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How I Would Counsel a Woman with a Suspected Large Baby


Guest post by an anonymous OB-GYN 



The prompt:

Suppose that tomorrow you were faced with a woman in a similar situation, and an estimated fetal weight of 10 pounds. Would you offer her an elective C-section? Why or why not? How would you counsel her about the risks? Could you do that without mentioning the risk of death? In what way would that be different than playing the “dead baby card?” Please tell me the specific language that you would use as a doctor. Mother has diet controlled gestational diabetes and otherwise uncomplicated pregnancy.


My first response is that I want more information. Was this her first pregnancy? If not what were the weights of her previous newborns?  How much did she and her husband weigh at birth? Where did the estimated fetal weight come from?  If, as I suspect, it is simply the result of a term US, then I would be inclined to ignore it entirely.

The estimated fetal weights derived from ultrasound are routinely incorrect by a factor of 10% across the board and those errors are higher in term mothers with excessive weight gain and much higher in mothers with BMI greater than 25.  At forty weeks gestation, that translates to over 2 pounds in an average size fetus and over three pounds in a larger fetus, i.e.: an 8 pound fetus is likely to be estimated as a ten pounder while a 9 pound fetus risks being estimated at 11 1/2 pounds or even twelve pounds. The larger the fetus, the greater the error.

How have the fundal heights been? We religiously collect this data during prenatal visits for a reason. It has better predictive value than a third trimester US. Has the growth curve according to fundal height been steady or has it accelerated in the third trimester?

How was gestational diabetes diagnosed? How well have her blood sugars been controlled? How much weight has she gained?

How was her gestational age (GA) determined?  Did she have regular menses prior to conceiving? What is the length of those cycles? Does she know without question when her last normal menstrual period began? Did she have any bleeding following her LNMP?

Did she have an early US that confirmed her gestational age?  Was that US abdominal or vaginal. Was her GA determined by an US at any point and if so when? Was that US done by an obstetrician, midwife, or US technician with experience in obstetrical ultrasound?

All of this information should be factored in to properly counsel a woman in this situation.



How would I counsel her without that information?

There is always a possibility that you could have difficulty delivering your baby’s shoulders, which are generally the widest part of the baby to get through your pelvis. That is true with every woman and every baby. We refer to this as a shoulder dystocia.

The risk of a shoulder dystocia is around 1% with babies less than 4000 grams but increases to 5% in babies greater than 4000 grams and higher as weights increase. Most women will not experience a shoulder dystocia even with babies greater than 5000 grams. In women who do experience shoulder dystocias most of those infants are delivered without incidence. Between 5 and 15 % of infants experiencing shoulder dystocia may have a brachial plexus palsy, which is nerve damage that limits mobility of the affected arm.  Ninety percent of those resolve without treatment within 12 months.

The single most common risk factor for shoulder dystocia is the use of vacuum extractors or obstetrical forceps to facilitate delivery.  Other risk factors include: known abnormal pelvic anatomy, poorly controlled gestational diabetes, post-dates pregnancy, previous shoulder dystocia, and short maternal stature.

However, most cases of shoulder dystocia occur in normal weight infants and are unanticipated. Because of this, identifying risk factors has not been shown to have any clinical usefulness.

No evidence exists to support induction in mothers who have gestational diabetes and suspected fetal macrosomia. Induction has been shown to increase rates of cesarean delivery, increase rates of newborn respiratory distress, but has not been shown to decrease rates of shoulder dystocia, or to have any impact on the risk of maternal or neonatal injury.

Elective cesarean delivery likewise is not recommended in cases of suspected fetal macrosomia.  It is estimated that 2,345 cesarean deliveries would be required to prevent one case of permanent brachial plexus injury.  That number may be somewhat smaller in women with both gestational diabetes and suspected fetal macrosomia but there remains no evidence that elective cesarean produces better maternal or neonatal outcomes.

If we were to encounter a shoulder dystocia during your delivery then there are a number of maneuvers that might be employed to complete the delivery. We might ask you top change positions, squat or get on your hands and knees. We might put some pressure above your pubic bone to attempt to dislodge your baby’s shoulder.  We might attempt to rotate the baby’s shoulder manually to dislodge it and to deliver one of the baby’s arms to reduce the thoracic diameter. In severe cases we may intentionally break the baby’s clavicle to reduce the bi-thoracic diameter. This will generally heal without difficulty.  In extremely rare and severe cases we must make more room to get the baby safely through the pelvis. That is best done by injecting local anesthesia into your pubic mons and using a scalpel to cut through the cartilage holding the two halves of the pubic bone together thus allowing the bony pelvis to expand.  This will normally heal without difficulty but may require a temporary brace to facilitate walking until healed.

There is a large body of data that suggests the mother and baby have a higher risk of post natal complications from a cesarean including maternal hemorrhage, hysterectomy, post operative and nosocomial infection, increased difficulties with bonding, post partum depression, and breastfeeding - all of which carry there own sets of future complications,  increased risks of maternal death both with the index pregnancy and more so with future pregnancies, bowel obstruction, placenta previa, placental accreta, vasa previa, and uterine rupture with subsequent pregnancies.

