Hi sis! BPS (Biophysical Profile) ultrasound ay dapat gawin starting around 28 weeks onwards, especially kung may concerns like gestational diabetes or high blood pressure ka, pero normally ginagawa siya towards the end ng pregnancy like 32-36 weeks na para ma-monitor ang baby's health bago magdeliver. Hindi siya parang pelvic ultrasound lang, mas detailed ito kasi tini-check nila ang amniotic fluid, baby's movement, breathing, at muscle tone, so mas matagal ang session at mas focused sa kung okay ang baby. Best talaga na tanungin mo OB mo kung kelan exactly for your situation kasi every pregnancy ay different, pero alam ko a few of us dito sa community nag-have ng BPS around that timeframe na!