The “Big Baby” Issue – Answers by Henci Goer

Another enlightening answer by obstetrical expert Henci Goer from last week’s Q&A session on the Lamaze Facebook page. For more answers from Henci, visit her forum on the Lamaze website. 

Q

More and more we hear about “big baby” as a justification for induction or c-section. I was one of those mothers myself before becoming more educated in my options. However, my second baby was 11lbs. at birth. What do you feel are the things to consider when you may be genetically prone to growing a “big baby”? Do you feel the position of the baby is more important than the baby’s size when it comes to birthing a “big baby”?

A

Unfavorable position is clearly the bigger problem because it affects babies of all sizes, but while, logically, size has to be an issue as well, there are no neat cut-off points. Here is what the research tells us about big babies that can inform strategies for maximizing safe, healthy birth:

• High BMI women tend to have bigger babies. Take home message: losing weight sensibly before pregnancy might be beneficial.
• Eating a healthy diet and exercising regularly optimizes sugar metabolism. Take home message: this, too, could optimize fetal weight.
• When obstetricians wrongly believe (based on sonographic weight estimates) that the baby will be big, women are much more likely to have a cesarean than when the baby actually is big, but the doctor didn’t suspect it and vice versa. Take home message: I’m not sure that refusing a weight estimate will help because, as this makes clear, it is a matter of what the obstetrician believes. I think it would be more useful for women to explore early on how her care provider feels about women’s ability to birth bigger babies and how he or she handles that situation. Specifically . . .
• Inducing labor for “suspected macrosomia (baby predicted to weigh 8 lb 13 oz or more)” increases cesarean surgery rates without reducing incidence of shoulder dystocia (the head is born but the shoulders hang up behind the pubic bone) or delivery injury rates. Take home message: await spontaneous labor onset.
• Planning cesarean surgery exposes women to the serious potential harms of major surgery. The best way of determining whether the baby is too big to come out is to go through labor and see. Take home message: don’t plan surgery.
• Labor with a big baby is likely to take longer, at least partly because the cervix may have to open further to pass a bigger head. (The “10 cm diameter” definition of full dilation is actually not really 10 cm. For the last few cm of dilation, clinicians measure, not the diameter, but how much rim is left. This means that the true diameter might be a cm or two bigger.) Take home message: find a care provider willing to be patient with a longer labor and who has no preset time limits for making progress.
• Epidurals, confining women to bed, pushing while reclining or semi-reclining can all impede progress. Take home message: choose a place of birth that allows freedom of movement and plan alternative means of coping with labor pain so as to bypass or delay an epidural. Also, hire a doula. Doulas can help with strategies to promote good progress and increase comfort as well as with emotional support should labor progress slowly.
• The best “first response” to shoulder dystocia is assuming a hands-and-knees position: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=9610468. Take home message: either plan to give birth in this position or have a plan with the care provider to turn to this position should the shoulders hang up. (With today’s modern “light” epidurals, it should be possible to turn to all fours with assistance even with an epidural in place.)