Curious

There's no way to know until they're born. Late term ultrasound isn't accurate and has been linked to higher rates of csections. 

Not always accurate. My dr was worried about me having large baby for my size. Measure 8-9lbs .... he was 6lb 14oz. Healthy at birth :) unless you have GD weight is not going to make a difference in you pushing/tearing unless you have a very large baby in which case your dr would tell you becuase you may need C section which is not common.

Ultrasounds are not an accurate way to determine the weight of the baby. I was told my daughter was 8 lbs at 35 weeks and she wasn't born until 41+3 only weighing 6lbs 15oz. As someone else mentioned, women end up being talked into c-sections because the Doctor's are worried their baby is too big based off an ultrasound and then once they're delivered they are actually 2 lbs less than expected. A good midwife can predict the baby's actual weight just by feeling your belly, at least mine did. I think she was only off by one ounce and laughed at what I had been told via ultrasound.

Nope ultrasound is the only way and it isn't always 100% accurate for weight either