Last week, some "Grey's Anatomy" fans were left confused. Amelia Shepherd spent the episode believing that she was pregnant--because, you know, she's never ever late! She even told Meredith, Maggie, and April that she and Owen were going to have their first baby together. That was until she did the pregnancy test. Fans soon pointed out that she seemed almost relieved that the test came out negative, despite telling people that it was definitely going to be positive and wanting that baby with Owen.

Just why is that the case?

It's all linked to 'Private Practice'

If you didn't watch "Private Practice," it's okay to miss the point. Amelia's storyline from this show has only been mentioned now and then over the last couple of years. It is a major storyline though, and one that will help to explain Amelia's current fears and relief at that negative pregnancy test. While you'll learn more about it here, it's definitely worth spending time watching the episodes to see just how heartbreaking it was for the neurosurgeon.

Amelia ended up pregnant in the spin off of "Grey's Anatomy." However, she and her boyfriend were on drugs at the time, and the baby developed without a brain.

The baby had an active brain stem and lived for 43 minutes, something that she tells Owen during season 11 of "Grey's Anatomy," after the death of April and Jackson's baby boy. She has gone into this more in season 13, but only briefly and it's difficult to know just what she went through. She had to make the choice of termination or giving birth to the baby that she knew would die early on.

'Grey's Anatomy' will understandably continue that fear

We saw with April and Jackson's second baby in season 12 that there was the fear and worry about complications and deformities. While the second baby definitely didn't have the same disease as the first, there was an episode where they feared there was a brain disorder.

In the end, it turned out that the baby was completely healthy, but it was clear that both parents were extremely worried that they would have to go through the birth and death of another child.

Amelia is worried about the same thing. She doesn't want to live through those awful moments and decisions again, and she won't want Owen to go through them. So, when the pregnancy test came out negative, there was a sense of relief. She wouldn't need to go through the fear of something going wrong.

The next steps for Amelia in "Grey's Anatomy" season 13

Caterina Scorsone, who plays Amelia, has said that "Grey's Anatomy" fans should watch "Private Practice." She has also explained that this pregnancy has brought back a lot of memories.

She has been able to compartmentalize a lot in recent years, focusing on no longer being the black sheep of the Shepherd family but the successful chief of neurosurgery at Grey Sloan Memorial Hospital. However, she now has to deal with all the feelings and thoughts she has been pushing to one side.

We'll get to see more about how this affects her in this week's episode, "Roar." It looks like she is going to press pause on the ideas of making a baby, as she deals with the fear and trauma from the death of her son. "Grey's Anatomy" continues on Thursdays at 8pm on ABC.