Similarly, evidence for the secondhand mattress threat seemed inconclusive. The concern appeared to stem from a 1997 study that found an increased risk of death from SIDS in infants who slept on used mattresses. A follow-up study, published in 2002, found a “valid statistical association” between hand-me-down mattresses and SIDS, but cautioned that there wasn’t enough evidence to “judge whether this relation is cause and effect.”

The iodized salt was an easier call. Lack of dietary iodine can bring on cretinism, a condition that causes stunted physical and mental development and which is still a significant problem in the developing world. In the U.S., however, it’s extremely rare, particularly since most prenatal vitamins contain iodine.

It’s easy to feel that the effect of any action we do take will be pretty much zilch.

Armed with what little knowledge I could find, the precautionary principle seemed wise in all three cases. Why not simply avoid X-ray scanners, eat iodized salt and buy a new mattress? Easy enough. After all, when the potential risks are high and the effort is minimal, why not take action? Particularly when potential risks resonate on a personal level.

But therein lies the problem when it comes to climate change: Often risks don’t resonate personally and we’re being asked to make dramatic lifestyle changes. On top of that, it’s easy to feel that the effect of any action we do take will be pretty much zilch. I can reduce my carbon emissions; but unless everyone else in the U.S. and China does too, there’s little point.

With pregnancy, I’ve got a little more control. So I’ve bought a container of iodized salt, which I will use to season the food I eat while trying to decide what to do about the crib mattress. I’m on doctor-ordered travel restriction now, which keeps me out of airports. And also, conveniently, helps me to reduce my carbon emissions. View Ensia homepage

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