Women with higher BMI: it doesn’t have to be complicated!

We have heard much over the past few years about the risks posed to women with higher BMI than average. It’s clear, however, that this focus is problematic in a number of ways. The evidence isn’t clear cut. There is wide individual variation that is missed when we focus on single parameters. There is also much concern about weight stigma and disrespectful care.

Women with higher BMI have variously reported to us that they, “feel distressed after a call from a lifestyle midwife who spouted risks and then lectured me about causing harm to my baby,” are “sick of being patronised when I eat healthily and exercise every day,” and “just want someone to stop making assumptions based on one facet of my health when there is so much more to it than that.”

These quotes are just the tip of the iceberg. We receive many enquires on this topic and we’re unable to reply individually, However, I wrote about a recent study in my Birth Information Update that I think is worth everyone’s attention. It is my hope that writing about this here as well might at least help show that there is more that needs to be taken into account than tired, unevidenced assumptions about size.


A new study…

The study I spotted is a population-based cohort study of characteristics associated with uncomplicated pregnancies in women with obesity. Researchers in Canada set out, “to calculate the rate of an uncomplicated pregnancy (antenatal period) in pregnant women with obesity and to determine the demographic and clinical factors which are associated with such uncomplicated pregnancies. We also set out to determine if the prediction of uncomplicated pregnancy using identified factors is feasible amongst women with obesity.” (Relph et al 2021).

Those of us who already seek to give great care to women with a high BMI without taking a risk-focused approach won’t be surprised to see the results. When I talk to woman-centred practitioners who try hard to not treat people differently because of their size, I hear them express surprise at the idea that having a high BMI in itself leads to more problems. What is also very clear to those of us who are concerned about this issue (and there is some evidence on this as well) is that making assumptions and treating people differently because of how they look can lead to their having worse outcomes.

That means it’s difficult to untangle whether poorer outcomes and higher intervention rates are based just on size and shape, or whether (and to what extent) they are the result of people being treated differently because of their size and shape.

I talk about this more in my 2021 book, In Your Own Time: how western medicine controls the start of labour and why this needs to stop.


So what did they find?

In the case of this study:

“The study demonstrates that over half of women with obesity but no other pre-existing medical or early obstetric complicating factors, proceed through pregnancy without adverse obstetric complication.” (Relph et al 2021).

Importantly, the researchers argue that:

“Care in lower-risk settings can be considered as their outcomes appear similar to those reported for low-risk nulliparous women.” (Relph et al 2021).

Lastly, the research team have a suggestion for future research:

“Further research and predictive tools are needed to inform stratification of women with obesity.” (Relph et al 2021).


Stratify, or individualise?

I don’t know if I’m as convinced about that bit. I’d personally rather see an individualised approach, and there are other statements in the study that I don’t wholly agree with, but that’s often the case. This is a start towards a more woman-centred approach, and it’s always good to see more research exploring the notion that health isn’t based on one parameter.

More on this in In Your Own Time.


As always, if you’d like to be among the first to hear my thoughts on new studies and to get updates about my work, new birth-related research and thinking, make sure you’re subscribed to our free newsletter list, which means you’ll get our monthly Birth Information Update and details of my current projects.
And if you’re a midwife or other birth worker who enjoys unpacking research, seeing what’s behind the headlines and sharing wisdom with like-minded others, come and join Sara and colleagues from all over the world in one of our online courses!

Relph et al (2021). A population-based cohort study of characteristics associated with uncomplicated pregnancies in women with obesity. BMC P&C 21(182).