Babies have a higher risk of respiratory difficulties not only in the immediate post operative period but well into adulthood. They have increased rates of asthma, and recently recognized: increased rates of bronchiolitis (birth to 24 months for elective C/S) and pneumonia (12 to 24 months “emergent C/S”), and a huge array of cesarean complications that have been widely reported.

There is no evidence that offering someone a trial of labor produces worse outcomes.



And in answer to the additional question:


“What do you all think about the fact that the woman involved wasn’t counseled about the possibility of a large baby having a possibly difficult delivery and the option of a C-section?”

Every woman who has ever gone into labor since the beginning of time has “the possibility of a large baby (sic) having a possibly difficult delivery…”  Every woman who delivers in the United States has the option of a C-section – but there is not one shred of evidence that that C-section improves her outcome or her baby’s outcome. For the 10,000th time – first do no harm. If you can’t demonstrate with a reasonable degree of significance that doing an intervention actually improves outcomes then you should not be doing it.





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  • Response
    In this retrospective study, there were 27 hysterectomies in 46,766 cesarean deliveries, and 376 hysterectomies in 2,292,420 vaginal deliveries. That is the same as 0.6 per thousand cesareans, and 0.2 per thousand vaginal deliveries. The adjusted odds ratio of any hysterectomy is 3.2 higher odds for cesarean than vaginal delivery. So, ...

Reader Comments (57)

When articles like this talk about the error in ultrasound measurement, the error usually seems to be applied in one direction...estimate a 9lber, actually 8lber. But in reality the error could go either way, right? So an estimated 9lber could actually be a 10lber. So the error issue can't support either the "do nothing" or the "get that baby out" camp, right?

November 20, 2011 | Unregistered CommenterLiz Chalmers

"So the error issue can't support either the "do nothing" or the "get that baby out" camp, right?"

I am personally in the camp of not creating a false dilemma by trying to simplify something like this into black-and-white. Understanding the effectiveness and application of measurements is essential to both clinical and patient decision making.

November 20, 2011 | Registered CommenterJill

The above sounds like great evidence based advice. Wish all care providers provided the same. I did a series on birth weight a while back based on WA state's birth certificate data. I'm not sure if the data is terribly meaningful, but it is a bit interesting all the same

November 20, 2011 | Unregistered CommenterLaura

What my OB told me was he estimated my sons weight at 8lbs, he was born two days later at 9lbs 7ozs. During the exam I was told that I had low fluid levels and my son was breech and I had preeclampsia and I needed a c-sec, a transversion wouldn't work because he was large.
A day before the scheduled c-sec I went into spontaneous labor, I was at 4cm when I got to the hospital and I was in the OR within 30mins of getting there.
During the six week postpartum check up I was told the hospital does not allow VBACs and I would have to travel three hours away to have one. No mention of risks.

November 20, 2011 | Unregistered Commenterlaura

Excellent. I shouldn't have read it before I tried to write my own, because it covered all the points I could have dreamed of discussing.

November 20, 2011 | Unregistered CommenterMomTFH

MomTFH, just copy and e-mail the same post as above and see if I notice that you're a cheater.

November 20, 2011 | Registered CommenterJill

This totally hits home for me. With my first baby being 10lbs 11.5oz and a CS, second baby a VBAC weighing 9lb 8oz, I dont look forward to the stigma that will put on me when I have my next child. Even knowing I had a successful VBAC last time, it seems like I will always have an uphill battle for vaginal birth. I have never had GD, and with my most recent pregnancy I measured/weighed perfectly all the way through. Doesnt seem to matter how perfect the pregnancy is, if an OB is determined to see something they will see it. I am so thankful I did find one who would work with me, and my daughter's birth was awesome. I guess I just always figured that after I had a VBAC once it would be easy to do the next time, but I am starting to realize that may not be the case.

November 20, 2011 | Unregistered CommenterLilRedMommy

You didn't include the offer for an elective C-section. If the baby dies or is disabled, you lose! Please pay $144 million.

The entire point of my original post about the case is that the counseling you would like to offer doesn't meet the requirements of the court.
Moreover, you deliberately left out the risk of death and disability that accompanies severe shoulder dystocia. You didn't even meet the ethical and legal requirements for informed consent, let alone the additional requirement for offering an elective C-section.

You slanted your information to reflect your personal bias against C-sections instead of offering unbiased information.

Try again.

November 20, 2011 | Unregistered CommenterAmy Tuteur, MD

Oh my god a real ob/gyn. Where have they all gone? Great answers great facts !

November 20, 2011 | Unregistered CommenterMarchc

I'm sorry Dr. Tuteur, but as usual, your comments are not logically consistent.

This is unbiased information, because it presents real absolute risk, with evidence based statistics and recommendations, numbers needed to treat, and descriptions of possible interventions.

You are suggesting that, instead, an elective cesarean that is not evidence based should be offered because of a biased fear of a large malpractice settlement.

In that case, wouldn't informed consent have to include that detail? There is a diminishingly small chance there would be a shoulder dystocia, much less one with a truly poor outcome, and elective cesarean is not recommended to avoid this, but I'm afraid of you suing me... so whaddya think?

November 20, 2011 | Unregistered CommenterMomTFH
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