Hi Alan,
I saw that range too, but thought the lower numbers were for later on, just before the birth.
I will have to measure how much water I drink. Before getting pregnant I drank at least two litres a day and I have increased that a fair bit. Maybe I drink three litres now.
It is hot here and I sweat a lot but I try to keep an eye on the colour of my pee because I read dehydration can cause a premature delivery.
I am trying to stay positive. The ultrasound doctor recommended another scan in a month. If it was a big problem I think she would have recommended I come back sooner.