Advanced abdominal pregnancy secondary to tubal pregnancy: a rare case report and literature review

Abstract

Background

A pregnant woman was found to have a left tubal pregnancy on transabdominal ultrasound (9 weeks 5 days by CRL). However, she refused any treatment and left the hospital. Nearly 3 months later, this woman was admitted to the emergency room due to severe abdominal pain. The emergent ultrasound scan revealed an abdominal ectopic pregnancy at 22 weeks’ gestation. The placenta covered the left abdominal wall and was implanted into the omentum, intestinal wall, and bladder wall. Magnetic resonance imaging (MRI) confirmed the diagnosis. The location and relationship of the placenta to its adjacent organs were delineated on the abdominal surface based on ultrasound findings. On the third day of admission, a laparotomy was performed and the fetus was delivered (Apgar score 3). The placenta was detached and removed without any complications.

Case presentation

Advanced abdominal pregnancy (AAP) is rare and severe ectopic pregnancy, defined as intraperitoneal pregnancy excluding tubal, ovarian, or intraligamentous pregnancy, progressing beyond 20 weeks of gestation. Monitoring the whole development process from a tubal pregnancy to AAP, with a viable fetus, is much rarer. Therefore, we present this case, review the literature on AAP, and summarize its characteristics as well as management.

Conclusions

Ultrasound and MRI are vital for improving outcomes in AAP, which remains a potentially life-threatening condition. Ultrasound and MRI should be used to confirm the location of the gestational sac in relation to the endometrial cavity and the placenta in relation to abdominal organs. Accurate diagnosis and appropriate multidisciplinary team (MDT) management can lead to favorable outcomes.

Background

Abdominal pregnancy is a rare and serious form of ectopic pregnancy, defined as an intraperitoneal pregnancy excluding tubal, ovarian, or intraligamentary implantation, first reported in 1708 as an autopsy finding. Advanced abdominal pregnancy (AAP) is generally defined as a pregnancy that progresses beyond 20 weeks of gestation with a viable, growing, and developing fetus [1].

The incidence of abdominal pregnancy ranges from 1 in 10,000 to 1 in 30,000 births according to different references [2]. Ectopic pregnancies have a high risk of mortality accounting for 6–13% of all pregnancy-related deaths [3]. The non-tubal ectopic pregnancies have a 7 to 8 times higher risk of maternal mortality compared to tubal pregnancies [4]. According to the original implantation site, abdominal pregnancy can be classified into two types: primary and secondary. Secondary abdominal pregnancy is secondary to tubal embryo implantation or uterine scar rupture, mostly accompanied by hemoperitoneum.

Here, we report a rare case of an AAP secondary to a left tubal pregnancy diagnosed by ultrasound at 9 weeks of gestation, confirmed with both ultrasound and magnetic resonance imaging (MRI) at 22 weeks. The ultrasound played a main role in establishing a definitive diagnosis, monitoring the progression of pregnancy, and guiding surgical intervention.

This case study was approved by the Medical Ethics Committee of the Huazhong University of Science and Technology Graduate School and Faculty, and written informed consent was obtained from all participants.

Case presentation

A 38-year-old pregnant woman with gestational hypertension, hyperthyroidism, a heart rate of 150 bpm, and an upper respiratory tract infection (URTI) was found to have an abdominal pregnancy due to sudden abdominal pain for one day. The patient, who had 30 days of amenorrhea, self-tested positive for urine hCG. Ultrasonography at approximately 40 days’ gestation demonstrated a left adnexal hypoechoic mass suggestive of ectopic pregnancy, with an embryonic pole and primitive cardiac activity visualized. The patient was asymptomatic (no vaginal bleeding or abdominal pain) and declined further management. At 9 weeks' gestation, the ultrasound confirmed a viable singleton left tubal ectopic pregnancy. The physician recommended hospitalization; however, the patient declined. The patient had two subsequent presentations for febrile cough. Laboratory testing confirmed an infection, after which the patient declined therapeutic intervention, with eventual spontaneous resolution of symptoms.

