That is a very unfortunate problem, and it sounds like it is impacting your quality of life greatly. Pregnancy and childbirth can have many effects on your body (as you know!), and some of these persist after the birth of the baby and for some time afterward. Urinary frequency can be caused by several things, but we do need some more information (and a physical exam, usually) before we can definitively say what is the cause of your complaint. We need to know about the volume that you are urinating when you do go: is it normal, is it that you feel the need to go but then void very little, etc? Then, we need to know if you are having any other symptoms, such as burning with urination, incontinence
, or other issues. From these, we can then narrow down a likely cause. Some ideas that crop up include the thought of a bladder infection (although 18 months is quite a long time), some sort of damage or trauma to the nerves or musculature that control your bladder, or some sort of venous insufficiency that is causing fluid to pool in your legs all day, and then being mobilized and filtered by your kidneys at night when you lie down and the veins don't have to work against gravity. Regardless, this is an entirely appropriate question to ask your obstetrician or primary care doctor
at your next follow up or annual exam.