When was my baby conceived if on July 21st I 11 weeks and 1 day according to ultrasound?

To calculate the estimated date of conception (EDC), you need to subtract the number of weeks and days from your ultrasound result from the date of the ultrasound.

Since you are 11 weeks and 1 day pregnant according to the ultrasound on July 21st, we can work backward to find the EDC:

1. Start with the ultrasound date: July 21st.

2. Subtract 11 weeks and 1 day from July 21st: 11 weeks = 77 days, so 77 days before July 21st is April 14th.

3. Since there is an extra day (the 1 day in "11 weeks and 1 day"), we need to go back one more day, which brings us to April 13th.

Therefore, the estimated date of conception is April 13th.