Hello and welcome to more or less on the BBC World Service.

This week we're taking a statistical look at the various pieces of advice that are given

to expectant mothers and they're usually pro-abissions, things you're not allowed to do during

your pregnancy.

Just to get a flavour, I asked some of the women sitting around me in the office.

I was told I shouldn't eat prawns but I decided I was too short without prawns so I ate

prawns.

I wouldn't have eaten unpasteurised cheese.

Well, cheese lover, so not to be able to eat la brie was something I was upset about.

A friend of mine was so upset at missing soft cheeses she actually brought them into the

labour ward with her when she gave birth so she could eat brie as soon as she'd given birth.

The advice was not to drink caffeine, no caffeine, no booze, not a big deal.

But why aren't pregnant women supposed to consume various things?

What's the evidence behind this advice?

My name is Emily Astor, I am a professor of economics at Brown University.

Emily started asking herself those questions when she became pregnant.

She would go to the doctor who would tell her what she should and shouldn't be doing.

Then when I had the follow up question like, okay, can you tell me why you're recommending that?

And then it was sort of like, well, that's what we do, that's the rule.

As the statistical nerd that she was, she wouldn't let that lie as an answer.

So my day job is a health economist and so I spend a lot of time reading and writing research papers

about how people make decisions about their health.

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