Medela — #1 Choice of Hospitals and Mothers

I went through the trouble shooting with Medela on the phone and they told me it should do that. Its the way the pump lets out the extra air, pressure something like that.

I have had my pump for 2 months and I notice the air leaking around the yellow ''button'' too.  I have no idea if it always did this but I am noticing it now. I was pumping 3 to 4 oz each time but suddenly I am pumping only 1 to 2 oz.  This happened from one day to the next.