A new survey has found it may be difficult to shop for mom.

Nearly nine out of 10 respondents in a poll conducted by coupon site RetailMeNot say they know or suspect that their mothers have returned at least one present they've sent mom for Mother's Day.  

And, don't think you can get away with not getting mom something this year. 

With the holiday approaching next Sunday, May 11, most mothers surveyed say they're expecting some kind of token of affection from their kids.

Six out of 10 say they think their immediate family should spend money on a thoughtful gift.

The most popular choice for moms this year will be a certificate to help her pamper herself with a day at the spa or a nice restaurant.