What Causes Abdominal Bloating And Weight Gain During Menopause?

Hi, I am 52 years of age and going through menopause. Over the last few months I have experienced weight gain and have noticed that I always seem to be bloated. Recently I had an ultrasound as I have been experiencing a bulging feeling on the lower right side of my pelvis. The ultrasound revealed I have a small pocket of extraluminal fluid in the posterior pelvic cul-de-sac. I am waiting to see a gynaecologist to discuss this but am very concerned that it is ascites or what could have caused this fluid. I had a hysterectomy at 39 years of age and my ovaries are apparently healthy with no adnexal mass showing on the images. Is it normal to have this fluid and should I be worried? Many thanks for your help.