Why does incomplete abortion occur during artificial abortion?

Incomplete abortion refers to the fact that the embryonic tissue is not completely sucked out during artificial abortion, and there are residual embryonic tissues in the uterus. These tissues are either free in the uterine cavity or still attached to the uterine wall, resulting in excessive bleeding in the operating room or after surgery, and prolonged bleeding time.

Possible causes of incomplete abortion include:

① The operator is not skilled in the technique and has an inaccurate grasp of the size and position of the uterus. He has no sense of whether the uterine cavity has been sucked or scraped clean, which can easily result in part of the embryo or chorionic tissue not being sucked or scraped clean.

② Uterine malformations such as uterine septate, didelphys, saddle-shaped uterus, and bicornuate uterus are difficult to operate on and may sometimes result in incomplete abortion.

③ Uterine fibroids complicated with pregnancy, especially submucosal fibroids, cause irregular uterine cavity and make surgical operation difficult.

④ The implantation site of the fertilized egg is special, such as at the bottom of the uterine cavity, which is not easy to be fully touched by the straw and scraper.

⑤ The negative pressure is too high, which stimulates the uterine muscle wall to contract irregularly, forming a narrow ring in a certain part of the uterine cavity, leaving tissue residue.

⑥ The negative pressure is too low, the rubber tube is too soft, and the straw is too thin, resulting in insufficient suction. This will not only easily lead to prolonged operation time and increased bleeding, but also easily cause incomplete abortion.

⑦ The operation was not performed according to the routine steps. Before the operation was over, the scraping was not carefully checked to see if it was completely clean, especially the uterine horns on both sides. The scraping was not checked to see if it was complete and whether it was consistent with the month of pregnancy. Incomplete abortion can be manifested as excessive uterine bleeding during or after the operation, which lasts for a long time. Sometimes poor uterine involution may be found, and sometimes necrotic placental tissue may or may not be seen when the cervix is ​​opened. The radioimmunoassay of human chorionic gonadotropin in the blood did not drop to normal levels 3 weeks after the operation.