Your mother might be old enough to remember when tampons were made of materials associated with Toxic Shock Syndrome (TSS)....so I can understand why she might be concerned about menstrual cups.
All menstrual cups are approved by the FDA. From my research, there appear to be two types: a disposable type that looks like a diaphragm (made of polyethylene) and the reusuable bell type (like the Diva Cup) made of latex or silicone (depending on the brand).
It appear that the use of menstrual cups are not associated with TSS, but that there is a slightly higher risk of urinary tract infections and yeast infections. The advice I read is to sterilize your Diva cup well!
I'd add that you should consult your gynecologist for an opinion. They are likely to have a lot of experience with women using menstrual cups.
The Diva Cup in particular is approved by the FDA, Health Canada, and the ISO (international organization). Here is a direct quote from the website: "The DivaCup is latex free and is made from hypoallergenic, top quality silicone, a material that has been used in healthcare applications for over 50 years. This silicone is not the same type of material used in breast implants. No chlorine, dyes, colorings or additives of any kind."
I hope that helps!
Jennifer L. Fee, Psy.D.
The Stress Masters
Dr. Fee is a Psychologist. Dr. Fee's answers are not intended to diagnose or treat any medical or mental disorder. Any information given in a post about medication is for educational purposes only, and primarily to aid you in having an informed discussion with your own Psychiatrist/Physician.