Precum?

Sometimes my boyfriend and I will have a little bit of unprotected sex before we really go at it. Anyways, he thinks he felt some sort of release. Was probably just precum though as he has to really go at it to "get off". So can precum get you pregnant? Does it contain any sperm? Should I be worried? We would be fine if I got pregnant. Just want to know if that's a possibility.

The 14th is the day we did it.