Hello and welcome to HCM. Thank you for your query. The causes for fluid in the Pouch of Douglas (POD) can be numerous. Let me list some of the most common ones out for you: -Irritable bowel syndrome -Ectopic pregnancy -Pelvic inflammatory diseases (PID) -Ovarian cysts -Infections and many others. You will have to request your doctor to analyse the fluid in the POD which could be blood, pus or other bodily fluids. This will help in narrowing down the search to find the cause. Once the cause is found, the condition will have to be treated accordingly. In the meantime, please consume plenty of water, abstain from sexual contact till you are diagnosed and do not stress or strain yourself too much. If you notice any symptoms, please report to the ER at the earliest. I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you. Best wishes.