In recent years, due to the increasing pressure of people's life, increased exposure to electronic equipment radiation and other factors, infertility patients showed an obvious upward trend. The development of assisted reproductive technology has brought hope for infertility patients, so that infertility patients have the opportunity to conceive their next generation. Globally, in vitro fertilization and embryo transfer (IVF-ET) technology generally transfers 2 or more embryos at a time to improve the pregnancy rate, but it also increases the probability of multiple pregnancy and ectopic pregnancy . There are many causes of ectopic pregnancy, including abortion history, pelvic inflammatory disease, intrauterine device, fallopian tube factors . At present, it is recognized that the main cause of infertility and HP after assisted reproductive technology is fallopian tube dysfunction caused by fallopian tube lesions . In this study, 45 cases of 47 patients were conceived by IVF due to tubal factors, 13 patients had a history of ectopic pregnancy and 32 patients had a history of intrauterine operation. Embryo transfer is to put the embryo directly into the uterine cavity with the transfer tube. The embryo entering the uterine cavity still needs to swim for about 3 days. It is completely embedded in the endometrium after three processes of localization, adhesion and invasion, while some embryos swim into the fallopian tube. If some pathological changes of fallopian tube or pelvic cavity lead to abnormal peristaltic function of fallopian tube, such as damaged fallopian tube epithelium, narrow lumen, loss of cilia or hydrosalpinx, the embryo is easy to stay in the fallopian tube for implantation and development, resulting in tubal pregnancy.
In the natural physiological state, the embryo development is synchronized with the "implantation window" of the endometrium . In IVF-ET, the time of embryo transfer into uterine cavity in cleavage stage was 2 to 3 days earlier than that in natural pregnancy Three days later, the embryo can not be implanted in the uterine cavity immediately. Under the action of oviduct peristalsis, cilia swing and corpus luteum, most of the embryos will move back to the uterine cavity, but some of them can migrate outside the uterine cavity to produce ectopic pregnancy . Previous studies have shown that the ectopic pregnancy rate in blastocyst transplantation cycle is lower than that in cleaved embryo transplantation cycle . In this study, among the 47 patients with HP after embryo transfer, 18 were at the cleavage stage on the 3rd day, 6 were blastocysts on the 5th day, and 23 were frozen thawed embryos. In addition to the above reasons, the occurrence of ectopic pregnancy is also related to the volume of transfer fluid, injection pressure and the depth of embryo from uterine cavity during transfer .
When ectopic pregnancy occurs, β-HCG often does not double well, and progesterone level is generally 10-25ng/ml lower than intrauterine pregnancy. Transvaginal ultrasound is the main examination method, the choice of treatment method for ectopic pregnancy should be combined with HCG level and B-ultrasound results, Expectant treatment, MTX embryo killing treatment and surgical treatment can be adopted. However, due to the existence of intrauterine pregnancy, the HCG value of HP is similar to or higher than that of intrauterine pregnancy, and the level of progesterone is similar to intrauterine pregnancy. If intrauterine pregnancy is found by ultrasonography, it is easy to be missed if the ultrasonographic features of ectopic pregnancy are not typical. When HP occurs, the HCG level is often high, the embryo has a strong activity, and the risk of ectopic pregnancy rupture is significantly increased. If the ectopic pregnancy embryo is found too late, it will not only affect the outcome of intrauterine pregnancy, but also cause hemorrhagic shock due to the rupture of ectopic embryo, which will threaten the lives of patients. Therefore, for patients with assisted reproductive technology pregnancy, even if intrauterine pregnancy is found, we should carefully check the situation of ectopic embryos. Study has reported that the β-HCG level on day 14 (HCG14) and day 21 (HCG21) was higher than 290mIU/ml and 2790mIU/ml respectively, with the decrease of HCG21 / HCGl4 ratio ranging from 10-15 .
Typical clinical symptoms of HP are similar to those of ectopic pregnancy, including abdominal pain, irregular vaginal bleeding, peritoneal irritation and uterine enlargement . In this study, all patients were after embryo transfer, and they paid more attention to vaginal bleeding, abdominal pain and other clinical manifestations than patients with natural pregnancy. They all went to the hospital earlier for examination and treatment, and the diagnosis time was 19-104 days after embryo transfer. Immediate hCG and B-ultrasound examination made the signs of HP mild, in our research, there are 32 patients had clinical symptoms while 15 cases had no clinical symptoms. So TVS is an important basis for the diagnosis of HP . Typical ultrasound findings of HP: gestational sac can be seen in the uterine cavity, and the echo of gestational sac can be seen outside the uterine cavity, but some HP were missed because of the lack of typical ultrasound findings . The ultrasonic manifestations of HP ectopic lesions can be divided into direct signs and indirect signs: the direct signs are the gestational sac, yolk sac, even germ and fetal heart with ectopic pregnancy; the indirect signs include mixed echo mass and abdominal pelvic effusion. The diversity of ultrasonic manifestations leads to the uncertainty of ultrasonic diagnosis [6,7]. Therefore, the diagnosis of HP should be combined with the patient's history, clinical manifestations and ultrasound findings. In particular, the first follow-up of B-ultrasound should pay attention to the presence of gestational sac like structure, mixed mass, abdominal and pelvic effusion. If the pregnant person has sudden abdominal pain, irritability and vaginal bleeding during pregnancy, it should be checked whether it is HP .
Patients with suspected HP should be hospitalized as soon as possible. In 47 cases of HP patients in our hospital, the median intervention time was 48 days. Intraoperative visual observed that gestational sac size was 3.78±1.31 cm. Previous studies have found that the probability of have better pregnancy outcome the laparoscopic treatment is higher than that of conservative treatment patients in HP. Conservative treatment avoids the risks associated with surgery, however, conservative treatment of HP patients with ectopic pregnancy mass rupture rate of 20%. Therefore, For HP patients with high HCG and obvious clinical symptoms, laparoscopic surgery should be used as early as possible, and the best treatment time is before 6 weeks, but not before 4 weeks, too early surgical treatment can easily lead to abortion. For the postoperative patients, routine use of fetal drug. To extend the pregnancy week of intrauterine pregnancy as far as possible when the patient's vital signs are stable.