Nearly three months later, this woman was admitted to the emergency room with severe abdominal pain that had lasted for several hours. The emergent ultrasound scan revealed an abdominal ectopic pregnancy at 22 weeks’ gestation with a head circumference of 208 mm. The uterus was found in the right flank, adjacent to the bladder, with thickened endometrium and an empty cavity. The placenta covered the left abdominal wall and measured up to 59.5 mm in maximum thickness. Twisted communicating vessels were observed between the placenta and the omentum and intestinal wall, as well as between the placenta and the bladder wall (Fig. 1). The ultrasound confirmed the diagnosis of abdominal pregnancy. Blood pressure was documented at 138/121 mmHg, with no cardiorespiratory symptoms or vaginal bleeding. Given the patient’s history of salpingectomy for ectopic pregnancy three years prior and two documented episodes of febrile cough during the early and mid-trimester, secondary implantation may have been facilitated by postoperative peritoneal adhesions in conjunction with transient surges of intra-abdominal pressure induced by coughing.

Fig. 1.

Ultrasound revealed a left tubal pregnancy at 12 weeks and an AAP at 22 weeks. A The fetus is 9 weeks and 5 days measured by CRL. B CDFI: Color blood flow signal. C Normal uterine morphology, thickened endometrium, and empty uterus. D,E,F The twisted communicating branches were found between the placenta and the intestinal wall, as well as between the placenta and the bladder wall. G The spectrum of the umbilical artery can be detected in the twisted communicating branches. H The fetal were found in abdomen, outside the large and empty uterus. I The fetal heart was examined by M-mode echocardiography P, placenta; BL, bladder; UA, uterine artery; U, uterus; F, fetus; IN, intestine

MRI scan confirmed that the fetus and placenta were seen in the left adnexal area. The placenta was mainly located in the left omentum and anterior abdominal wall. The uterus was enlarged and compressed toward the right (Fig. 2). The blood supply of the placenta was derived from the arteries of the omentum and intestinal wall, as confirmed by both ultrasound and MRI imaging.We conducted a thorough preoperative evaluation and prepared for potential intraoperative situations, including significant intraoperative bleeding, maternal DIC, and fetal survival, and other possible complications.

Fig. 2.

MRI scan confirmed an ectopic pregnancy in the left side of the abdomen. A The placenta was mainly located in the left anterior wall. B The fetus and placenta were found in the left adnexal area. And the uterus, with thickened endometrium, was enlarged and compressed to the right. Am, amniotic fluid; P, placenta; H, head; U, uterus; B, bladder

On the 3rd day of admission, the laparotomy was performed, and the fetus was delivered. The placenta was split into three fragments, with noted thrombus and infarction, as well as trophoblastic invasion of the omentum and intestinal wall (Fig. 3). Blood loss was estimated at 2000 ml. she received autologous blood transfusion and 4 units of PRBC during and after the surgery. The fetus was born in poor condition (Apgar score 3) and unfortunately died in 30 min.

Fig. 3.

The laparotomy was performed and the fetus was delivered. A The location and relationship of the placenta to its adjacent organs were delineated on the abdominal surface according to ultrasound. B The twisted communicating branches were ligated, between the placenta and the intestinal wall, as well as between the placenta and the bladder wall. C After the delivery of the fetus, the placenta was found to have split into three fragments, with evidence of thrombi and infarction, as well as trophoblastic invasion of the omentum and intestinal wall

The histopathological examination proved the abnormal adipose tissue attached to the chorionic plate, associated with villous cell necrosis and infarcted lesions (Fig. 4).

Fig. 4.

The histopathological examination of this AAP (× 200). A The abnormal adipose tissue is attached to the chorionic plate. B The villi cells necrosis and infarcted lesion of placenta

The patient received 3 days of intensive care postoperatively before transfer to the general obstetric ward. On postoperative day 3, she requested discharge. She was instructed to continue wound management at local hospitals until complete healing and to seek immediate re-evaluation for symptoms including abdominal pain, rectal tenesmus, or abnormal vaginal bleeding. Serial serum β-hCG monitoring at 1 month postoperatively showed no abnormal fluctuations. Three-month follow-up pelvic ultrasound demonstrated progressively decreasing fluid volume with residual patchy hyperechoic areas and fine septations.

Discussion

Abdominal pregnancy is a kind of serosal pregnancy in ectopic pregnancy. According to the implantation site, abdominal pregnancy can be divided into intraperitoneal implantation and retroperitoneal implantation. Intraperitoneal implantation sites include all locations on the uterine serosa, the uterine ligaments, the liver, spleen, and bowel, including the mesentery and the peritoneum of the pelvic wall, the diaphragm and the inguinal canal. Retroperitoneal implantation sites include the large arteries, in the area of the pancreas and the kidneys, in rectovaginal and paravesical spaces and in the obturator foramen [3].

