Neither of you was sure how it happened or what was even going on. At first, you, Sam, and Dean were just sitting at the motel doing research. Then, after a while, you started getting these horrible pains in your lower abdomen.
You and Sam had been sleeping together for a while. You two loved each other very much. Buy you had both always been safe when it came to sex... right?
Well, now you were in the car with Sam as he rushed down the road, listening to you cry out in pain. Dean stayed behind and told Sam to call him with updates later. So it was just you two in the Impala as he sped.
Unbeknownst to you and Sam, the answer to this situation was simple. You had a cryptic pregnancy you hadn't caught onto, and now? You were in labor without realizing it.