Fetal Macrosomia and the "Big Baby" Cesarean Section

One of the commonly documented reasons for cesarean section is for suspected macrosomia, or the "big baby" syndrome.


Yet another study has been published which highlights the chasm between research and practice in modern maternity care:



Sadeh-Mestechkin D, Walfisch A, Shachar R, Shoham-Vardi I, Vardi H, Hallak M. Suspected macrosomia? Better not tell. Arch Gynecol Obstet. 2008 Feb 26; [Epub ahead of print] PMID: 18299867


OBJECTIVE: To evaluate the management policy of delivery in a suspected macrosomic fetus and to describe the outcome of this policy.


STUDY DESIGN: For this prospective observational study we followed the management by reviewing the medical records of 145 women and their infants. The study population included women at term admitted to the obstetrics department with suspected macrosomic infants, as was diagnosed by an obstetrician and/or by fetal sonographic weight estimation of >/=4,000 g. The comparison group (n = 5,943) consisted of all women who gave birth during the data collection period.


RESULTS: Induction of labor and cesarean delivery rates in the macrosomic pregnancies (actual birth weight >4,000 g) of the study group were significantly higher when compared with the macrosomic pregnancies of the comparison group. When comparing the non-macrosomic to the macrosomic pregnancies (actual birth weight 4,000 g) of the study group no significant difference was demonstrated regarding maternal or infant complications. The sensitivity, specificity and positive predictive value of the methods used for detecting macrosomia were 21.6, 98.6 and 43.5%, respectively.


CONCLUSION: Our ability to predict macrosomia is poor. Our management policy of suspected macrosomic pregnancies raises induction of labor and cesarean delivery rates without improving maternal or fetal outcome.


Notice the conclusion: induction and/or cesarean section for suspected fetal macrosomia, or "big babies" does not improve outcomes. This is yet more evidence of a fact already established. Despite the research, late term ultrasounds to check fetal weight are becoming a routine part of modern prenatal care. However, this routine practice carries no benefit and definite drawbacks for both you and your baby.


This means that for the vast majority of mothers told they require an induction or c-section for suspected cephalopelvic disproportion (CPD), or even told that "some women just aren't made for childbirth".


So,the real question comes down to how to avoid falling down the slippery slope from "you're measuring larger than average" to "your baby is huge, you need an induction/c-section (and often both as induction increases the risk of c-section fourfold).


Step 1

Choose your provider well. Ask the tough questions. Nail down the percentage of primary c-section, inductions, episiotomy, etc. Don't take vague estimates for answers.


Step 2

Avoid late term ultrasounds. They can be off by as much as two pounds in either direction and provide little to no true information on whether your baby will actually fit. The only way to know is to labor first.


Step 3

Avoid continuous fetal monitoring. This will limit your movement which is a contributing factor to failure to progress c-sections (another red herring) by restricting your ability to let the baby navigate down the pelvis and use gravity's help.


Step 4

Refuse to have your membranes ruptured. This can contribute to fetal malpositioning that can inhibit the baby from properly navigating below the pelvic bone and presenting the smallest head circumference. This becomes especially important if the baby truly is on the larger side of average.


Step 5

Give birth at home. None of the non evidence-based procedures and interventions are used in homebirths. Anxiety and stress levels are also lower in a place where you feel safe and secure. This is rarely a place swamped with ill strangers, smelling of antiseptic and surrounded by machines that go "ping".