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Hi, It's Dr. C. Board certified Ob-gyne. I can help you today.
I'm sorry to hear about this confusion. Let me look at the dates. It will take just a few minutes. Then I'll get back to you with what I think
Ultrasounds are the most accurate way to tell conception date. If the ultrasound was done before the end of January, it's accurate to within 3 days. In that case, the most likely day of conception was November 7th with a range of November 4th through the 10th.
But because sperm can live for 3-5 days, sex as early as October 31st could have resulted in this pregnancy.
I hope this is good news. Please let me know if I can clarify anything or add details. I want to be sure you have the most helpful information for your situation.
If the ultrasound wasn't done until the beginning of March, the error would be bigger. The range would be November 7th with a range of November 1st to 14th. With sperm living for 5 days, the earliest sex would be October 27th. So yes sex on October 30th could have resulted in this pregnancy.