limited environments where diagnosis is often delayed. Prenatal care coverage remains low in sub-Saharan Africa, with midwives being the primary providers. Some midwives believe that a pregnancy should only be investigated after three months of amenorrhea. Furthermore, limited access to quality ultrasound restricts prenatal diagnosis to the first trimester of pregnancy. The lack of early and systematic screening in these specific cases explains the late diagnosis as well as the poor outcomes.

Laparotomy should ideally be performed by a multidisciplinary team including vascular surgeons, urologists, and gynecologist obstetrician to manage potential complications such as massive hemorrhage or organ injury [7][15]. The most common sites of implantation are the Douglas pouch, followed by the mesosalpinx and omentum [16].

While there is consensus on the necessity of fetal extraction, controversy persists regarding placental management. The primary concern is uncontrolled hemorrhage if the placenta is adherent to vital organs or major vessels. Consequently, attempts at complete placental removal are strictly contraindicated in such cases [17][18]. The use of methotrexate for residual placental tissue has largely fallen out of favor due to unpredictable efficacy and delayed complications.

Some authors advocate for the simultaneous removal of both fetus and placenta. However, Aliyu [1] reported that 2 out of 6 patients in his series developed postoperative intestinal obstruction following complete placental extraction. In cases of catastrophic hemorrhage uncontrolled by conventional methods, hemostatic agents such as Floseal® a combination of human thrombin, gelatin, collagen, and cellulose matrix may be employed to promote local coagulation [19]. Yet, this agent is rarely available in our setting.

Therefore, many experts recommend leaving the placenta in situ after proximal ligation of the umbilical cord, particularly when placental implantation involves critical structures [4][6]. This conservative approach minimizes blood loss, reduces the risk of organ damage, and is especially advantageous in contexts with chronic shortages of blood products. In our first case, we adopted this strategy: the umbilical cord was ligated proximally, and the placenta was left in place. The patient experienced no postoperative bowel obstruction, and no methotrexate was administered. Instead, we implemented rigorous clinical and biochemical follow-up, monitoring for return of bowel motility and absence of obstructive symptoms.

In 2018, Marcelin et al. reported a case of advanced abdominal pregnancy managed with preoperative transcatheter placental embolization following fetal extraction via laparotomy. Four weeks later, the devascularized placenta was surgically resected with minimal blood loss and no organ injury [20][21]. This strategy represents a promising middle ground but requires advanced interventional radiology capabilities rarely accessible in our setting.

Postoperative monitoring typically involves serial ultrasound to assess placental volume regression and quantification of serial β-hCG levels. A progressive decline in β-hCG confirms placental resorption and is the most reliable biochemical marker of successful conservative management. In our first observation, the patient was lost to follow-up despite the need for close monitoring. This situation demonstrates the difficulty, under our conditions, of continuing monitoring when the clinical condition is progressing well. Ultimately, placental extraction depends on its insertion over vital organs or major blood vessels. Medical treatment with methotrexate can be initiated according to the Fernandez score, but not for advanced abdominal pregnancies. Traumatic placental extraction can lead to severe hemorrhage, organ damage, or fistula formation. In the second observation, placental extraction was successful. However, cautiously leaving the placenta in situ after proximal ligation of the umbilical cord suggests close monitoring.

The fetal prognosis in term abdominal pregnancy remains grim, with perinatal mortality ranging from 75% to 95% [22][23]. This high mortality stems from placental insufficiency due to ectopic implantation: the placenta develops in a non-vascularized, non-physiologic environment, leading to premature aging, fetal hypotrophy, malformations (cleft lip, clubfoot), oligoamnios, and intrauterine fetal demise all of which were observed in both our cases. As fetal demands increase during the third trimester, the inadequate perfusion provided by an ectopic placenta becomes incompatible with survival [24].

Maternal mortality in abdominal pregnancy is substantially higher than in other forms of ectopic pregnancy [1][9][10]. In our cases, complications such as severe anemia and postoperative wound infection prolonged hospitalization to 30 days in one patient—far exceeding the average of 10 days reported by Guèye et al. [5].

Abdominal pregnancy is rare. The maternal and fetal prognosis remains poor, particularly due to placental insufficiency and the risk of hemoperitoneum. This underscores the importance of early diagnosis of the pregnancy’s location through subsidized transvaginal ultrasound. Universal access to quality prenatal care is crucial. Indeed, any delay in the diagnosis and treatment of abdominal pregnancies can lead to an unfavorable maternal and fetal prognosis.