How likely is it that i can possibly be pregnant after the first time with my fiancee? i am a 8 year transplant recipient with irregular periods. my last one was in september and it was very light. he pulled out early but i am not sure if he did in time.

This : This is an educational comment to add to dr seeley's excellent response. Prior to ejaculation; pre-ejaculate which is a clear fluid; is released from the tip of the penis. Although the concentration of sperm in pre-ejaculate is much lower than that of ejacualate if can still lead to pregnancy. The pull out method during sexual intercourse is far less than ideal as a way to prevent pregnancy. Recommend using an appropriate method of birth control. Take care.

Congrats : Congrats on 8yrs years post transplant! pregnancy is unlikely 'with irregular periods' because you may be having 'anovulatory bleeding'. In other words --you're not ovulating every month on a cycle. Having said that --pregnancy is still possible because ovulation can happen 'out of the blue'. So just take better precautions and check pregnancy tests for the next 3 weeks. The new home tests can be + within a week.