Birth outcomes in plus size pregnancy

We clearly have more to learn and understand about birth outcomes in plus size pregnancy.

But one thing is clear. 

Several studies indicate that the differences in birth outcomes experienced in plus size pregnancy may be due as much to provider attitudes and biases as to any intrinsic difference or disadvantage.

I have written at length about this in my book Plus Size Pregnancy: what the evidence really says about higher BMI and birth.

But let’s look at just one example of this.

An example of a study

In a study in Denmark, Ellekjaer et al (2017) looked at the records of 1885 women who gave birth at term to a single, head-down baby at one hospital in Copenhagen.

Among other things, they compared the length of labour and the type of birth that overweight and non-overweight women experienced.

Now, we know that many people say that women with a higher BMI have longer labours. And there is evidence to show that they have a higher chance of being told they need a caesarean.

But remember that these are not objective measures. Measuring the length and progress of labour is notoriously personal and subjective. And caesareans are the result of a clinical decision.

Further concerns

Ellekjaer et al’s (2017) findings echo the concerns of many of those involved in the care of women with a higher BMI. That is, we can see that the reason they are more likely to end up with a caesarean isn’t necessarily because of their body shape, weight, or size, but because of the attitudes of health professionals, the additional tests and interventions they are told they need, and/or the restrictions that are placed upon them by the application of fatphobic and weight biased obstetric guidelines.

As the authors wrote:

“We found that obese women were granted fewer hours of active labour before a caesarean was performed compared with women of normal weight. This could be explained by a possible earlier onset of labour complications within the obese population. However, since there was no difference in the numbers within the different levels of emergency caesareans, this seems unlikely. Alternatively, an increased consciousness amongst healthcare staff concerning the issue of maternal obesity may have had an indirect influence on treatment. A more cautious approach to managing these women might have been unknowingly adopted, resulting in an earlier decision to perform a caesarean delivery.” Ellekjaer et al (2017).

Why we need to explore this further

As these authors explain, other studies have found slightly different things.

“A few previous studies suggested no association between labour progression and increasing BMI.

A British study of 8350 nulliparous women compared labour progression in obese versus non-obese women, observing no significant difference within the first or second stages of labour [8].

Contrary to our findings, a majority of previous studies report an independent effect of BMI on total duration of active labour. These studies specifically identify the duration of the first stage of labour as being increased, further supporting an overall increase in labour duration [9, 10, 11, 13, 14, 15].

A study by Kominiarek et al. included 118,978 nulli- and multiparous women in separate analyses. This study found a significant increase in total duration of labour with increasing BMI among nulliparous women [11]. However, the definition of active labour differed from that of most other studies, as a cervical dilatation of only 1 cm was accepted when defining the onset of labour, thereby including what was considered as the latent phase in the current study.” Ellekjaer et al (2017).

But none of these findings negates the point I made above. Which is that the current approach isn’t helpful to women with a higher BMI. (It’s arguable whether it’s helpful to other women too, but that’s not the topic of this blog post.) It seems very clear that we need to take a closer and more open-minded look at what is happening.

Which is exactly what I’ve done in my Plus Size Pregnancy book.

So I am delighted to see that it is helping women and families to become informed about the issues.

Because it’s very clear that the current approach isn’t evidence-based, effective, or respectful.

Ellekjaer et al (2017) suggest that, “Defining the normal progression of labour for overweight and obese women can help eradicate non-scientific misconceptions about the influence of obesity, resulting in more appropriate treatment of women in this weight group.”

I agree with that to some extent. I think it’s good to understand the different things that can impact someone’s experience of labour and birth. I think it is critical, in this day and age, to become informed before you enter a maternity care system or facility, so that you can make the decisions that are right for you.

But one size never fits all, and that might be the most important thing of all.

I discussed some later studies on the same topic in this blog post:

Ellekjaer KL, Bergholt T and Løkkegaard E (2017). Maternal obesity and its effect on labour duration in nulliparous women: a retrospective observational cohort study. BMC Pregnancy and Childbirth:222. DOI: 10.1186/s12884-017-1413-6

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