Ovulation Timing After Missed Birth Control Pills: What You Need to Know

Question
So if you miss two pills, and that can happen at any time during the month, if I am correct, how many days after missing pills would your body ovulate? Does it happen right away, or does it take a few days for your body to go thru the process?  Or should I just assume, based on the due date of June 21st, that ovulation had to have been around the 27th of September, regardless of when I missed my pills, because I obviously would not know when that was. Thanks for all your help.
-------------------------
Followup To
Question -
I am 30, this is my first pregnancy.  I was on the birth control pill when I concieved and am not sure of my LMP.  I wondered how accurate due dates are when you dont know your LMP and how birth control falls into the whole process of conception, when you aren't supposed to be ovulating.  At 20 weeks and 3 days, I was given a due date of June 21st.  I am trying to figure out about when I would have concieved, considering I was on the pill, but obviously as some point I ovulated and became preganant.  How accurate is due date in this case and could I have concieved on Sept 29, 2005.  Thank you for your help here...it means a great deal - with out knowing my LMP - all these due date calculators make it quite complicated.  
Answer -
A sonogram that is taken around 20 weeks is very, very accurate. You did not mention the date of the sonogram. However, if they gave you a due date of June 21  due to the results of the sonogram that was tqaken at 20 weeks 3 days. your last period must have started on September 14, and you would have ovulated on September 27 and could have conceived on September 26,27,28,. or 29. It is highly unlikely that you would have ovulated if you tokk the pills every day without fail. If you missed two pills, you could have ovulated.

Answer
Ovulation occurs when estrogen levels drop, an LH (luteinizing hormone) surge has occurred, and pregesterone starts to rise. Ovulation usually occurs around cycle day #14 and you can conceive if you have sex on cycle day #13,14,15, or 16.  When you are taking pills, and you miss two or more pills, you may ovulate on cycle day #13,14,15, or 16. If you miss a few pills later on in the cycle, you will not ovulate, but will start to bleed.We suggest that if you miss one pill, take two the next day. If you miss  two pills, take two the next day and two the day after. If you miss three pills in a row, throw away the pack and start a new pack on the following Sunday. You will start to bleed within a few days.If, based on the sonogram, your due date is June 21. Since a pregnancy is 280 days from the first day of your last period, your LMP had to be September 14. Ovulation is 14 days from the first day of your period (Setember 27) Since you can conceive if you have sex one day prior to ovulation and up to two days after ovultion, you could have conceived on September 26,27,28, or 20.