According to the original implantation site, abdominal pregnancy can be divided into two types: primary and secondary. Primary abdominal pregnancy is rare and the cause of its occurrence is unclear. The peritoneal epithelium may transform into the paramesonephric duct epithelium, especially in the presence of ectopic endometrium in the peritoneal cavity or pelvic cavity, which can lead to the implantation of the zygote and the development of primary peritoneal pregnancy.

There are several theories about the pathophysiology of secondary abdominal pregnancy. First, vascular and lymphatic metastasis has been proposed [5–7]. In the studies of Persson et al. [8] and Liang C et al. [9], the lymphatic tissues were found together with the ectopic mass. In addition, the classic signs of the inflammatory response along the gonadal vessels, believed to be a result of obstructed lymphatics due to embryo migration, were observed using CT reconstruction techniques. Second, abdominal metastasis may occur due to a fistulous tract or uterine perforation [10]. Iwama et al. [11] observed an adhesion at one of the tubal ends during salpingectomy and speculated about a fistula. Arora et al. [12] supposed that ectopic pregnancy occurring immediately after hysterectomy was likely due to a fertilization in the tubes during hysterectomy. It was also considered a consequence of a fistula between the vagina and prolapsed fallopian tube or peritoneum [13]. Third, direct implantation. After other ectopic pregnancies, such as the abortion of ovarian pregnancy or rupture of tubal pregnancy/uterine horn pregnancy [14], the active fetal villi were implanted directly on the peritoneal surface, or extruded to the posterior peritoneum by intestinal peristalsis [15, 16]. Wang et al. [17] presented a case involving the spontaneous rupture of a tubal pregnancy at 15 weeks and 3 days of gestation diagnosed during surgery. Moreover, retrograde menstrual flow could reverse the course of a fertilized ovum in the tubal course. Fourth, assisted reproduction. The zygote may enter the abdomen through uterine perforation caused by egg retrieval.

The clinical symptoms of abdominal pregnancy without complications are nonspecific [4]. Typical clinical symptoms of a ruptured ectopic pregnancy include progressive pain in the lower abdomen, sometimes with intraabdominal or vaginal bleeding, even hemorrhagic shock, dizziness, faintness, and nausea. The most common signs are pronounced peritonism, malpresentation, and failure of induction of labor due to non-responsiveness of the uterus to oxytocin, fetal growth restriction, and low amniotic fluid volume. However, abdominal pregnancy is often misdiagnosed until late pregnancy, evolving into abortion, embolism, or rarely live birth by cesarean section as in this case. With a positive pregnancy test, typical clinical presentations coupled with ultrasonography and MRI can help confirm the diagnosis.

Ultrasound is the preferred diagnostic modality for abdominal pregnancy. The typical sonographic features of AAP include fetal localization within the abdominal cavity, absence of the uterine myometrial layer between the bladder wall and the fetus, unilateral displacement of an enlarged uterus, and an empty uterine cavity. An abnormal fetal position and oligohydramnios are frequently observed. Abdominal pregnancies are commonly associated with placental implantation, and tortuous vascular connections may be identified between the placenta and adjacent organs or tissues, such as the intestinal wall, omentum, and so on. It is crucial to accurately determine the precise site of placental implantation through ultrasound imaging prior to management.

MRI contributes to making a definitive diagnosis of abdominal pregnancy as well as to determining the location and relationship of the placenta to adjacent organs [1, 18]. Furthermore, other diagnostic methods include laparoscopic exploration, laparotomy, arteriography, biopsy, and so on.

Moreover, there are some pitfalls in the diagnosis of AAP, such as anterior uterine leiomyoma, retroflexed uterus, false-negative diagnosis of intrauterine pregnancy, and false-positive diagnosis with a bicornuate uterus [13].

Because of the rapid progression of hemorrhagic shock due to heavy bleeding, AAP is a serious obstetric emergency. The management includes surgical therapy (laparotomy and laparoscopy), medical injection therapy (intramuscular or intralesional methotrexate and/or intracardiac KCl), and a combination of medical and surgical management [13].

