Ok heres the deal....I found out I was pregant on June 20th from a Clearblue home test. So, on June 24th, 2008 I got the offical test from a family DR & was sent to do an ultrasound the same day. According to the ultrasound, on June 24th, 2008 I was 7 Weeks & 5 Days far along. I have never had a normal period, they vary from once a month to one every 3-4 months, so the LMP dates are not possiable for me to use to deterime my conception date. Further along on 10/17/08, I had another ultrasound that made my EDD as March 6th, 2009 & stated I was 20 Weeks & 0 Days far along. Because I have never had a normal period, I am unsure as to how accurate these dates are, and for the father its really important to know before the baby comes. How sure can I be as to what the date I got pregant? How long can sperm live inside me before I would acutally become pregant? Are the ultrasound dates really accurate for women who have no LMP date to go by? I dont really understand the extra 2 weeks they add when determining "gestational age", for women who dont ovulate every month, how accurate is the 2 weeks they add for conception date?

Please let me know any info you have about it. Thanks!

Ultrasounds;

7/24/08-7 Weeks & 5 Days
10/17/08-20 Weeks & 0 Days
No LMP date aviable