I'm doing mine tomorrow , at 28 weeks. Different gynae got diff timings for it. Can check with your gynae
For me, it was at my 26 weeks. I think it is usually within ur second trimester.
They did mine at the dn os 2nd trimester
At beginning of 3rd trimester.
28weeks done mine at kkh
Had mine at 29 weeks!
At 25 weeks onwards.
Mine did on week 25
Mid of trimester 2
Mid of 2nd tri