We conducted a literature review of 36 articles on AAP published between 2016 and 2025, using electronic searches in MEDLINE, EMBASE, PubMed, and Web of Science. This review was limited to human studies published in English and included case reports, case series, and systematic reviews. Descriptive statistics are provided to illustrate the clinical characteristics, diagnostic methods, and management strategies of abdominal pregnancy (Table 1).

Table 1.

The reported cases and available data

Authors	The number of case	GA at admission (weeks)	GA at delivery (weeks)	average period (days)	Symptoms	Risk factors	Amniotic fluid	Diagnostic Tool	Misdiagnosis	Placenta			AAP management	blood transfusion	medicine	Maternal outcome	fetal outcome
										Implantation site	Feeding arteries	management
Yacouba MC et al. (2025) [19]	1	32	32	0	abdominal pain	/	/	US	no	right ovary and greater ligament	/	removed	surgery	no	/	discharged	neonatal death
Pradyta E et al.(2025) [20]	1	31	31	0	abdominal pain	history of laparotomy	/	/	yes	omentum	/	left in-situ	surgery	no	/	discharged	stillbirths
Claudio RE et al. (2025) [21]	1	30	30	0	abdominal pain	ectopic pregnancies and left salpingectomy	/	US&CT	no	abdominal wall	/	removed	surgery	yes	/	discharged	stillbirths
El Hajjar C et al. (2024) [22]	1	26	26	0	severe abdominal pain, fever and chills	curettage procedure	/	US	yes	posterior uterine wall (Douglas pouch)	/	removed	surgery	no	broad-spectrum antibiotics	discharged	stillbirths
Gupta K. et al.(2024) [23]	1	34	34	0	abdominal pain	/	no measurable pools	US/MRI	no	fundus of uterus,mesentry	enlarged mesenteric vessels and left external iliac artery	removed	surgery	no		discharged	neonatal death
Alwafai Z. et al.(2024) [24]	1	33	33	0	severe abdominal pain	/	/	US	yes	serosa of anterior uterine wall as well as broad ligament	external iliac artery	removed	surgery	yes	antibiotics	discharged	stillbirths
Joshi RR. et al.(2024) [25]	1	36	36	0	no	tubal ligation and recanalization	/	US	no	right adnexa, ovary, and fallopian tube	/	removed	surgery	yes	/	discharged	stillbirths
Joshi RR. et al. (2024) [25]	1	24	24	0	abdominal pain, vaginal bleeding	cesarean section	/	US	yes	right iliac fossa	/	removed	surgery	yes	/	discharged	stillbirths
Joshi RR. et al.(2024) [25]	1	20	20	0	severe anemia and septic shock	/	/	US	yes	back of uterus, bowel, and omentum	/	removed	surgery	yes	/	death	stillbirths
Magezi J. et al. (2024) [26]	1	38	38	0	no	/	oligohydramnios	US	no	omentum	ovarian, mesenteric, and uterine vessels	removed	surgery	yes	/	discharged	live
Ramphal S. et al. (2023) [27]	46	28	32	27 (12–57)	abdominal pain (46/46, severe 4/46), vaginal bleeding (8/46)	inflammatory disease (4/46), laparotomy for a previous ectopic pregnancy (1/46), HIV infection (30/46)	normal (17/46), oligohydramnios(12/46), no measurable pools (17/46), absent (0/46)	US (46/46)	no (46/46)	Douglas pouch, the posterior wall of the uterus, and both posterior broad ligaments and the rectum, and so on	/	left in-situ (2/46), removed (44/46)	expectation (46/46)	blood transfusion (40/46)	Steroid mature at 30 weeks of gestation (46/46)	discharged (46/46)	stillbirths (2/46), neonatal death (11/46), live (33/46)
Harries S. et al.(2023)[28]	17	31	31	0	/	smoking (2/17), abdominal surgery (5/17) (4 caesarean sections and 1 ectopic pregnancy)	/	US (16/17),US & MRI (1/17)	no (17/17)	4 omentum, 3 sigmoid colon, 3 rectum, 2 posterior uterine surface, 2 posterior cul-de-sac, 1 transverse colon, 1 small bowel, 1 pelvic side wall, 1 left ureter, 1 bowel, 1 appendix	/	removed (15/17), left in-situ partially (2/17)	surgery (17/17)	blood transfusion (14/17)	Steroid mature (5/17)	Death (2/17), discharged (15/17)	stillbirths (6/17), neonatal death (2/17), live (9/17)
Legesse, T. K. et al. (2023) [29]	1	37	37	0	abdominal pain	/	oligohydramnios	US	no	broad ligament and right adnexa, right ovary	the tubal branch of the uterine artery	removed	surgery	yes	/	discharged	live
Iovenitti P. et al. (2023) [30]	1	39	39	0	no	/	/	US	no	epiploon, left ovary and salpinx	/	removed	surgery	yes	/	discharged	neonatal death
Utalo T. et al. (2022) [31]	1	38	38	0	abdominal pain	/	oligohydramnios	US	yes	left broad ligament, left ovary, small bowel mesentery, and posterior wall of uterus	/	removed	surgery	no	/	discharged	neonatal death
Tegene D. et al. (2022) [32]	1	36	36	0	vaginal bleeding	/	/	US	no	cecum and mesentery of gastrointestinal tract	/	removed	surgery	no	/	discharged	stillbirths
Chan A. et al. (2022) [33]	1	23	23	0	abdominal pain	/	/	US&CE-MDCT	no	uterine fundus and adjacent bowel	right uterine artery	left in-situ	surgery (bilateral uterine artery coil embolization before laparotomy)	no	methotrexate	discharged	stillbirths
