Indeed, birth control pill seemed to be the main cause of my GERD/silent acidic reflux syndrome and its complication in form of chronic sinusitis, which bothered me for 2 years before I found out the real cause. Progesterone (in the case of my prescribed pills it was levonorgestrel) caused stomach acidity, which caused then silent (without burning feeling) acidic reflux/GERD, which then in turn led to chronic sinus infection and dense mucus discharge which came out then either from my nose or through my throat. Difficulties in breathing and constant clearing my nose and throat were difficult to bear and lasted for over 2 YEARS!!!! The doctors were not able to help, apart from maybe suggesting washing my nose with salt (at least I could breathe better). When after reading more and more (I am a biologist) I found about a possible effect of progesterone (and related substances) on stomach acidity, I quitted taking the pill and additionally applied a very strict gluten-free, anti-Candida diet for 3 weeks as Candida systemic infection can also be one of the causes of GERD. I was tested Candida-negative, but read that stool testing can be negative and still there can be Candida as well, so wanted to be sure I do the maximal treatment. And yes! Quitting the pill removed the problem!!! I think diet helped as well but main effect was visible by stopping the pill. I hope it will help some of you with the same problem.