Preterm labor due to dental problems?

My doctor said something to me today about possibly going into preterm labor if I dont take care of my gums and teeth. Has anyone else ever heard of this?
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I've heard of this but only if you have infections in your mouth... abcess in the gum, infected tooth.... infected gums... basically you need to take good care of your teeth and gums while pregnant so you don't get any mouth bacterial infections..which might go into your blood and...preterm http://jada.ada.org/cgi/content/full/132…
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