©Pregnancy bliss 2008

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Methods of labor induction

There are two principal ways of inducing labor. One or both may be used.

 

Prostaglandins (PGE2) are the chemicals used specifically to prime the cervix for labor. They also have an ‘oxytocic’ effect in that they stimulate the uterus and may bring about contractions. Prostin is the  commost brand of PGE2 employed for this. The generic name for Prostin is Dinoprostone.

 

Other related prostaglandins by the name of Misoprostol (PGE1) are increasingly in vogue for labor induction especially because of their higher versatility as they can be administered both vaginally and orally.

 

The second method of labor induction is that of amniotomy.                        

Amniotomy simply means rupturing the membranes or "breaking the waters". Both methods are, in most cases, used with a supplemented oxytocin drip.

 

 

 

 

The effect of prostaglandins on the cervix and uterus

During pregnancy, the cervix or ‘neck of the womb’ is firm and closed because its main function is to maintain the ever ­increasing size and weight of the contents inside the womb cavity. At term, before labor, the cervical function changes to facilitate smooth and safe birth.

 

To be able to do this, the cervix undergoes profound changes, whereby it becomes softer, thinner, shorter and distensible. These acquired characteristics allow it to open (dilate) when uterine contractions start.

Prostaglandins are used to bring about these changes to the cervix.

 

Administering prostaglandins to induce labor

The most popular method of administration is vaginal. It is mostly given in the form of a gel or vaginal suppositories (pessaries).  

 

Also available are steady-release devices, which are also inserted vaginally and can be retrieved instantly if the need arises. They are more expensive and rather less popular with obstetricians.

 

PGE1 (Misoprostol) oral tablets are also increasingly used especially for women who would prefer to avoid the vaginal route of labor induction. However, these are not universally available.

 

There is no place for intravenous prostaglandins in induction of labor.

 

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Misoprostol or PGE1 (above) van be administered both orally and vaginally. Prostin or PGE2 (below) is administered vaginally, usually in gel or tablet form

Steady-release vaginal inserts are available for both  Misoprostol  (Misopess™) and Dinoprostone (Propess™ or Cervidil®). Just another option for labor induction