Pica! Wtf?

I am 30 weeks now and have had Pica cravings for the last few weeks. I crave sand, dirt, chalk, pool water, salt water and last night absentmindedly nibbled on some charcoal whilst tending the wood heater! I surmise that I might be deficient in some mineral but apart from keeping up with my antenatal vitamins and liquid iron, alternating with magnesium I am stumped. It is really bad- when I watch TV show where there is digging in dirt my cravings are really strong and I keep wanting to go swimming for the chlorine! Anyone experienced this or is it just me being freaky?

I think that rather than trying to guess what you might be deficient in the best option would be too ask your Dr for a full blood test ASAP.
Pica can be caused by worms so maybe get a stool sample too.

I think if it was worms I would have other symptoms (from what I remember as a child anyway!) It looks like most cases are due to iron deficiency which rings true (I don't eat red meat and iron needs have just gone up!).