Abdominal pregnancy

　　Primary abdominal pregnancy is very rare, and the cause of its occurrence is unknown. However, some scholars believe that peritoneal epithelium may transform into paramesonephric duct epithelium, especially when there is ectopic endometrium in the peritoneum or pelvis, which allows the fertilized egg to implant and develop into primary abdominal pregnancy.

　　Secondary abdominal pregnancy mostly occurs in the case of ruptured tubal pregnancy or after abortion, where the gestational material originates from the rupture site or fimbria, but part of it still adheres to the affected area. The villi of the implantation site survive and attach to the nearby peritoneum or organs, continuing to develop into abdominal pregnancy. A small number of cases occur after the rupture of ectopic pregnancy in the ovary. As for those who have had cesarean sections and become pregnant again, the cesarean section incision may rupture, with the fetus wandering outside to the abdominal cavity, or other causes of uterine incisions, such as uterine abdominal fistula, can also lead to rare abdominal pregnancy. Due to the different attachment site of the placenta in abdominal pregnancy from that in the normal uterus, the blood supply is very poor, resulting in poor fetal development. Only 5% to 10% of the cases can survive to full term, while the majority die at different gestational ages within the abdominal cavity. Their soft tissues are absorbed, while the bones remain, or become mummies or petrified. There may also be abscesses formed due to secondary infection,溃破to the surrounding tissues, such as the umbilical cord of the mother, intestines, vagina, etc., leading to the excretion of fetal hair and bone fragments, which are quite helpful for diagnosis.

　　In addition to general symptoms, it can also cause other diseases. This disease can be complicated with infection, fever, abdominal abscess, and peritonitis. Therefore, once discovered, active treatment is needed, and preventive measures should also be taken in daily life.

　　The age of patients with abdominal pregnancy is often greater than the average age of parturients, and they have fewer previous births. In the early stage, there are symptoms of tubal pregnancy, such as amenorrhea, vaginal bleeding, early pregnancy reactions, and abdominal pain. Most of them have a history of a relatively obvious abdominal pain. It is caused by the abortion or rupture of tubal pregnancy. After that, the abdominal pain subsides and the abdomen gradually increases in size. During the pregnancy process, discomfort in the abdomen is common, with symptoms such as nausea and vomiting, constipation, diarrhea, and abdominal pain. Abdominal pain can be manifested as obvious during fetal movement, disappearance of fetal movement, and subsequent disappearance of abdominal pain. In the late pregnancy, the patient may appear symptoms of false labor. Some patients may have more internal bleeding due to tubal pregnancy abortion or rupture, and may have symptoms of anemia. If the fetus dies prematurely, the abdomen will gradually shrink, fetal movement will disappear, and it may not be noticed by the patient. However, when examined for other diseases, a mass in the abdominal cavity can be found.

　　If the placenta is attached to the intestine or if the fetus compresses the intestine, it can cause intestinal obstruction symptoms; if the fetus dies and infection occurs, high fever may not subside, and after the formation of abscesses, they can be drained through abdominal or intestinal perforation, and the fever can decrease only when the pus is discharged. At the time of pus discharge, the fetus's bones and hair can be seen.

　　During the examination, if the fetus is alive, the fetal limbs and movements can be clearly felt under the abdominal wall, and the position is mostly transverse, with the presenting part often located above the pelvic inlet. Below the fetus, a round-shaped mass can be felt, which is the uterus. During vaginal examination, the cervix can be seen to be pushed to one side. The uterus has increased to the size of 2 to 2.5 months of pregnancy, and lumps of different sizes can be felt around the uterus, which may be the fetal head, body, or sometimes a soft mass can be felt in the deep pelvis, which is the placenta.

　　If the fetus survives, the most typical and diagnostic sign is to hear maternal vascular杂音, which comes from the dilated and thickened ovarian artery supplying the ectopic placenta. This vascular murmur is louder than that of the uterine artery and is often heard on the side where the placenta is implanted, inside the iliac spine in the abdomen.

　　In recent years, the incidence of ectopic pregnancy has shown an increasing trend. This is an important issue facing us. Although the exact etiology of abdominal pregnancy is not yet fully clear, many related factors are well understood. Reducing the high-risk factors can achieve the purpose of prevention.

　　1. Strengthen the publicity and social governance of the prevention and treatment of sexually transmitted diseases.

　　2. When inserting an intrauterine device or performing an induced abortion, strict adherence to operational protocols and infection prevention measures is crucial.

　　3. Pelvic soft tissue infection should be treated early and cured thoroughly in one go.

　　4. Actively treat endometriosis.

　　4. After using ovulation-inducing drugs, if early pregnancy is suspected or assisted conception is successful, it is necessary to promptly exclude ectopic pregnancy and multiple pregnancies.

　　5. Publicize the dangers of smoking and prohibit drug abuse.

　　First, laboratory examination

　　Peripheral blood:Anemia can lead to decreased hemoglobin and red blood cells, and infection can increase white blood cells and neutrophils.