Momtahan M. et al. (2021) [34]	1	36	36	0	no	/	/	US	yes	right adnexa, cecum and pelvic cavity right side	/	removed	surgery	yes	/	discharged	live
Soewondo W. et al. (2021) [18]	1	30	30	0	no	/	/	US&MRI	no	urinary veins, uterus, omentum, and descending colon	/	left in-situ	surgery	NO	/	discharged	live
Muroni M. et al. (2021) [35]	1	37	37	0	abdominal pain	left tubal pregnancy	oligohydramnios	US	no	Douglas pouch	unidentifiable	removed	surgery	yes	/	discharged	Infant death
Hofmeyr GJ. et al. (2021) [36]	1	37	37	0	abdominal pain	/	oligohydramnios	US	yes	entire pelvis	posterior wall of the pelvis	removed	surgery (Foley catheter tourniquet hemostasis)	yes	/	discharged	live
Paluku JL. et al.(2020) [2]	1	33	33	0	severe abdominal pain	/	oligohydramnios	US	yes (acute peritonitis)	greater omentum and on small bowel mesentery	/	left in-situ	surgery	yes	antibiotics, analgesic	discharged	live
Chun PC. et al. (2019) [37]	1	38	38	0	abdominal pain	right ectopic pregnancy	/	TUS	YES	right adnexa, terminal ileum, proximal caecum, and appendix	/	left in-situ partially	surgery	yes	tranexamic acid	discharged	live
Odelola OI. et al. (2019) [38]	1	9	33	171	severe abdominal pain, vaginal bleeding	/	normal	TUS	NO	a broad stalk to left infundibulopelvic ligament, broad ligament, and also left tube		removed	expectation	yes		discharged	live
Shurie S. et al. (2018) [39]	1	35	35	0	vaginal bleeding	/	/	US	no	anterior abdominal wall and mesentery posteriorly	/	removed	surgery	no	misoprostol	discharged	stillbirths
Mforteh AA. et al. (2018) [40]	1	39	39	0	reduced fetal movements	/	/	US	yes	ascending colon and mesocolon	/	left in-situ	surgery	no	misoprostol, ampicillin, gentamycin, metronidazole, methotrexate	discharged	stillbirths
Rohilla M. et al. (2018) [1]	1	40	40	0	no	/	/	US	yes	fallopian tube wall	/	left in-situ partially	surgery	yes	/	discharged	live
Marcelin C. et al. (2018) [41]	1	27	28	0	no	/	oligohydramnios	US&MRI&CT	no	upper side of uterus	the left uterine and sigmoid arteries from the inferior mesenteric artery	left in-situ with embolization, and removed 45 days later	surgery	no	/	discharged	live
Maciel N. et al. (2017) [42]	1	37	37	0	no	/	oligohydramnios	US	yes	left broad ligament and closely apposed to left infundibulopelvic ligament	/	removed	surgery	no	/	discharged	stillbirths
Hailu FG. et al. (2017) [4]	1	37	37	0	abdominal pain	sever preeclampsia	no measurable pools	US	YES	posterior aspect of uterus and right broad ligament	/	removed	surgery	yes	Ceftriaxone and metronidazol	discharged	live
Tolefac PN. et al. (2017) [43]	1	25	25	0	nonspecific abdominal distension	/	oligohydramnios	TUS, TVS	YES	fundus and posteriorly to large intestine	/	left in-situ	surgery	no	misoprostol	discharged	neonatal death
Oppenheimer A. et al. (2017) [44]	1	31	32	2	abdominal pain	dilatation and curettage abortion	oligohydramnios	TUS/MRI	NO	peritoneum and omentum	large branch from the anterior wall of the right iliac vessels	removed	surgery	No significant bleeding occurred	corticosteroid therapy	discharged	live
Abdelrahman S. et al. (2017) [44]	1	35	34	0	abdominal pain	/	/	US	YES	fundus and left cornual region of uterus, small bowel mesentery and left lateral abdominal wall	/	left in-situ partially	surgery	yes	antibiotic therapy	discharged	live
Udigwe GO. et al. (2016) [45]	1	27	34	49	abdominal pain, vomiting, constipation	/	/	US & Plain abdominal X-ray	no	gut	/	removed	expectation	yes	omeprazole, amoxicillin-clavulanic, metronidazole, analgesics due to acute intestinal obstruction secondary to AAP	discharged	live
Harirah HM. et al. (2016) [46]	1	28	29	6	no	infertility and left hydrosalpinx	oligohydramnios	MRI&US&Enhanced MRI	NO	majority of omentum and small bowel mesentery	/	left in-situ partially	surgery	yes	/	discharged	live
Harirah HM. et al. (2016) [46]	1	23	30	49	abdominal pain	genital chlamydia trachomatis infection	oligohydramnios	TUS, TVS&MRI	NO	anterior aspect of dome of uterus, rectosigmoid junction, sigmoid colon, and right ovary	/	left in-situ	expectation	no	betametha-sone, magnesiumsulfate	discharged	live
El-Agwany AS. et al. (2016) [47]	1	24	24	0	abdominal pain	hysterectomy specimen revealed thinning near the fundus	/	TUS	no	fundus of uterus	/	left in-situ partially	surgery	yes	/	discharged	neonatal death
Nassali MN. et al. (2016) [48]	1	41	41	0	no	HIV infection	/	TUS	yes	omentum, ileal mesentery and extending to pouch of Douglas	/	removed	surgery	yes	/	discharged	neonatal death
Aliyu I. et al. (2016) [49]	1	36	36	0	abdominal pain, vaginal bleeding	/	/	US	no	the omentum	/	removed	surgery	yes	ceftriaxone, metronidazole	discharged	live

