Hey mama! So basically, ang ultrasound mo around 11-14 weeks (the first trimester scan) ay hindi na siya replacement sa mas detailed na scan mo sa 20 weeks, na yun ang talagang nag-check ng baby's anatomy in detail for any possible issues. Both scans are important kasi may different purposes, the early one ay mainly para sa dating at viability, pero the 20-week scan is the one na super detailed talaga para sa birth defects screening. I'd definitely ask your OB kung bakit ito sinabi, baka may specific reason sila or may kailangan pang i-check during your anatomy scan!