Busting the fear of the big baby
The medical term for big baby is macrosomia, literally large body.
A baby is considered macrosomic if they are 4kg (8Ib 13oz) or larger.
Around 1.8% of Australia babies being born are considered macrosomic
While a bigger baby may increase certain birth complications it does not necessarily mean a high risk birth
There are a couple of things I’d like to talk about here:
The only way to know a baby’s actual size is to weigh and measure after birth. Tools used by our caregivers during pregnancy are good ways to “track “general growth but the accuracy of measurements become less and less as the pregnancy progresses.
By the third trimester an ultrasound weight prediction can vary from the actual birth weight by 10-15%. These methods provide an estimate or educated guess and we must remember that there is room for error in this. There is NO accurate way of diagnosing a macrosomic baby prior to birth.
An evidence-based article on induction and c-sections for big babies states:
“Although only one in ten babies is born large, researchers found that two out of three American mothers had an ultrasound at the end of pregnancy to determine the baby’s size, and one out of three mothers in the entire study were told that their babies were too big. In the end, the average birth weight of these suspected “big babies” was only 7 lbs., 13 oz. (Declercq, Sakala et al. 2013).
Of the mothers who were told that their baby was getting big, two out of three said their care provider discussed inducing labor because of the suspected big baby, and one out of three said their care provider talked about planning a Cesarean because of the big baby.”
In the study reference above, the most concerning part of the story was that some of the women (2:5) felt the discussion was framed as if there were no other options other than c-section for their suspected big baby.
Is this approach evidence based?
Having a big baby does not necessarily mean you have high risk birth but it can increase certain birth complications. The sorts of complications that mothers may be worried about include:
their baby’s head not fitting through their pelvis (a condition known as cephalopelvic disproportion (CPD))
baby’s shoulders getting stuck in mama’s pelvis (shoulder dystocia) happens to around 7-15% of big babies but most cases can be handled by a skilled obstetrician without any harmful consequences for the baby, refer to this article for more information on this issue)
unplanned caesarean
perineal tears (research associates increased rates of assisted delivery use of episiotomies, vacuum and forceps as likely contributing factor to an increase in severe tears)
postpartum haemorrhage (it is not clear from research if the higher rates are from baby itself or from the inductions and caeserans that care providers often recommend for suspected big baby as both procedures can increase risk of postpartum haemorrhage)
stillbirth (there is very little research on this topic)
There are many things that can be done to reduce the risks of complications and this warrants a discussion with your caregiver. Avoiding unnecessary inductions, assisted births and remaining upright and mobile during labour and birth are some examples. It also important to point out that it is nearly impossible to diagnose CPD or predict the risk of shoulder dystocia prior to birth.
Scheduling an induction or c-section (without evidence to support it) is not necessarily going to improve mamas and baby’s health outcomes. A suspected big baby is not enough evidence to support this as routine management. There are many women who have birthed large babies vaginally without trauma and complications, and yes there are risks with larger babies but c-sections and inductions also have risks – weighing up the benefit and risk of spontaneous labour vs. scheduled birth (e.g induction or c-section) and making an informed choice about which way you want to go is critical determinant for a positive birth experience.
When weighing up your decisions, it is also important to consider these points:
There is a lack of evidence to support the recommendation that elective caesareans for all suspected big babies have benefits that outweigh potential risks of a vaginal birth. While a vaginal birth carries risks, c-section surgery does too, with harms to mother, baby and children born in future pregnancies.
There is evidence to suggest that when women and their caregivers suspect macrosomic babies, these women tend to have higher rates of interventions when compared to women who had unexpected macrosomic babies.
The hypnobirthing practitioner in me questions the role of fear in this? Does a suspected big baby lead a caregiver to manage labour in a way that increases induction and caeseran rates and does telling a mother she ‘may have a big baby’ undermine her confidence in being able to physiologically birth her baby?
As this evidence-based article quotes:
“When a big baby is suspected, pregnant people are more likely to experience a change in how their care providers see and manage labor and birth. This leads to a higher Cesarean rate and a higher rate of women inaccurately being told that labor is taking too long or the baby does not “fit.” In fact, research has consistently shown that the care provider’s perception that a baby is big can be more harmful than an actual big baby by itself.”
If you are worried about having a big baby, consider these suggestions (bear in mind there are some things in pregnancy and birth that are out of our control):
Maintain a healthy, wholefoods diet.
Remain active to keep blood sugar at healthy levels, regularly walk or take pre-natal exercise classes.
Choose a provider that does not use routine growth scans in normal, low risk, healthy pregnancies (i.e. there are no risk factors present in your pregnancy)
Remember that the tools made available to caregivers cannot accurately diagnose a big baby
Choose a provider where scheduled inductions and births are an exception (they have been medically indicated) rather than the norm to their practice.
Learn positive mindset techniques such as Hypnobirthing to help release fear and promote a more relaxed response to your pregnancy, labour and birth.
Do daily exercises and positioning that optimises baby’s position and prepares your body for birth.
During labour and birth preference movement and upright positions.