Induction of labor
Induction of labor means that after 12 weeks of pregnancy, due to maternal or fetal reasons, it is necessary to artificially induce uterine contractions to terminate the pregnancy. According to the gestational week at the time of labor induction, it can be divided into mid-term labor induction (14-28 weeks) and late-term pregnancy induction (after 28 weeks).
Preparation before induction
The success of labor induction is related to various factors. Cervical maturity is an important factor in determining the success of labor induction. Immature cervix, induction of labor is often not easy to succeed. Most people with a mature cervix can give birth vaginally.
1. Cervical score
In 1964, Bishop developed a scoring system to determine whether pregnant women were suitable for selective induction of labor. At present, the commonly accepted method for estimating cervical maturity is the Bishop score. He believes that a score ≥ of 7 points indicate cervical maturity. The higher the score, the more mature, the easier it is to induce labor. If the score is below 6 points, cervical ripening should be promoted.
2. Methods to promote cervical ripening
The cervix is mainly composed of epithelium, smooth muscle, hoof tissue, glands and stroma. Cervical maturity is not necessarily proportional to the gestational age, but is related to the biological changes of the cervical tissue. After pregnancy, cervical tissue changes, which are obvious as the pregnancy progresses, and reach the peak during childbirth. The typical manifestations are: collagen fibers are significantly reduced and loose and meshed; blood vessels are engorged and hyperemic; white blood cells accumulate and adhere to the wall, and a large number of interstitials appear Of white blood cells and fibroblasts. Cervical maturation may be the result of a variety of hormones, such as estrogen, progesterone, relaxin and prostaglandin.
Methods of Induction of Labor Voice
The ideal method for promoting cervical ripening is similar to its natural ripening process. It does not cause excessive uterine contraction, does not affect uterine blood flow, and does not endanger the safety of the fetus and mother. There are many ways to promote cervical ripening, but there is no perfect and very effective method yet. At present, the commonly used methods are divided into two categories: non-drug and drug-based:
1. Non-pharmaceutical methods
①Artificial membrane peeling (basically not used); ②Artificial membrane rupture (not effective when used alone); ③Water bladder or Foley catheter (unconventional use); ④Hygroscopic expansion or Lamicel stick (used sparingly); ⑤Nipple irritation ( Not commonly used); ⑥ Acupuncture therapy (basically not used).
2. Drug therapy
①Oxytocin, low-dose and low-concentration intravenous drip; ②Prostaglandin PGE2 (conventional use); ③PGE2 gel intracervical administration (rarely used); ④PGE2 vaginal controlled-release tablets-Probexen (commonly used); ⑤Misoprost Alcohol (unconventional use); ⑥ vaginal misoprostol; ⑦ carbogestation suppository (basically not used); ⑧ mifepristone (not used for late induction of labor).
Wang Chenhong. The application of mifepristone in labor induction. "Chinese Journal of Practical Gynecology and Obstetrics", 2002
Liu Jie, Wang Jingyun. Induction and induction of labor in scarred uterine pregnancy. 2002
Wang Dezhi. The methods and precautions of oxytocin inducing labor and inducing labor. "Chinese Journal of Practical Gynecology and Obstetrics", 2002
Dai Zhongying. Application of prostaglandins in the induction of labor in term pregnancy. "CNKI", 1999
Du Xiuying, Dai Mingyu. Application of misoprostol in the induction of labor in term pregnancy. "Chinese Journal of Practical Gynecology and Obstetrics", 2001