Most often: food! The first thing that comes to mind, of course, is diabetes. But for many pregnant women, kidney function changes. Often, the same morning a pregnant women drinks a big glass of orange juice, we'll find sugar in her urine sample. However, that is not to say we ignore the findings -- all pregnant women do get tested for gestational diabetes between 24 and 28 weeks.
Glucosuria. Normal blood sugar is maintained by adequate Insulin production and utilization. If you are a diabetic and sugar remains high your kidneys will try to remove sugar to normalize blood levels. This is not ideal. It means your blood level is remaining above 250 at times and also sugar in your urine can allow for infections.