Evidence-Based Medicine: Is Induction Necessary?

During my last month of pregnancy, I had a few “false alarms,” where I was convinced I was in labor, but it turned out I wasn’t.  I was so anxious to meet Sweet Pea, a little nervous about what labor would actually feel like, and it started to do weird things to my brain.  After our third false alarm, my husband and I finally sat down and accepted the reality that we had no control, and that Sweet Pea would come when she was ready.  We knew that every day she “cooked,” the healthier she would be.  I went to bed that night at peace, knowing that the best thing I could do for her was to be patient.  The next morning, I woke up in labor – at 39 weeks on the nose.

Many first time mothers experience the same kind of anxiety and anticipation that I did, but the weeks stretch on an on, even surpassing their due date.  And those women and their doctors are talking more and more about artificial induction, using labor-stimulating drugs like Pitocin.  A study from 2006, featured in the New England Journal of Medicine, found that 40% of low-risk, first time mothers were induced into labor.

Induction is definitely a growing trend in America.  But is this trend necessary to improve the outcomes for mothers and babies?  Are there situations where induction is medically indicated?  And how much of this trend is based on convenience — either for the mother or doctor?

When is induction medically necessary, improving the outcomes for mothers and babies?

According to Ina May Gaskin’s Birth Matters, up to 10% of all labors may call for labor induction.  She lists specific circumstances that may call for induction, such as:

  • cancer
  • hypertension
  • diabetes
  • kidney disease
  • IUGR (intrauterine growth restriction)
  • significant decrease in amniotic fluid
  • intrauterine fetal death (followed by a long (weeks, not days) wait for labor to begin)

Marsden Wagner (perinatologist, and author of Born in the USA) adds two other conditions:

  • documented placental malfunction (placenta losing its ability to nourish the fetus)
  • deteriorating preeclampsia (high blood pressure during pregnancy)

According to Gaskin and Wagner (both specialists in their fields), under these conditions, induction actually improves the outcome (as opposed to spontaneous labor).  But they both state that only about 10% of all pregnancies need to be medically induced.  And when you add up the statistics for each of the above circumstances, it comes very close to 10% of pregnancies.  But, according to Childbirth Connection‘s 2005 Listening to Mothers Survey, half of all pregnant women experience induction.  So why the major discrepancy?

You may notice that two of the most commonly-given reasons for induction — postdate (overdue) pregnancy and big babies (macrosomia) — are not listed.  This may explain the difference in recommendation versus reality.  Let’s see what the evidence says about those two reasons.

Induction Due to Post-Dates (Overdue)

This is the normal distribution for gestational age.  Notice when the largest majority of babies are born — 40-41 weeks.  And approximately the same percentage give birth between 41-42 weeks as do 39-40.   And this is all with spontaneous labor!

I think this about says it all.

Normal, low-risk pregnancies go to 40 weeks and beyond quite often.  First time mothers are especially likely,.

What about the risks of going past 42 weeks?  Isn’t there a risk to the baby?

According to Wagner, a study from 1963 found that a slight increase in the number of stillbirths after 42 weeks, with a significant increase after 43 weeks.  This study has been frequently cited as evidence to support induction before 42 weeks.  But Wagner puts the risk to the individual woman into perspective —  as it turns out, only 3 percent of pregnancies even extend beyond 42 weeks, and even after 43 weeks, only 10 percent (of that 3%) have any problems.  So as you can probably deduce, the chances of going so far past your due date that you put your baby at risk is pretty insignificant (about 0.3%).  You have a much greater chance of going into labor spontaneously before you reach 43 weeks, and an even if you don’t, there’s a good chance your baby will still be born healthy.

Another risk in induction due to postdates is the inaccuracy of EDDs (Estimated Due Dates).  Because of normal variations in the menstrual cycle length amongst average women, and the tendency to base due date on the last menstrual period (LMP), a woman’s due date could be off by 2 weeks or more.  So if a woman gets induced at 40 weeks, her baby could actually only be 38 weeks (or less), which is associated with more health problems for the baby.  This is a phenomenon called iatrogenic prematurity (essentially, doctor-caused prematurity), and is a growing portion of the increasing prematurity rates.

So, post-dates is generally NOT a medically indicated reason to be induced.

“Big Babies” or Fetal Macrosomia

First, macrosomia is defined as a baby weighing over 8 lbs 13 oz.  It legitimately effects about 10% of all pregnancies in America.

Perhaps the one of the most prominent concerns about big babies is a complication called “shoulder dystocia,” where the baby’s shoulders get stuck on the mother’s pelvic bone.  The risks of this complication include paralysis, Erb’s palsy, and fetal hypoxia (baby doesn’t get enough oxygen). Sounds scary, doesn’t it?  And if you are of the unfortunate 1% of women who experience it, it will definitely be treated as scary in the typical US hospital.

So what happens when a woman experiences shoulder dystocia?  Just think ALARMER.

