How accurate are ultrasounds for determining weight?

meagan β€’ ♑𝓢𝓸𝓢𝓢𝔂 𝓸𝓯 𝓽𝔀𝓸 β™‘

I had an ultrasound this morning and was told my baby boy is in the 70th percentile for his weight. He's 4.7 pounds they said. I'm 31+5. I have another ultrasound in a month to check again, they said if he's too big I'll have to be induced. Any one have experience with this? I don't want to be induced again πŸ˜“