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Hi! Flintstone's chewable vitamins with iron contain iron and should be available in your local drug store on on line. However, in most cases iron supplementation is not necessary in a menstruating teenager unless she is having unusually heavy bleeding. You can have her physician do a simple blood test to see if she is in danger of becoming anemic if you are concerned. That said, there's little downside to your providing her a multivitamin with iron. Just watch for constipation as that can be a problem when taking medications containing iron.
If your daughter is soaking a maxi pad every 1-2 hours or more her bleeding might be greater than expected and you should discuss that with her physician. Most teens will need to change a pad every 3 hours or so on days with heavy flow (usually the first 2-3 days) with the flow tapering after another few days.
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