Could retainers cause gum recession?

Gum recession from?: Not if properly made and you keep your mouth clean. If you have gum recession, consult with a periodontist for an evaluation as to cause. Also run this by your orthodontist to evaluate the fit of the retainer. There are numerous types of retainers, both fixed and removable. Not sure what kind you have or are referring to.

Possibly: If the wire is in the wrong position and is resting on the gingiva, then yes. Gingival recession can also be caused by brushing your teeth too vigorously and with too much force. Slowly and gently is the way to brush your gums. Ask your dentist to show you how to brush properly.

Yes: If i'll fitting...See orthodontist for adjustment. If treated with expansion when extraction was a better choice then recession may be a consequence. Overly vigorous brushing and coincidental gum disease may be cause. See a gum specialist, a periodontist.