Expert: Dorothy H, LCCE - 3/16/2011

Question
QUESTION: I would like your insight on who is the father of my unborn baby. Here are the details: My lMP was 01/22/2011 according to my u/s I am 7 weeks and 2 days today. I was with partner #1 on January 28th and with partner #2 on January 29th and again with partner #2 on February 4. I am unsure if I conceived in February from the intercourse at the end of January since the sperm could survive for 5 days. My est due date is October 29. Please help with your expertise advice.

ANSWER: Hi Renee,

Going by your ultrasound and your LMP, it is much more likely that you conceived January 4.

Your ultrasound actually places conception around January 6.  

It is possible that you conceived from sex you had on January 28, but not that likely.

Sincerely,

Dorothy H, LCCE



---------- FOLLOW-UP ----------

QUESTION: Thank you so much for your quick response. I am very concerned that partner #2 is not the father of the child and i'm hoping he is. I am considering amneocentisis or chorionic villus sampling. What advice can you give.

Answer
OK, I seem to have gotten some of my dates in my last answer in the wrong month.

Conception occurred around FEBRUARY 5-6, not early January.  So change all the "January"s in the answer (except for Jan 28) to February.  Sorry about that!  I think you understood what I meant though. :)

To answer your question: Is it possible that Partner 2 is not the father?  It's possible, but extremely unlikely.

In order for that to have happened, the sperm from Partner #1 needed to have lived 5 days (which is the outside limit; 3 days is more reasonable) AND the ultrasound needed to be off by its maximum amount of 2-3 days.  Also, having had intercourse more recently, even if Partner's #1 sperm was still alive when you ovulated, you also had Partner's #2 sperm in there too.

I can't tell you 100% that Partner #2 is the father, but I think it's certainly at least 90-95%.

CVS testing and amnio can also test for paternity and give you that assurance of whether or not Partner #2 is the father, but there are risks of miscarriage with both procedures.  You need to weigh how important the peace of mind of being 100% sure against the risks that you may possibily miscarry.  I would advise you to do the research on both procedures and see what you are comfortable with.