Question: This question would mostly be for an OBGYN. Please help. I was recently informed by my fiance that she cheated on me and are unborn daughter might not be mine.  I will provide all the dates that i know. I know her LMP was 2/27/2016. She cheated on the 5th day of her period 3/2/2016. Her period was only 5 days long if that means helps any to you. Also she sometimes has irregular periods as the dont always land on the same date and not always as long as normal.  At the beginning of april she had a positive pregnancy test. It was in the first week. On 5/5/2016 she had her first ultrasound and the OBGYN put the GA at 9wks and 3 days. And the CRL was 26.96mm. From all the research ive done im pretty sure the baby is mine. Her ovulation day should of been around 3/13/2016. Which would of been longer than sperm his sperm could survive. I have also been told that the first 8-10days from the start of a period are considered safe days as its extremly hard to get pregnant. I also have been told sperm are most fertile within 24hrs and alot doe by 3 days and by 5 days there all mostly dead, is this true. Also i read something about hostile cervical mucus. What is this?  What are the chances that it is my baby daughter? Please help asap.

is there any hostile cervical mucus during the period days that kills sperm

So with everything being said the baby is mine

well Dr. with everyrhing you have told me and from everything i have read, i feel that there is no need for a paternity test. it was just a bad concidence that it happened this way and i feel much more at ease sonce speaking woth you. Again thank you very much