In vitro fertilization and embryo transfer (IVF-ET) is often called “in vitro fertilization” in our country, and these children are also grown in the mother’s womb. In general, IVF technology is safe, but some complications may occur. The following are the complications of IVF. Ovarian torsion After ovulation, the ovaries are obviously enlarged, and after egg retrieval, multiple corpus luteum are formed, and the ovaries are also very large. At this time, if a woman moves vigorously or changes her posture rapidly, it may lead to ovarian (adnexal) torsion, which is manifested by severe pain on one side of the lower abdomen and may be accompanied by nausea and vomiting. Therefore, you must not engage in strenuous activities before and after egg retrieval. Although IVF involves transferring embryos into the uterus, the fallopian tubes secrete chemokines that induce embryos to wander into the fallopian tubes for implantation and development, resulting in ectopic pregnancy. Sometimes embryos are also implanted in the cervix, cesarean scar, etc. The incidence is about 3%. It can be seen that ectopic pregnancy can occur in IVF, just like natural pregnancy. Ovarian hyperstimulation syndrome (OHSS) is caused by the growth of multiple follicles and very high estrogen levels in the body, which increases vascular permeability and causes protein and fluid to leak into the abdominal and thoracic cavities, resulting in thoracoabdominal fluid and blood concentration in the blood vessels. The incidence is about 10% and occurs mainly in women with good ovarian reserve function. Most people have mild symptoms, such as abdominal distension, abdominal discomfort and mild nausea, which can be left untreated; however, a small number of people will have severe abdominal distension, oliguria, poor appetite, and even chest tightness and shortness of breath, and it is recommended to be hospitalized for close observation and treatment. Very few people may experience renal failure, cerebral embolism, etc. IV. Multiple pregnancy The rate of multiple pregnancies due to IVF technology is significantly higher than that of natural pregnancies, about 25-30%, because multiple embryos are transferred to the uterus at one time. The risk of obstetric diseases in multiple pregnancies is significantly higher, such as late miscarriage and preterm delivery, and the risk of gestational diabetes, gestational hypertensive disorders, obstructed labor and postpartum hemorrhage in mothers is significantly higher than in singleton pregnancies. Therefore, multiple pregnancies are detrimental to both mother and child. Many IVF centers are now trying to reduce the rate of multiple pregnancies by minimizing the number of embryos transferred or by performing selective single embryo transfer. In cases of three or more pregnancies, reduction is mandatory, while in cases of twin pregnancies, patients are advised to reduce the number of embryos. V. Side injuries caused by egg retrieval 1. If the patient’s ovaries are poorly positioned, the puncture needle may need to pass through the bladder, causing bladder injury. Patients may experience temporary hematuria, which can be recovered relatively quickly. 2. Occasionally, the intestinal canal or blood vessels in the pelvis may be punctured. 3.Ovarian bleeding: In a few cases, the punctured ovary will continue to bleed, sometimes even requiring open abdomen to stop the bleeding. 4.Pelvic infection.