Induction of Labor

I can't believe I haven't written on this subject before.  The daughter of a friend of was being induced today.  I wanted him to read about induction of labor and then realized I had never written about it!

According to ACOG, the American College of Obstetricians and Gynecologists, induction of labor is the use of medications or other methods to bring on (or induce) labor. Labor is induced in about 20% of women in the United States. The American Association of Family Physician sites the rate as between 9.5 and 33.7%, depending upon the area.  Obviously, in some areas there are more inductions and in others there are fewer.

The same methods can be used to speed up labor if it is going too slowly, but this is usually referred to as augmentation, instead of induction of labor.

REASONS WHY LABOR MIGHT BE INDUCED

Labor might be induced if conditions exist which put your health or the health of the baby at risk.  For the health of some women, having the baby is safer than continuing with the pregnancy.  For the health of some babies, the environment outside the uterus may be safer than the environment inside the uterus.  Reasons for inducing labor may include one or more of the following conditions:

• The pregnancy has lasted more than 42 weeks, or is postterm
• The mother has pregnancy-induced hypertension
• The mother is a gestational diabetic
• There is an infection in the uterus
• The mother has premature rupture of membranes (meaning the water has broken several hours before labor has begun)
• The baby's growth rate has slowed down considerably and is now considered IUGR
• The level of amniotic fluid is significantly decreased, called oligohydramnios

There may be other reasons for inducing labor.  For example, occasionally a woman may be induced if she lives a long distance from the hospital or if she has a history of very rapid labors.

HOW DOES MY HEALTH CARE PROVIDER DECIDE I NEED INDUCTION?

The decision for induction is based upon the need for induction, such as the factors listed above, as well as how far along your pregnancy is and the status of your cervix. Unless there is a significant risk factor or problem, labor is not induced before 39 weeks of pregnancy.

WHAT DOES MY CERVIX HAVE TO DO WITH IT?

Labor is the process by which contractions of uterus thin out and open up (or dilate) the cervix so that the baby can pass through.  At the end of pregnancy, hormones cause the cervix to become soft and able to thin out during labor.  This is called "ripening".  A health care provider may often refer to a cervix that is not yet soft as being "green", like a piece of un-ripe fruit. If the cervix has not yet "ripened", it will not be conducive to the induction agents used. 

If your cervix is not favorable for induction, your health care provider may decide to use an agent to help ripen your cervix.  There are dilators which can be inserted into the cervix which mechanically soften it.  There are also certain medications which can be used.

Prostaglandins are drugs that can be used to prepare the cervix for labor. They are synthetic forms of the same chemicals produced naturally by the body. They can be inserted into the vagina or taken by mouth.

A way of causing your body to release prostaglandins is called Stripping the Membranes.  During this procedure, your health care provider checks your cervix with a gloved finger.  He or she sweeps the finger over the thin membranes that connect the amniotic sac to the wall of the uterus.  After this is done you may notice some cramping and may even have some spotting.  The release of prostaglandins this causes can result in a softening of the cervix.  It can also cause contractions.  This is usually done in the doctor's office, or in the hospital.

INDUCING LABOR

Rupturing of the Amniotic sac is a way to attempt to start contractions.  Your health care providers can make a small opening in the amniotic sac during a vaginal exam.  It is important to stay as relaxed as you can during this exam to minimize any discomfort.  This is usually done only after the baby's head has moved down in the pelvis.  Most women will begin contractions within a few hours of the rupture of membranes.

OXYTOCIN

Perhaps the most common form of artificially beginning contractions is the use of oxytocin.  Oxytocin, or also called Pitocin, is a medication used to induce labor.  It is a synthetic form of the same hormone produced by the pituitary gland in laboring women.  It can be used to induce contractions, or to increase the strength of contractions.

Oxytocin is administered into your vein through an IV.  A pump will control the amount that is given.  In most instances, Oxytocin is started off very slowly and increased at regular intervals to mimic natural labor.  Your contractions will be monitored carefully to make sure they are not lasting too long or coming too close.  If that should occur, the rate of the Oxytocin drip can be adjusted.

WHAT ARE THE RISKS OF INDUCTION OF LABOR?

Image via WikipediaEvery intervention has some risk factors, even those that seem the most benign.  Although problems rarely occur with inductions, there can be increased risks.  These may include:

• Changes in the fetal heart rate
• Increased risk of infection (which is true anytime you have an IV)
• Overstimulation of the uterus (contractions too close, or lasting too long)
• Umbilical cord problems,  (Labor induction increases the risk of prolapsed cord - the umbilical cord slipping into the vagina before delivery, which may compress the cord and decrease the baby's oxygen supply)
• Uterine rupture - a rare but serious complication in which the uterus tears open along the scar line from a prior C-section. An emergency C-section is needed to prevent life-threatening complications.

To avoid the problems, the fetal heart rate will be monitored continuously.  The duration and frequency and force of the contractions will also be monitored.

WILL I BE MORE LIKELY TO HAVE A CESAREAN SECTION?

There are conflicting studies on this question.  The answer for this is partially because of the great number of women who are induced also have risk factors which would predispose them to a Cesarean Section.  For example, a mother who has oligohydramnios, or a low level of amniotic fluid, may experience more fluctuations of the fetal heart rate during labor due to the compression of the umbilical cord by the contractions. 

A study done by Ochsner Clinic of women who had previously given birth, who were being induced for subsequent babies, showed there was little difference in the Cesarean Rate for those who were induced and those in the control group.  When women who have never had babies before are added into studies, then the risk of having a C-Section appears to increase.  The key factor is the favorability of the cervix prior to the initiation of the induction agent.  The more favorable the cervix, the greater the likelihood of a vaginal delivery.

CONCLUSION

The decision of whether or not to induce labor must be made between you and your health care provider.  All risk factors of mother and baby, the risks of the procedure as well as the perceived benefits must be discussed.

Be sure that you ask questions, and that you understand the answers fully.  Don't be afraid to say you didn't understand. If you feel as if you need time to "think it over", ask if you can take that time.

The majority of inductions occur each day in our country without any problems.  If you decided upon an induction, throughout the process you can ask your nurse any questions that might arise.  She will be happy to keep you informed of your progress, the process and your baby's status.

Keep in mind the goal of a healthy mother and a healthy baby and look forward to being a mother!