Artificial induction is more suitable for mid-pregnancy

Commonly used methods of artificial induction of labor include: rivanol induction, water bag induction, trichosanthes induction, guanhua induction, prostaglandin induction, hypertonic saline induction, alcohol induction, and chlorhexidine induction. Hypertonic saline induction, alcohol induction, and chlorhexidine induction are rarely used in clinical practice.

Artificial methods to terminate pregnancy between 14 and 24 weeks are called artificial (mid-term) induction of labor. Compared with early pregnancy, mid-term pregnancy has the following characteristics:

During mid-pregnancy, the mother is insensitive to uterotonic agents and uterine contractions are not easily induced. This is related to the fact that the placenta secretes a large amount of estrogen and progesterone, and progesterone inhibits uterine muscle contractions.

During pregnancy, there are often residual villi when the placenta is delivered, and it is difficult to check whether it is complete. Although the placenta has been formed, the smooth villi have partially degenerated, while some still have villus structures. At this time, the true decidua has not completely degenerated and is still relatively thick. Therefore, uterine curettage is generally required after abortion.

During the second trimester, the cervix needs to be fully dilated when the fetus is delivered, just like full-term delivery. Because the fetus grows and develops during pregnancy, the bones are formed and gradually increase in size and hardness, making it difficult to force the fetus to be delivered. Instead of mechanically dilating the cervix to force the fetus to be delivered, cervical ripening drugs can be used before surgery to promote cervical softening and dilation.

Due to the above characteristics, artificial (mid-term) induction of labor is difficult and has many complications. The uterus grows larger month by month, the uterine muscle wall becomes thinner, softer, and congested, which can easily lead to uterine perforation. Inadequate preparation of the cervix can easily cause tearing. There are also reports of posterior fornix injury. It may even endanger the life of the pregnant woman. Therefore, mid-term induction of labor should be avoided except in special circumstances.