CE-MDCT contrast-enhanced multidetector computed tomography, CT Computed Tomography, HIV human immunodeficiency virus, MRI Magnetic Resonance imaging, TUS Transabdominal ultrasound, US Ultrasound

AAP is often missed in early pregnancy or due to a lack of antenatal care. Currently, the management of abdominal pregnancy includes expectant management or surgical management. If ultrasound indicates normal fetal development and amniotic fluid [27], expectant management may be continued until 34 weeks of gestation or until the week when a newborn can survive. All cases (49/49) that underwent expectant management were selected for delivery at 30 weeks or later [27, 38, 45, 46]. However, surgical treatment is the most common approach, with laparotomy being the preferred option.

Among the 100 fetuses with AAP described in the 36 articles, only 17 cases (17.0%) were missed before surgery, indicating improved diagnostic accuracy over the past decade. A total of 49 cases (49.0%) received expectant management, of which 18 exhibited normal amniotic fluid volume (36.7%). Among these 49 cases, 2 maternal deaths (4.1%) occurred, with fetal outcomes including 2 stillbirths (4.2%), 11 neonatal deaths (22.4%), and 36 live births (73.5%). Fifty-one cases underwent surgical treatment, with 1 maternal death (2.0%). Fetal outcomes in this group included 18 stillbirths (35.3%), 10 neonatal deaths (19.6%), and live births 23 (45.1%). Overall, the maternal mortality rate associated with AAP is approximately 3.0%, based on data from 100 reported cases, whereas the fetal mortality rate reaches as high as 41.0%. However, because some cases of abdominal pregnancy with sudden onset and maternal death, which resulted in incomplete clinical data, have not been published, our data may underestimate the mortality rate.

