Pregnancy does wierd things to your body. Some women, not all tho, have cravings for non food items like dirt, ice, soap, ect. Ect. I believe the term is called PICA? Not 100% positive if thats what its called. Usually it means that you are lacking something like iron or could be something else. Its completly normal, just dont indulge in the detergent :)
If you want to eat it, then you may have pica. Talk to your doctor about this right away, because your body is missing nutrients. Take care, and I hope you don't give in to your cravings.
Definitely let your doctor know this. Pica can be because of chemical imbalance as well as some issues with nutrition. I would talk to your doctor because either of those require doctor supervision to rectify. Don't eat it!! Talk to your doctor so they can help you. good luck