　　Second, auxiliary examination

　　1. Ultrasound examination:The uterus is uniformly enlarged to the size of 2-3 months of pregnancy, with an empty uterine cavity; the fetus can be seen outside the uterus from any stage to full term. Surviving fetuses show fetal heartbeats, while dead fetuses show deformed fetuses, overlapping skull bones, less amniotic fluid, etc. The placenta is attached to other organs or tissues. Placing a probe in the uterine cavity during an ultrasound can also assist in diagnosis.

　　2. Abdominal X-ray imaging:For abdominal pregnancy around 20 weeks or more, abdominal X-ray imaging can help with diagnosis. In live fetuses, the fetus is often in a transverse position with abnormal limb extension; in dead fetuses, the fetal head is deformed, limbs are twisted, and the spine is malformed. In the lateral view, the fetus is often located below the abdominal wall, covering the mother's spine. The soft tissue of the uterus and placenta is not clearly visible. If MRI or CT examination is available, it can show that the fetus and placenta are located outside the uterus.

　　3. Uterine iodine oil contrast imaging:In cases highly suspected of abdominal pregnancy, uterine iodine oil contrast imaging can also be performed. If the fetus is located outside the uterine cavity, it can be diagnosed as abdominal pregnancy; it should be noted that at this time, the uterine cavity has expanded, and 10ml of iodine oil may not be enough to fill the uterus, and 20-30ml may be needed.

　　4. Oxytocin Stimulation Test (OCT):Intravenous small-dose infusion of oxytocin, without uterine contraction response, and the uterine contour cannot be seen on the abdominal wall.

　　According to different symptoms, there are different dietary requirements. Different dietary standards should be formulated for specific diseases. The diet of patients should be light and easy to digest, with an emphasis on eating more vegetables and fruits, and a reasonable diet. Pay attention to sufficient nutrition. In addition, patients should also pay attention to avoiding spicy, greasy, and cold foods.

　　The management of abdominal pregnancy is relatively complex. Due to the accumulation of experience and the improvement of surgical methods, Stevens et al. (1993) reported that the maternal mortality rate has decreased from 20% to 5% in the past 20 years.

　　The presence of the fetus in the abdominal pregnancy can lead to infection, abscesses, and sinus tracts. Therefore, once the diagnosis is confirmed, surgical treatment should be considered. The main key to the surgery is the management of the placenta, improper management of which can lead to massive bleeding at the placental attachment site and damage to organs. Therefore, the method of management should be decided according to the placental attachment site, whether the fetus is dead, and the duration of death.

　　If the fetus inside the abdominal cavity is not removed by surgery, the following situations may occur: ①residual fetal bones, absorption of soft tissue; ②formation of adipocere; ③formation of stone fetus or calcification; ④infection, necrosis, and abscess formation of fetal tissue; ⑤if the fetal tissue remains in the abdominal cavity for a long time, it can penetrate into the bladder and rectum, forming abdominal fistulas and other conditions.

　　Some authors advocate the use of methotrexate to destroy the remaining placenta. The mechanism of action is that methotrexate can destroy the trophoblastic tissue, reduce the blood supply of the placenta, promote its degeneration and necrosis, and HCG can be reduced to normal levels. The disadvantage of using methotrexate is that the destroyed placental tissue left in the abdominal cavity is a good bacterial culture medium, which may lead to complications such as concurrent infection, peritonitis, abdominal wall wound dehiscence, pelvic abscess, sepsis, and even death in severe cases. In cases where methotrexate is not used, although the absorption of the placenta is slower, the recovery period of the patient is delayed, but the complications are fewer.

　　1. Blood must be prepared before surgery, and intestinal preparation must be done well.

　　2. If the fetus is alive or has been dead for a short time, remove the fetus, ligate and cut the umbilical cord at the umbilical cord attachment site on the placental surface, and leave the placenta in the abdominal cavity. At this time, the placental implantation surface is closely adhered to the abdominal organs or tissues, with abundant blood sinusoids, and bleeding can occur during stripping. The retained placenta may be organically absorbed. If it is not absorbed, consider the surgical treatment plan in the future.

　　3. If the fetus has been dead for a long time, such as for several weeks or months, and the placental implantation area is not large, the placenta has shrunk, and most of the blood sinusoids have closed, it can be tried to strip and remove the entire placenta. Generally, there is not much bleeding.

　　4. If the placenta is planted on the omentum, the omentum can be removed together, but if it is planted in the pelvic cavity, it is strictly forbidden to forcefully remove it, as the bleeding is difficult to control. There have been reports that scholars who plant the placenta at the pelvic floor first perform percutaneous femoral artery pelvic angiography and then perform internal iliac artery embolization before surgery to significantly reduce the amount of bleeding. If massive bleeding occurs during surgery, this method can also be used to stop bleeding.

　　In recent years, there have been reports that placental retention during surgery can lead to infection, abscesses, non-healing wounds, and intestinal obstruction. There have also been reports of maternal pyelonephritis and even persistent preeclampsia for 99 days until the placenta was removed and cured. However, compared with the risk of massive bleeding during surgery, most scholars still hold the opinion of postoperative placental management. If the placenta is retained in the abdominal cavity, it can be observed for the decrease of serum β-HCG, and most of them decrease rapidly, but Belfar et al. (1986) reported that the absorption time of the placenta can last up to 5 years.