Possibility of Pregnancy- Variables included

[madatself07]

Long story short. I had unprotected sex with a 40 year old woman that was ~14-16 days from her last period which would mean she was ovulating (or possibly just past).

I did not ejaculate in her.  (Withdrawal)

Approximately 40 hours later, she took a Plan B pill.
Obviously I am still concerned and I know it was a very dumb move to start with... Lesson learned.

Variables:
This woman previously had cancer and took very powerful chemo drugs that are known to affect fertility (cisplatin). She also currently has thyroid issues and takes medicine for it.
I am a smoker and just had a traumatic physical experience which I believe could affect my sperm count.

My concern is that: 1) Plan B is known to stop ovulation. However, in my situation, ovulation probably had already occurred, so what is the effectiveness of plan B actually working? 2) Does our fertility issues plus plan b, plus lack of ejaculating, plus her age help?  I think it does, but I am trying to quantify how much? What are the probabilities?
3) Which of the factors is going to be the most determinative?

[madatself07]

Thanks Dr. Brown!  Sounds like you are saying that the odds of her being pregnant are pretty low?

However, I'm curious about the 40 hour window. I guess my fear is that the potential was for fertilization during that window(this of course assuming that somehow there was sperm there). Would Plan B somehow be effective in some other way?

Another general question for my own knowledge. Are there times when women will have a regular period, but will not ovulate?

[Elaine Brown, MD]

Hi!
If your friend was my patient, I would advise her that taking the Plan B was an excellent move.  If she had already ovulated for this cycle, there is no concern about pregnancy.  If not, Plan B will delay that.  She will need to do a pregnancy test if she does not have her normal menstrual period.  There are some current studies that show that there may NOT be sperm in the pre-ejaculate--in which case no chance for pregnancy.  Those two are probably the most important factors in your favor.
Good luck!
Dr B