Many moms-to-be feel like a beached whale during the third trimester — so when your doctor tells you that she suspects you are going to have a “large” baby, it’s normal to start wondering about the logistics of getting baby from point A (your cozy but crowded womb) to point B (the outside world). A new study looked at the labor and delivery outcomes of almost 2,000 new mothers surveyed nationally and found that while over 30% of women were told by their doctor or medical professional that their babies were getting “quite large,” less than 10% actually ended up delivering large babies (defined as more than 8 pounds and 13 ounces). The new study also highlighted how even the suspicion of having a large baby influenced the course of labor and delivery.
Four out of five mothers who were warned that their baby might be defined as large ended up delivering babies of a normal size, with the research showing that the women who were suspected to be carrying large babies also had increased odds of epidural use, medically-induced labor, and attempted self-induced labor. They were more likely to ask for and plan C-sections as well. The discrepancy between the size babies were assumed to be and the size they actually were comes from the (literature-supported) fact that birth weight prediction tools are, in the words of a physician who helped develop the most recent set of guidelines for OBGYNs “so poor.”
While less than 8% of babies born in the U.S. meet the medical definition of a large baby, our country has a one in three C-section rate, and some experts now believe part of that high rate could be attributed to the incorrect assumptions about a baby’s large size — on both the side of the pregnant woman and her doctor. The study, according to one of its authors, demonstrates how simply telling a mom-to-be that her baby might be large “has a profound effect, and contributes to undermining women’s confidence they can deliver the baby.”
Although many women deliver healthy “large” babies without interventions, the knowledge of a suspected larger baby might make a mom-to-be doubtful of her own birthing ability and cause her to needlessly worry. Doctors also might be more likely to offer a C-section to the pregnant patient and possibly try to pressure her in these situations. There are some medical risks and complications (as well as the experience of potentially birthing a giant baby through the birth canal) associated with “large” babies and they should be carefully considered as well, but this study shows how influential the simple power of suggestion can be — and how inaccurate our current measurement methods are.