Therefore, standardized prenatal examinations are essential. In cases where a pregnant woman declines medical intervention, healthcare providers should clearly communicate the potential risks associated with adverse perinatal outcomes and establish regular telephone follow-up protocols to support improved maternal health outcomes. Other factors may have contributed to the reduction in maternal and fetal mortality rates over time, such as advanced imaging modalities, increased awareness among pregnant women and obstetricians, improvements in surgical techniques and treatment strategies, greater availability of blood products and medications, and enhanced access to tertiary care centers.

The key to surgical management lies in placental management. Complete removal of the placenta is recommended if it is not implanted in vital organs and has minimal adhesion to surrounding tissues. If the feeding vessel is unclear or dissection may cause significant tissue damage, leaving the placenta in situ is recommended. The placenta was completely removed in 84 cases, including one case in which severe infection developed after uterine artery embolization, requiring its removal 45 days later. Among the 16 cases in which the placenta was left in situ, nine cases involved partial removal due to massive bleeding and the inability to achieve complete dissection.

The use of methotrexate at AAP is debatable, as it works best on rapidly dividing cells and is less likely to help in case of a mature placenta [30, 46]. Most studies recommend avoiding chemotherapy and allowing spontaneous resorption to prevent severe intra-abdominal infection caused by rapid placental necrosis from potent drugs. However, some scholars suggest that residual placenta after surgery may still require medical treatment, with low-dose systemic methotrexate administered postoperatively, accompanied by close monitoring of hCG levels and ultrasound. Reoperation to remove the placenta may be necessary after 2–3 months if indicated [4, 18, 40]. This approach is not recommended in cases of uterine or tubal rupture [50].

Preoperative embolization of placental feeding vessels can reduce perioperative bleeding and transfusion requirements [32], however, uterine artery embolization may lead to reduced postoperative menstrual flow and decreased pregnancy rates. Prophylactic abdominal aortic balloon occlusion may reduce intraoperative bleeding. In addition, severe postpartum hemorrhage may occur in AAP, so adequate intraoperative blood supply must be ensured for resuscitation [25]. Eighty-five cases (85.0%) required blood transfusion.

Postoperative management of abdominal pregnancy surgery is crucial. Due to the extensive surgical field and potential intestinal injury, the risk of postoperative infection is high. Antimicrobial agents targeting intestinal flora are recommended [2, 22, 44].

Conclusion

Abdominal pregnancy is a rare and serious form of ectopic pregnancy, especially when monitoring the whole development process from a tubal pregnancy to AAP with an alive fetus. The recognition of suspicious symptoms, the use of ultrasound and MRI, and appropriate surgical and/or drug treatment are indispensable for AAP management. In addition, ultrasound and MRI are necessary and reliable tools for preoperative localization and postoperative follow-up. Therefore, early diagnosis and ensuring an excellent prognosis are still our major challenges.

Abbreviations

AAP

Advanced abdominal pregnancy

CE-MDCT

Contrast-enhanced multidetector computed tomography

CT

Computed Tomography

HIV

Human immunodeficiency virus

MDT

Multidisciplinary team

MRI

Magnetic Resonance imaging

TUS

Transabdominal ultrasound

URTI

Upper respiratory tract infection

US

Ultrasound

Authors’ contributions

LC wrote the main manuscript text. HG operated on the patient. HC and MX designed the study. LH was involved in the ultrasound diagnosis, reviewed and edited the manuscript. JM conducted pathological sampling and sectioning of the specimens, and prepared Fig. 4. JL, JS, and YZ prepared Figs. 1, 2 and 3 and collected materials for the preparation of the publication. All authors read and approved final manuscript.

Funding

This study was supported by the National NaturalScience Foundation of China (grants 82202194, 82230066, and 82302230), and the Joint Fund Project for Innovation and Development of Natural Science Foundation of Hubei Province (grants 2025AFD874).

Data availability

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

This case study was approved by the Medical Ethics Committee of the Huazhong University of Science and Technology Graduate School and Faculty and the case provided with written informed consent.

Consent for publication

Written informed consent was obtained from the patient for publication. There are no identifying images or other personal or clinical details of the patient that compromise their anonymity in this manuscript.

Competing interests

The authors declare no competing interests.