Understanding the Evidence: Induction for Suspected Large Babies
I truly care about supporting families in the Denver metro area as they navigate the beautiful journey of pregnancy, labor, and parenthood. I understand how overwhelming it can be to sift through all the information out there, especially when you're trying to make the best decisions for your growing family. That’s why I’ve gathered the latest research and evidence-based insights to help you feel empowered and confident in your choices. Your journey matters, and I'm here to help you every step of the way!
Today’s topic: What does it mean if my provider tells me that my baby is "measuring big”?
Why might my provider be offering me an induction?
Before diving into the evidence, let’s explore some common reasons your OB or midwife might recommend early induction (before 40 weeks) if they suspect your baby is larger than average.
Your suspected large baby may potentially need to be born by cesarean section.
There is a a greater likelihood of more severe perineal tearing during birth.
Potential complications for the baby immediately after birth.
The risk of the baby’s shoulders getting stuck during delivery (shoulder dystocia).
The possibility of needing assistance with forceps or a vacuum during delivery.
So, what does the research says about these concerns and whether early induction is beneficial in these cases?
“If your baby is too big, then they might need to be born by c-section”
An early induction might be encouraged in order to decrease your likelihood of a cesarean birth, which carries its own set of risks and complications. However, recent research suggests that there is no difference in cesarean rates when families choose an early induction or wait for spontaneous labor.
In fact, several studies suggest that cesarean rates tripled when a care provider “suspected” a big baby, compared to not knowing if the baby was going to be big. This often happens because providers are more inclined to recommend a cesarean when they suspect the baby is larger than expected or believe that labor is progressing “too slowly” or that the baby “may not fit” through the birth canal.
Will an early induction decrease my risk of cesarean?
No. Evidence indicates that it does not lower the chances of a cesarean and may actually increase your likelihood of having one.
“Your big baby will cause more severe perineal tearing”
Despite this idea being used as a reason to induce labor, there is not sufficient evidence to conclude that there is a decreased risk of perineal tearing when inducing labor for a large baby. Studies have found conflicting information, and while there could be a small risk of more severe tearing, it may be helpful to compare this risk to other situations that can also increase the risk of tears such as the use of vacuum and/or forceps.
Will an early induction decrease my risk of perineal tears?
No. There is not enough evidence to suggest that the likelihood of perineal tears will decrease.
“Your big baby is at risk for more complications after birth”
Another concern with larger babies is the potential for complications immediately after birth. However, research shows that inducing labor early for a suspected large baby doesn’t reduce the need for NICU stays. However, a recent study found that babies that were born after an early induction (37-38 weeks) were more likely to have jaundice and require treatment (which can mean a longer hospital stay).
Overall, there was little to no impact on APGAR scores, meaning your baby’s health at birth is typically unaffected whether your labor was induced or started on its own.
Will an induction reduce complications for my baby after birth?
No. Recent research shows no decrease in APGAR scores, no increase in NICU stays, but does show an increase in babies needing treatment for jaundice.
“Your big baby has a higher risk for shoulder dystocia”
It’s true that larger babies have a higher risk of experiencing shoulder dystocia during birth. When the findings of several studies are combined, it is found that shoulder dystocia happened in 6% of babies who weighed more than 8lbs 13oz vs .6% of of those who were not that big. When babies weighed more than 9lbs 15oz, 14% experienced shoulder dystocia.
However, it is very important to note that most of these cases are handled by the care provider without any harmful consequences for the baby (permanent nerve injuries due to stuck shoulders happen in 1 out of every 555 babies who weigh between 8 lbs. 13 oz. and 9 lbs., 15 oz., and 1 out of every 175 babies who weigh 9 lbs., 15 oz. or greater).
It is equally important to note that, while big babies are at higher risk for experiencing shoulder dystocia, at least half of all cases of shoulder dystocia happen in smaller or normal sized babies.
Summary. While a bigger baby has a higher risk of shoulder dystocia(6-14%), having a smaller or average-sized baby does not eliminate the risk of shoulder dystocia. Most cases are quickly resolved by your provider.
“You are more likely to need the use of vacuum or forceps delivery because you have a big baby”
Instrumental deliveries, such as those using vacuum or forceps, carry certain risks, including a higher likelihood of perineal tears, blood clots, and incontinence. While early induction for a suspected larger baby might initially appear to be a way to avoid the use of these tools during a vaginal birth, recent evidence indicates that early induction does not reduce the likelihood of requiring instrumental assistance.
Will an induction decrease my risk for the need of vacuum or forceps?
No. The evidence shows no decreased risk.
Other Considerations
When making decisions with your birth team, consider the following:
Ultrasounds predicting baby size are only accurate about 50% of the time, meaning large baby predictions may be wrong in half of the cases.
Ultrasound results are usually anywhere between 15% above or 15% below your baby’s actual weight… and they are only right 50% of the time.
Important Questions to Ask your Provider
What does your induction process involve and what are my other options?
Could we wait another week and monitor how much weight my baby might gain?
Can I have a follow-up ultrasound with another technician to double-check my baby’s estimated size?
How experienced are you and your team in managing shoulder dystocia?
It’s important to collaborate with your birth team to ensure you make the best decisions for your family. Ultimately, the most informed choice you can make will always be the right one for you.
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