[christophilus]

Most likely, pregnant women who aren’t working can rest more. They can sit when the want, go to the restroom when the want, etc. These are things that take a cumulative toll when working / add a cumulative benefit when not.

[bananaface]

It sounds appealing as an explanation, but so does the general stress argument. I'm skeptical of concrete explanations in general.

[emn13]

The stress of fearing a pandemic is perhaps quite different from the everyday stresses of work. We may find them both severe - even the fear much worse; but it's still conceivable the everyday stresses are worse specifically to the extent they influence birth weight. Perhaps everyday stress is more immediate; perhaps it's more physical; or perhaps it's more social - or perhaps we're grasping at straws and it's something else entirely.

In any case; just because a pandemic is stressful doesn't necessarily mean that stress that matters here isn't lower. All those various strains don't affect us in the same way.

[bananaface]

It could also be that they are sleeping more, which people will try and shoehorn into: "that's a form of stress!" Stress is a buzzword, I'm wary of manhandling the theory too much as counterpoints come up, especially if it involves playing with semantics.

[emn13]

Exactly; stress isn't one clearly defined thing, and the forms do matter: therefore the focus on overall stress isn't that useful.

[bananaface]

It's worse than that: "it's stress" is a lexical tautology. By definition anything that causes a miscarriage was a stressor.