Yes, there are. However, the quality can vary greatly. Some might focus more on the emotional aspects of Ed and Winry becoming parents, like their fears and joys. Others could be more centered around the events in their world that are affected by this new development. It really depends on what you're looking for in a fanfic.
You can start by looking on fanfiction websites such as Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, including Fullmetal Alchemist where Ed and Winry are from. Another option is FanFiction.net. It has been around for a long time and has a decent amount of Ed and Winry fanfictions as well.
One popular Ed and Winry fanfiction might be those that focus on their post - series life together. Maybe a story where they build a family and Ed finally settles down from his adventures. Another could be a story set during their childhood, exploring their early bond and how it developed over time. There are also fanfictions that put them in alternate universes, like a modern - day setting where they meet in a completely different context.
A good one often has well - developed characters. It should stay true to the personalities of Ed and Winry from the original series. For example, Ed's determination and Winry's feistiness should be there.
One common theme is anticipation. It's all about waiting for the baby to arrive, like in many fanfictions where Ed and Winry count down the days. Another theme is the change in their relationship. They go from being just a couple to soon - to - be - parents, which brings a whole new level of closeness and responsibility.
There's 'The Family Expansion'. This fanfiction shows how their friends react to the news of Winry's pregnancy. Ed is portrayed as a very protective husband, and there are some really heartwarming scenes where he talks to the unborn baby. It also delves into how their relationship changes with this new development.
One interesting story could be about Ed and Winry's baby showing early signs of alchemy talent, just like its father. It might involve the baby accidentally transmuting simple objects and the couple's humorous attempts to deal with it.
There are many out there. Some fanfictions might focus on the early days of Ed and Winry's relationship, like when they were just kids. 'Ed and Winry: Childhood Memories' could be a title in that regard, showing how their bond started. Others might look at how their relationship evolves during the main events of the series. And then there are those that project into the future, imagining their life as a married couple, with titles like 'Ed and Winry: Married Life'.