  • Ask for help. This involves requesting the help of an obstetrician, anesthesia and pediatrics for subsequent resuscitation of the infant.
  • Leg hyperflexion (McRoberts’ maneuver)
  • Anterior shoulder disimpaction (suprapubic pressure)
  • Rubin maneuver
  • Manual delivery of posterior arm
  • Episiotomy (Does anybody else wonder how cutting open the perineum has any impact on a baby who is stuck on the pelvic bone?  Okay good, me either.)
  • Roll over on all fours

According to Wikipedia, the advantage to this mnemonic is that it goes from least invasive to most invasive.  That sounded all fine and good, until I got to the last method — roll over on all fours.  Wait, what??  How is rolling over on all fours less invasive than say, an episiotomy (you know, where they cut your perineum)?

Turns out “Roll over on all fours” has a name — Gaskin’s maneuver, and was discovered by midwife Ina May Gaskin (yes, the same one mentioned earlier).  This maneuver opens the pelvis (wider than lying on her back) , allowing the shoulders to slide through. Sounds pretty non-invasive.  In one study, the Gaskin maneuver had the following results:

“Half of the eighty-two babies weighed more than 4000 grams (about 8.5 pounds); 17 or 21 percent weighed more than 4500 grams (about 8 pounds, 10 ounces); thirty of the 1-minute Apgar scores were less than or equal to 6, and two were less than or equal to 3; only one of the 5-minute Apgar scores was less than or equal to 6, which is 1.2 percent; forty-nine of the women or 60 percent delivered over an intact perineum, and there were no third- or fourth-degree lacerations; one woman had postpartum hemorrhage not requiring transfusion; and one infant had a fractured humerus.

That sounds a heck of a lot better than an episiotomy to me.  So why aren’t more hospitals using this technique?  Probably the biggest reason is that movement during labor is limited by current birth practices, such as epidurals and electronic fetal monitoring, which generally require the mother to lay on her back.

Another issue with justifying induction because of macrosomia is the accuracy of the diagnosis.  Macrosomia is generally diagnosed using an ultrasound, which has been found to be inaccurate in nearly two-thirds of cases.

And according to Wagner, while macrosomia has been used to justify induction, evidence does not support this practice.  In fact, C-Section rates increase with induction due to macrosomia, with NO improvement in outcomes.  As he puts it in Born in the USA, “trying to hammer out too large a baby can harm the baby.”

Conclusion:

  • Evidence suggests that induction rates of less around 10% are essential to optimal outcomes for mothers and babies.
  • About 50% of pregnant women experience induction in the US.
  • Gestational ages range, and 42+ weeks pregnancies can still be healthy and deliver spontaneously.
  • Due dates can be up to 2 weeks off.
  • Big babies have a higher risk (1%) of developing “shoulder dystocia,” which has serious complications.
  • Diagnoses of macrosomia can be inaccurate up to two-thirds of the time.
  • If you induce due to macrosomia, you have a greater risk of undergoing a C-section

Oh, and:

  • Episiotomies widen your vagina (skin/muscle), not your pelvis (bone).  Just say “no” to episiotomy.
  • Patience is key.

With all that I’ve read, I have to say I come down on the side of “very wary” of induction.  Unless you are in the 10% whose medical condition requires it (see above), it’s probably better for you to wait until your baby is good and ready to come out.

Here are some more natural ideas for inducing labor:

  • Walk.  A lot.  — I walked more in the last month of my pregnancy than I did in the previous 8 months combined.  Which was nice, since I couldn’t walk farther than 4 feet without pain for about a week after she was born.
  • Have sex.  A lot. — As awkward as it sounds, the prostaglandins in semen help soften the cervix.  And it might sound a little dirty, but let’s admit it, that’s how we all got into this predicament to start with.
  • Start a lengthy project.  — Not only does this fill your time, but you are almost guaranteed that your baby will come before you can finish it.
  • Buy expensive concert tickets for right around your due date.  — Along the same vein, it’s likely that you won’t get a chance to use them.

HAPPY WAITING!

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4 Comments on “Evidence-Based Medicine: Is Induction Necessary?”

  1. Laura Bly says:

    Love this. So many women just want to “have it over with” and don’t take into account that they are putting their baby at risk. I always thought (natural) birth was a good preparation for parenting–it’s not going to happen on your schedule, and you have to die to your selfish desires. I heard someone describe the culture of medical interventions during birth like this: “The next time my OB poops, I’m going to stand over him with a stopwatch and tell him he’s not progressing quickly enough. Then, lay him on his back, give him an epidural and pull that thing out with salad tongs.”

  2. Mother of Fact says:

    What a wonderful point. Birth certainly does shape you as a person, and can definitely prepare you for parenthood, if you approach it with patience and selflessness. I have often thought the very same thing.

    I also love the analogy you gave. Did you see the video, “Failure to Progress?” You might enjoy it.

  3. […] like epidurals, augmentation, and induction when doctors talk about the “risks” (like hypersomia and shoulder dystocia).  This right is especially poignant during labor, when a woman is experiencing the effects of lots […]

  4. […] couple weeks back, I researched the necessity of labor induction.  I learned that, according to the Listening to Mothers Survey from 2005, about 40% of all labors […]


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