Why does my ultrasound gestational age of 5 weeks on March 16 not match with conception date of February 14 I had a positive test on February 28 and a miscarriage in January and never had a period?

Ultrasound gestational age is calculated from the first day of your last menstrual period (LMP), which can lead to discrepancies if you have irregular cycles or if you experienced a miscarriage before your current pregnancy. Since you did not have a period after your miscarriage and conceived around February 14, the ultrasound may not align perfectly with your conception date due to these factors. The date of your positive test on February 28 suggests that implantation likely occurred shortly before that, reinforcing the possibility of a gestational age based on LMP calculations. It's best to discuss these discrepancies with your healthcare provider for personalized insights.