If i had an ultrasound done on april 21st that said i was 4 weeks and 4 days pregnant, around when would i have conceived?

April 3: You most likely conceived around april 3. You should be aware; however, that is is not precise. It is based on averages. It may be off a day or two for a given women. Also, sperm can hang around for 3 days so the day you had intercourse may be different than the day of conception.

2 weeks ago : The ultrasound measurements are usually based on your last menses not ovulation so it is usually off by two weeks. However, 4 weeks is usually very early to see anything but possible. The doctor may have already subtracted the two weeks. Check with the doctor.

Uncertain: There should be no visible signs of pregnancy at 4wks 4dys aside from possible thickening of the lining of the uterus. It would be unusual to even resolve the gestational sac at that stage. The sac starts to be visible around 5 weeks and fetal heart activity is visible at around 6-6.5 wks. Maybe the tech was counting from presumed date of conception which would have made you 6 wks 4 dys ?