Challenging Diagnosis of Late Abdominal Pregnancy: A Case Study of Misdiagnosis and Fetal Death in the Third Trimester

Introduction

The incidence rate of extrauterine pregnancy is approximately 1 to 2% of the general population [1]. The most common ectopic pregnancy is a tubal pregnancy, while pregnancies with implantation outside the fallopian tube account for less than 10% of all extrauterine pregnancies [1,2]. Abdominal pregnancy is a form of extrauterine pregnancy in which implantation of the pregnancy takes place in the peritoneal cavity. Abdominal pregnancy is very rare and its incidence rate is difficult to estimate; some previous studies reported an incidence rate of 1% of all extrauterine pregnancies, or 1 per 10 000 to 30 000 pregnancies in general [3].

Risk factors for abdominal pregnancy are similar to those for all other forms of extrauterine pregnancies, including use of assisted reproductive technologies, previous abdominal operations or infections, intrauterine devices, contraceptive pills, smoking, and endometriosis [4–6].

The diagnosis of late abdominal pregnancy is challenging and usually based on complications, such as abdominal pain and hemorrhage [7].

Ultrasound examination in the first trimester is crucial in the case of ectopic pregnancy, as the likelihood of missing the diagnosis increases significantly in the second and third trimester [8]. Symptoms are highly variable, and are related to the implantation site and fetal age [9]. The general condition of the patient and the fetus form the basis of decision-making in the management of late abdominal pregnancy [10].

Late abdominal pregnancies generally have a bad outcome and are usually associated with serious fetal and maternal morbidity. The fetal mortality rate has been reported as between 45 and 90%. Maternal mortality has been recorded as 0.5 to 18% of all cases [11,12].

Due to the small number of reported cases and lack of sufficient data, there are still no evidence-based treatment guidelines or management strategies for patients with late abdominal pregnancy [13]. The present report presents the case of a 34-year-old-woman presenting as an emergency with an abdominal pregnancy and non-viable fetus. The aim of this case report is to demonstrate the necessity of considering, and if necessary, excluding abdominal pregnancy in similar conditions.

Case Report

A 34-year-old primigravida woman was admitted to the delivery room 2 months after the diagnosis of intrauterine fetal death at 33 weeks of gestation and undiagnosed extrauterine pregnancy with progressively deteriorating general condition. The patient’s initial presentation to our hospital occurred as an emergency with severe abdominal pain and displaying a severely cachectic and malnourished condition. She presented with a blood pressure of 94/63 mmHg, heart rate of 110 bpm, and body temperature of 36.1°C, likely due to onset of sepsis.

The patient had no previous medical record in our hospital. She had experienced no abnormal symptoms, such as vaginal bleeding or abdominal pain, during the first and second trimester and had had only one antenatal care visit during her pregnancy at 25 weeks. During this single visit, a vital fetus with severe intrauterine growth restriction was seen, and the patient was referred to a perinatal center for further investigation and follow-up. Due to severe social anxiety, she refused to be referred to the hospital and rejected any further investigations. During her next routine checkup by her midwife at 33 weeks, no fetal heartbeat could be detected. The patient was referred to the hospital with a suspected intrauterine fetal death. She decided to wait and refused further medical procedures.

Upon presentation at our hospital, abdominal palpation, as well as vaginal examination, was performed and showed no abnormal findings or evidence of suspicious extrauterine pregnancy, with a closed and unripe posterior cervix. An abdominal ultrasound examination was carried out and confirmed the diagnosis of intrauterine fetal death with a severe fetal maceration (in breech presentation) and anhydramnion. A sonographic assessment of the fetus’s gestational age was not possible due to the severe maceration. The laboratory investigations showed elevated infection parameters (leukocytes 17.5 Gpt/L, CRP 279 mg/L) and a severe thrombocytosis of 862 Gpt/L. Intravenous antibiotic therapy was immediately initiated due to a suspected severe infection with sepsis, most probably resulting from the maceration of the fetus and placenta. Initially ampicillin/sulbactam, and later meropenem and piperacillin/tazobactam, were administrated.

