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 You may have been advised that it would be best for you and your baby if you are induced early? or perhaps an elective C-Section has been advised.

You might have been told that you baby is much more likely to get stuck (also known as "shoulder dystocia"), but does the research agree?  

Actually the vast majority of research into Macrosomic babies indicates that elective C-Section and induction for just a suspected large baby is a bad idea, deeming it unneccessary, needlessly expensive and not effective at preventing birth trauma to the mother or baby.

When looking at induction the research is in fact even more scathing, with many suggesting that early inductions only serve to raise caesarean section rates without altering outcomes for the mums or babies.

Finally, just suspecting a macrosomic baby can lead to problems, with one study (see 7 below) indicating that the risk of cesarean section was substantially higher (52 versus 30 percent) in pregnancies in which macrosomia was suspected, even after controlling for birth weight and other confounding variables. More importantly, the difference in the cesarean section rate was attributable to a greater proportion of failed inductions for macrosomia in the group in which it was suspected.

The following is a short summary of Positive "Big Baby" research.

Please note: this website is a work in practice - if you known of any research that we haven't included then please do tell us by emailing editor@bigbaby.org.uk

Let's start by looking at the Cochrane Review looking at "Induction of labour for suspected macrosomia", April 1998. The summary of the review is as follows. Important points have been highlighted:

"Babies who are very large (macrosomic - over 4500 g) can sometimes have difficult and, occasionally, traumatic births. One suggestion to try to reduce this trauma and to reduce operative births has been to induce labour before the baby grows too big. However, the estimation of the baby's weight in utero is difficult and not very accurate. Clinical estimations are based on feeling the uterus and measuring the height of the fundus of the uterus, and both are subject to considerable variation. Ultrasound scanning is also not accurate. Induction, if undertaken too early, can lead to babies being born prematurely and with immature organs. The review of trials, assessing induction of women when it was suspected that their baby was above 4 kg, found three trials involving 372 women, none of them with diabetes. There was no evidence of any benefit in terms of caesarean section or instrumental births, or in outcomes for the baby. However, these studies were too small to be sure of the outcomes. Further research is in progress."

The results section of the Cochrane Review also states:

"Perinatal morbidity was not statistically different between groups (shoulder dystocia)."



2) In the Archives of Gynecology & Obstetrics, September 2008. Sadeh-Mestechkin, Walfisch, Shachar, Shoham-Vardi, Vardi & Hallak, in their study entitled "Suspected macrosomia? Better not tell" noted that:

"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."


3) In 1994, in The Chinese Medical Journal, Yan, Chang & Yin, in their article "Elective cesarean section for macrosomia?" studying the births of 207 macrosomic babies concluded that:
 
"Elective Cesarean section on macrosomic infants to prevent dystocia is not recommended because most of them can be delivered vaginally."



4) In 2000, in the European Journal of Obstetrics, Gynecology & Reproductive Biology, Mocanu, Greene, Byrne & Turner studied the births of 828 macrosomic babies born over a 5yr period in their report entitled "Obstetric and neonatal outcome of babies weighing more than 4.5 kg: an analysis by parity" they concluded that:

"The poor antenatal predictability of macrosomia, the high rate of vaginal delivery and the low incidence of shoulder dystocia would not support the use of elective caesarean section for delivery of the macrosomic infant either in primigravidae * or multigravidae."

* Editor's Note: Primigravidae = First Time Mother, Multigravidae = Second or More time mother.


5) In april 1995 in Obstetric Gynecology in their research "The outcome of macrosomic infants weighing at least 4500 grams: Los Angeles County + University of Southern California experience" looking at 227 births of macrosomic babies, Lipscomb, Gregory & Shaw noted that:

"Vaginal delivery is a reasonable alternative to elective cesarean for infants with estimated birth weights of at least 4500 g, and a trial of labor can be offered.".


6) In 2006 in the American Journal of Obstetrics & Gynecology, Chauhan, Grobman, Gherman, Chauhan, Chang, Magann and Hendrix reviewed the evidence for performing an elective ceasarean or an induction for suspected macrosomia, in their article "Suspicion and treatment of the macrosomic fetus: a review." they noted that:

"Due to the inaccuracies, among uncomplicated pregnancies suspicion of macrosomia is not an indication for induction or for primary cesarean delivery."


7) In 1996, Rouse, Owen, Goldenberg, Cliver, in "The effectiveness and costs of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound" published in JAMA 1996.  estimated that

"to prevent one case of permanent brachial plexus injury, 3,700 women with an estimated fetal weight of 4,500 g would need to have an elective cesarean section for suspected macrosomia at a cost of $8.7 million per case prevented."