Expert: Dorothy H, LCCE - 3/19/2010

Question
Hello Dorothy,

My girlfriend and I have intercourse without a condom on 2/27/10.  I did pull out at least 5-10 prior to ejaculation.  She saw her OBGYN yesterday 3/18 and was confirmed pregnant by sonogram and was told that the date of conception was 2 weeks and 6 days ago which would be 2/26/10.  She was also told that she was 5 weeks with a due date of 11/22/10.  My questions are as follows:

1) It is possible that I made her pregnant?
2) What is the margin for error based on provided conception dates?
3) What is the absolute earliest that intercourse could have occurred based on the provided conception date?

Your response could really help me in my current situation.

Best Regards,

Dan Thompson

Answer
I'll do my best to answer your questions.

1) Yes it is.  If you have sex without a condom, there is pre-ejaculate which contains sperm, which could have gotten her pregnant.

2)  I would suggest having another ultrasound around 8-10 weeks - it will be more accurate - within +/- 3 days.

3) I don't have enough information to answer that question - however, sperm can live 3 days (sometimes 5 days) in the vaginal tract.

If you and your girlfriend have a good relationship and you had no reason to think that she was sleeping with other men, there is no reason to think that you aren't the father.   If you are unsure, ask if she can get a 2nd ultrasound about 4 weeks after the first one. The second one should have a +/- 3 day margin of error.  You can also have a paternity test done after the baby is born.