The decision to induce labor instead of immediate cesarean section was made at the request of the patient. She received 2 doses of misoprostol 50 µg p.o. at an interval of 6 hours.

Due to mild deterioration of the patient’s general condition and unsuccessful induction of labor, a decision to interrupt the induction of labor and to perform an urgent cesarean section was taken.

The patient was taken to the operating room and given general anesthesia. A Pfannenstiel incision was made, and the fascia was transversely incised and dissected. Upon opening the abdominal cavity, no regular anatomy could be identified; the abdomen was characterized by a thickened parietal peritoneum with suspected peritonitis. After incision of the parietal peritoneum, a viscous brown fluid with a strong foul odor was drained. This cavity was initially suspected to be the uterine cavity. Solid parts could be seen and later identified as fetal parts (Figure 1). The placenta was adherent to the serosa of the anterior uterine wall as well as the broad ligament (Figure 2). This was completely removed without a significant blood loss. After complete drainage and removal of the severely macerated fetus (Figure 3), the cavity was inspected carefully but no cervical canal could be identified. To confirm the diagnosis of abdominal pregnancy, a diagnostic hysteroscopy was performed and showed a regular, empty uterus with hyperplastic endometrium (Figure 4). Inspection of the uterus and adnexa was not possible. A further exploration of the abdomen was not performed due to multiple adhesions and disturbed anatomy. The fascia and skin were closed with a running Vicryl suture after insertion of an intraabdominal drain. Estimated blood loss was 800 mL. The patient did not consent to a pathological examination of the fetus. The pathological examination of the placenta revealed inflamed necrotic tissue and decidua.

Postoperatively, the patient was transferred to the intensive care unit in a stable condition. She recovered quickly and was able to be transferred back to the gynecological ward after 24 hours. Microbiological examination of the samples taken from the abdominal cavity identified Escherichia coli, Streptococcus anginosus, Clostridium ramosum, Olsenella uli, Parvimonas micra, and Bacteroides thetaiotaomicron. Prior to discharge, an abdominal ultrasound was performed and showed no further pathological findings. Upon contact for consent for this publication, she reported prolonged healing of the surgical incision but otherwise good health and satisfactory recovery.

Discussion

The presented case, along with other previously reported cases of late abdominal pregnancies [7,8,14] demonstrates the necessity to consider and exclude abdominal pregnancy under similar clinical conditions. The undiagnosed ectopic pregnancy in our case at the initial presentation led to delayed and inappropriate management, beginning with induction of labor instead of immediate laparotomy. Missed diagnosis in such cases could make management more difficult and cause serious complications [8].

According to the pathophysiological development, abdominal pregnancies are classified into primary abdominal pregnancy and secondary abdominal pregnancy [3,15]. Another classification depends on the time of diagnosis, which classifies abdominal pregnancy into early abdominal pregnancy and late abdominal pregnancy [3]. Heterotopic abdominal and intrauterine pregnancies have also been described in previous studies [13].

Symptoms of advanced abdominal pregnancy are usually non-specific, including abdominal pain, vaginal bleeding, nausea or vomiting, bowel obstruction, or in some cases pronounced painful fetal movements [9]. Epigastric pain with anemia was descried by Wong et al in omental pregnancy [16]. Advanced abdominal pregnancy without any abnormal symptoms during the pregnancy has also been reported [8]. In our case, the patient had no abnormal symptoms during the first and second trimester but presented in our hospital 2 months after the diagnosis of intrauterine fetal death at 33 weeks of gestation with a poor general condition, likely due to severe pain and sepsis.

