Pregnancy Conception Date Calculation: Understanding Your Due Date & LMP

Question

iam 20 weeks pregnant today my due date is march 18 2009 according to my doctors i got pregnant june 25th and the sed that my last menstrual period was june 11,2008 but i have irregular period and i did not have it on june at all but i had sex june 14,2008 with my ex boyfriend week a week later i got back with my fiance and i did have sex with him around june 25th like my doctors say but if i go back on the calender 20 weeks i got back to june 11...is that the day i got pregnant? i need to know who the father is.please help

Answer
Jennifer,
My answer is based on the fact the I am assuming you have regular periods usually every 28-30 days. Otherwise, this is not accurate. Based on your due date and LMP, you conceived somewhere between June 18 and 25. Hope this helps!! Good luck!