Just Say “No” to Induction for Suspected Big Baby

Feb 28, 2025 | Wetenschap

 

Just Say “No” to Induction for Suspected Big Baby

 

When doctors believe a baby is going to be on the large side, they often recommend inducing labor in hopes of avoiding a cesarean or injury to baby or mom during a difficult vaginal birth. Does that strategy work?

In this blog post, we’ll look at the research showing that it doesn’t plus, in the “Takeaway” section, I’ll supply you with a list of physiologic care strategies that do.

Does the Research Support Precautionary Induction for Suspected Big Baby?

In order for precautionary induction to succeed at its intended goal, the following would have to be true:

  1. Doctors would need to be able to accurately identify which babies are going to be big. They can’t. “Big” is usually defined as weighing 8 lb 13 oz (4,000 g) or more. Ultrasound scans predicting that a baby will weigh more than 4,000 g will be right only 56 percent of the time.2 That means you have roughly a 50:50 chance of being induced for a problem you don’t have.

     

  2. Inducing labor would need to reduce cesareans. It doesn’t. For one thing, every study that has looked at outcomes when a baby is predicted to be big has found that when doctors think the baby is going to be big, the odds of cesarean go up markedly regardless of whether the baby is actually on the large side.3, 6, 11-13, 15-17, 19, 21, 22, 24-26 The reverse is also true: cesarean rates with babies who are big, but weren’t suspected to be big by doctors, are much lower. In other words, the probability of having a cesarean depends largely on what the doctor thinks the baby weighs, not the baby’s actual weight. For another, none of the studies that have looked at whether inducing for suspected big baby reduced cesareans have found that it did.4, 20, 23 In fact, one study found that inducing labor with a bigger baby markedly increased cesareans at first births.14 Separating first births from labors following prior vaginal births seems to have exposed a risk of inducing labor at first births that was masked in populations combining both. As to why the difference, cesarean rates are much higher at first births compared with having had a prior vaginal birth or births because first labors are much more vulnerable to factors that inhibit labor progress.

  3. Inducing labor would need to reduce birth injuries. It doesn’t do that either. The only protective effect of inducing for suspected big baby is a possible small reduction in the incidence of broken collarbone (0.3 percent vs. 2 percent),4 an injury that, while serious, will heal without further consequence. That protection is offset by a probable slight increase in the occurrence of maternal anal sphincter injury (1 to 2 more anal sphincter injuries per 100 deliveries),4, 14, 22-24 an injury that increases the probability of developing chronic incontinence of gas or stool.9 In other words, there is a possible modest reduction in infant fractures, which have no long term consequences, that is offset by an increase in maternal anal sphincter tears, which can.

So, in answer to the question of whether you should agree to induction for suspected big baby, the research says “no.” The prediction that a baby will weigh 8 lb 13 oz or more is likely to be wrong; inducing for this reason doesn’t reduce cesareans and probably increases them in first labors; and induction doesn’t reduce adverse outcomes in babies other than a small reduction in broken bones, which have no long-term consequence, at the cost of a small increase in maternal anal sphincter injury, which does.

    Your Take-Away

    Unfortunately, you have a problem whether you decide to agree to induction or wait for labor. If your care providers fear that you won’t be able to birth a bigger baby or birth one without injury, you’re already behind the 8-ball because it will affect their judgment and the calls they make based on their judgment. Here are some thoughts on how best to protect yourself:

    • If possible, switch to care providers who believe you can birth a bigger baby. They will also be more likely to have policies and practices that promote your ability to birth a bigger baby, e.g., encouraging mobility in labor and pushing and birth positions other than on your back, evaluating your progress on an individual basis, not according to rule, etc. To determine where your care providers stand, ask them about their care policies and practices when they think the baby may be bigger than average.
    • Take a set of childbirth classes intended to prepare you to labor without an epidural. You can still decide you want one in labor, but epidurals inhibit mobility (see previous bullet) and slow labor, and you’ll learn strategies to help you manage without one.
    • Hire a doula. A doula will have ideas to help you progress in labor and can also keep up your and your partner’s spirits if you experience self-doubt or negativity from medical staff.
    • Decline a routine IV and request that nurses periodically listen to the fetal heart rate (intermittent auscultation) in lieu of continuous fetal monitoring. IVs and continuous fetal monitoring inhibit mobility, and mobility works in your favor. You are on solid ground in doing this. the American College of Obstetricians and Gynecologists guidelines on fetal monitoring in labor support periodic listening in the absence of complications,1 and a systematic review concluded that the evidence does not support routine IVs.8
    • Expect a longer than average labor. Impatience is your enemy, especially with a bigger baby. Better to be pleasantly surprised if labor doesn’t take as long as you anticipated.
    • If IV oxytocin is needed to strengthen contractions, give it time to work. See next bullet.
    • Decline a cesarean or instrumental vaginal delivery based solely on exceeding a preset time limit. That decision should be based on an evaluation of how well you and your baby are tolerating labor, what’s been tried to improve labor or pushing progress, and what progress you’ve made.
    • Push in a position other than on your back or semi-reclining. Side-lying, hands-and-knees, and other non-supine positions allow your pelvis to expand to accommodate the baby,18 and upright positions put gravity in your favor.
    • Plan to deliver on all fours or be prepared to shift to all fours if the shoulders hang up. This can help avert a shoulder dystocia or release the baby’s shoulders should one occur.5, 10 In many cases, you can shift to all fours even with an epidural with assistance and spotters.

      References

      1. ACOG. Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. ACOG Practice Bulletin No 106 2009.
      2. ACOG. Macrosomia: ACOG Practice Bulletin, Number 216. Obstet Gynecol 2020;135(1):e18-e35.
      3. Blackwell SC, Refuerzo J, Chadha R, et al. Overestimation of fetal weight by ultrasound: does it influence the likelihood of cesarean delivery for labor arrest? Am J Obstet Gynecol 2009;200(3):340 e1-3.
      4. Boulvain M, Thornton JG. Induction of labour at or near term for suspected fetal macrosomia. Cochrane Database Syst Rev 2023;3(3):CD000938.
      5. Bruner JP, Drummond SB, Meenan AL, et al. All-fours maneuver for reducing shoulder dystocia during labor. J Reprod Med 1998;43(5):439-43.
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      18. Reitter A, Daviss BA, Bisits A, et al. Does pregnancy and/or shifting positions create more room in a woman’s pelvis? Am J Obstet Gynecol 2014;211(6):662 e1-9.
      19. Sadeh-Mestechkin D, Walfisch A, Shachar R, et al. Suspected macrosomia? Better not tell. Arch Gynecol Obstet 2008;278(3):225-30.
      20. Sanchez-Ramos L, Bernstein S, Kaunitz AM. Expectant management versus labor induction for suspected fetal macrosomia: a systematic review. Obstet Gynecol 2002;100(5 Pt 1):997-1002.
      21. Scifres CM, Feghali M, Dumont T, et al. Large-for-Gestational-Age Ultrasound Diagnosis and Risk for Cesarean Delivery in Women With Gestational Diabetes Mellitus. Obstet Gynecol 2015;126(5):978-86.
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      23. Vendittelli F, Riviere O, Neveu B, et al. Does induction of labor for constitutionally large-for-gestational-age fetuses identified in utero reduce maternal morbidity? BMC Pregnancy Childbirth 2014;14:156.
      24. Vitner D, Bleicher I, Kadour-Peero E, et al. Does prenatal identification of fetal macrosomia change management and outcome? Arch Gynecol Obstet 2019;299(3):635-44.
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