Pregnancy Timeline: Determining Conception Date & Due Date

Question
i only had sex two times in july. july 4th and july 21st or 22nd.i
went to the doctors and they said that my conception date was
the 21st and she did that by my ultrasounds and i wasnt sure
when my last period was but i think it was around july 8th,well
the doctor said it had to be around then and that sounds right.i
was just wondering if i was pregnant from the 4th or 21st? my
due date is april 14 can you help me?

Answer
If your last period started on July 8, ovulation occurred on July 21 and you could have conceived if you had unprotected sex on July 21,22,23, or 24. You could have conceived if you had sex on July 21 or 22, but you could not have conceived if you had sex on July  4 because you had not ovuluated yet.