Hi, I recently found out I was pregnant. My last period was october 23rd and my cycles are consistant with 27-28 cycle days. I had my first ultra sound yesterday 12-19 and she said the baby was 7weeks and 1 day. What does that mean? The baby was concieved 7weeks and 1 day ago? I had sex Nov1st, 5th, and 9th, which day did I concieve then? If I concieved later than the 9th my luteal phase would be way to short considering I was expecting my period on Nov 19th? I feel like I should be due earlier than August 5th...
Did your last period START on October 23?
Usually doctors base dates on your LMP. Why? Because almost all women know exactly when that was.
You'd normally ovulate between about days 11 and 16 of your cycle so November 3 to 8. Sperm can survive about 5 days, the egg only 48 hours after ovulation.
It really could be any of the days. You don't get pregnant immediately. It takes several days at least. After about the 10th it would be unlikely you'd conceive. Your fertility would be decreasing.
No test can pinpoint exactly how old the fetus is. Like people, we all develop differently.
Your doctor is basing the date on about an Oct 30 LMP.
Remember too, the due date is approximate. It can vary.