Tracy - It is uncommon for Darvocet™ (propoxyphene and acetaminophen) to cause weight gain. If I had to guess, I'd blame the weight gain on the Depo-Provera™ (medroxyprogesterone). I have seen weight gain with this medication.

The pain for which you are taking the Darvocet may cause weight gain in an indirect way. When it hurts to move, you are less likely to do so. Therefore, when you are not as active as you were previously and have the same caloric intake, you are more likely to gain weight. The calories that are normally burned off with activity are not being burned off. This is my guess, though I am more comfortable answering psychopharmaceutical questions.

I hope that this helps. - Cam