Amelia (Caterina Scorsone) is pregnant on Grey's Anatomy, but many viewers may not know why she had such an intense reaction to the news if they didn't watch the medical drama's first spin-off, Private Practice. There's a lot more to Amelia's history with pregnancy than just her past relationship with Owen (Kevin KcKidd).

Amelia relapsed into drug addiction on Private Practice, and she fell in love with a fellow addict named Ryan. After a tense intervention by Addison (Kate Walsh) and her co-workers, Amelia and Ryan agreed to get sober after one last drug binge. However, when they woke up the next morning, Ryan had overdosed and Amelia found out a few weeks later that she was pregnant. Not only did she have to face having a child without the man she loved, but an ultrasound revealed that Amelia's baby would be born without a frontal lobe, and thus would die soon after being born.

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Thursday's episode of Grey's Anatomy saw Amelia tell Link (Chris Carmack), the father of her current fetus, the story, but Grey's skipped to saying "his name was Christopher" and avoided all the traumatic details. Those who have been watching Grey's Anatomy all along, or who caught up on Netflix, saw Amelia tell a fuller version of the story to Owen a couple of seasons ago, but they still haven't seen her heartbreaking arc for themselves.

To get the full picture, here are the episodes of Private Practice you need to watch to know Amelia, and Christopher's, full story. The series is available to stream on Hulu.

Caterina Scorsone, <em>Grey's Anatomy</em>Caterina Scorsone, Grey's Anatomy

Here's where to start:

Season 5, Episode 8: "Who We Are"

Grey's fans know Amelia is an addict, but this episode shows her at her absolute worst. Finally at their breaking point, her friends and co-workers stage an intervention to try and get her off the prescription drugs she's been popping like candy. She's completely off the rails, but the one thing that is clear is that she loves Ryan (Wes Brown). After the intervention, they make a pact that they'll have one more binge and then check into rehab, get clean, and start a family. They do a line of drugs, go to bed... and Amelia wakes up to find Ryan dead of an overdose beside her.

This is important because when Amelia finds out she's pregnant later (and now again on Grey's) we know it wasn't an accident. She and Ryan really wanted a family together, but then the worst possible thing happened.

Season 5, Episode 19, "And Then There Was One"

Skip forward a bit and Amelia has successfully completed a stint in rehab. She's sober, pregnant, and ready to meet her baby during her first ultrasound. However, it's only a few moments of joy before Addison drops a massive truth bomb about the baby's development, and Amelia must decide what she wants to do with the devastating information.

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Season 5, Episode 21, "Drifting Back"

Fast-forward a little more and Amelia is getting closer and closer to carrying the baby to term. She's decided that she will donate her son's organs to help save other newborns in need. However, with each passing day the pregnancy gets harder and harder as all of her co-workers hover over her to make sure she isn't resorting to drugs to cope. The desperate lengths she goes to in order to maintain sanity without slipping back into addiction are heartbreaking, and they will make you marvel at how one person can withstand that amount of pain.

Season 5, Episode 22, "Gone, Baby, Gone"

If you can only watch one episode, make it this one. Amelia finally gives birth to her son and gets to hold him for a minute before making one of the most painful decision that any mother could ever make. What's even more heart-wrenching is the speech she gives to Sam (Taye Diggs) to convince him to do the surgery she needs to complete the birth plan. Stock up on tissues, because this episode will not only help you understand Amelia in a whole new light, but it will make you astounded that Scorsone doesn't have all the Emmys.

Grey's Anatomy's Caterina Scorsone breaks down Amelia's "emotional catatonia"

Now you understand that Amelia becoming pregnant on Grey's Anatomy is no small thing, and her decision to trust Link enough to continue with this pregnancy says volumes about how much she has grown to care about the Ortho God. To understand why Amelia might freak out or have extreme reactions to any hiccups with this pregnancy, the arc on Private Practice is essential viewing. Fingers crossed that this situation has a much happier ending, because Amelia deserves it, and our nerves can't take it.

Grey's Anatomy airs Thursdays at 8/7c on ABC.