The 34-year-old primigravida had had only one antenatal care visit at 25 weeks. During this visit, a vital fetus was seen. During her next routine checkup by her midwife at 33 weeks, no fetal heartbeat could be detected. This indicates that fetal death occurred within the gestational age range of 25 to 33 weeks. The diagnosis of late abdominal pregnancy was missed. The diagnosis of abdominal pregnancy in the second and third trimester is difficult and can be missed up to 50% of the time, despite regular antenatal care and imaging [11,17]. Chen et al published a case report of abdominal pregnancy and review of 17 other cases, and reported that only 5 out of 17 cases were diagnosed before surgery [9]. Similar results were published by Atrash et al, reporting that only 11% of 5221 cases of abdominal pregnancies were diagnosed pre-operatively [18].

In this reported case, abdominal pregnancy was not considered as a differential diagnosis at the time of presentation. Ultrasound findings showed a typical picture of intrauterine fetal death, and failed to detect the missing uterine wall around the pregnancy or the empty uterus in the pelvis. The lack of regular antenatal care made the diagnosis more difficult in this case. Abdominal and vaginal sonographic assessment during pregnancy, especially in the first trimester, can be very helpful in showing an empty uterus, abnormal localization of the placenta, absence of uterine wall around the fetus, and very common fetal growth restriction [8,15].

Clinical signs of extrauterine pregnancy can be highly variable, according to the location of the pregnancy. They can include abdominal tenderness with or without signs of peritonitis, and rarely, hemorrhagic shock in the case of abdominal bleeding. MRI may be a useful diagnostic procedure, especially preoperatively as a part of the operative planning, facilitating accurate localization of the placenta [19]. It is very important to consider extra-uterine pregnancy as a differential diagnosis to be able to identify these abnormal signs and diagnose abdominal pregnancy.

The outcome and prognosis of abdominal pregnancy can range from asymptomatic pregnancy with a live birth to fetal mortality with serious maternal complications. Nassali et al reported a case of an abdominal pregnancy with a normal course and a live birth at 41 weeks of gestation [8]. Dabiri et al reported another case of abdominal pregnancy with a healthy newborn at 33 weeks [7].

Management of advanced abdominal pregnancy depends on the general condition of the patient and the fetus as well as the site of placental implantation. Patients in stable general condition with a live baby should be informed about possible outcomes and complications, and encouraged to make their own choice about termination of pregnancy or expectant management. Delivery, whenever possible, should be planned after 32 weeks of gestation, and starting from this point of time, a weekly MRI is recommended to avoid major complications [20].

Patients in stable general condition with fetal death should be operated in a tertiary care center with a multidisciplinary team that is experienced in the management of severe hemorrhage [3]. A vertical laparotomy must be performed to maximize intraoperative abdominal exposure. Management of the placenta is still unclear; some surgeons prefer immediate removal of the placenta, while others prefer leaving the placenta in situ to minimize blood loss with or without postoperative methotrexate therapy [13,21].

Patients in an unstable hemodynamic or septic condition require an urgent laparotomy and termination of the pregnancy. In our case, the decision to terminate the pregnancy operatively was made due to the deterioration of the patient’s general condition, along with the known intrauterine fetal death. The abdominal pregnancy was an incidental diagnosis, and the placenta did not show any signs of placental implantation disorders in terms of tissue penetration, and could be removed easily without significant blood loss. In such undiagnosed cases, major complications can occur, and their management is usually challenging. In many previously reported cases of abdominal pregnancy, a supracervical or total hysterectomy was recommended because of severe bleeding [7,22]. The most serious maternal complications of late abdominal pregnancy reported are hemorrhage and sepsis. Fetal complications, if the fetus survives, include fetal growth retardation due to poor placental blood supply and fetal deformation due to oligo- or anhydramnion and fetal compression [10].

Conclusions

The diagnosis of late abdominal pregnancy can be missed despite clinical and sonographic examination. Extrauterine pregnancy should be considered in similar cases to the one presently reported, with suspected findings. Multidisciplinary management and proper preoperative planning must be done in well-specialized tertiary centers.