Tech didn't see babies bladder in Ultrasound?

I had an ultrasound at 20 weeks pregnant and they couldn't get a clear picture of the babies bladder so they asked me to do another one in two weeks. Everything else including the amniotic fluid is perfectly normal. Has anyone else gone through this and do you think this is something my husband and I should be really worried about. Please help, my last pregnancy was a miscarriage so I worry about everything this time around.