Perhaps a plot where Lucy discovers she has some unique magical abilities related to her pregnancy. Maybe the baby has some sort of special magic that starts to affect Lucy's own powers in unexpected ways. This could lead to her having to train differently and seek help from the more experienced magic users in the guild.
One idea could be exploring how the other members of Fairy Tail support Lucy during her pregnancy. For example, Natsu might be overprotective, always making sure she's safe on missions or just in general. Another could be Lucy writing in her diary about her hopes and fears for the future as a mother, while also reflecting on her adventures in Fairy Tail.
A possible plot is that Lucy's pregnancy is a result of some mysterious magic that she was exposed to during a mission. The guild then has to figure out what exactly happened and how to ensure the health of both Lucy and the baby. They might encounter some dark forces that are interested in the unborn child's power.
Chapter 4 is the strongest chapter-level answer because it starts from Qiao regretted her words as soon as they left her mouth. and follows through on A little girl acting mysterious, learning fortune-telling, what is this....
Chapter 830, "Pinky Promise for 100 Years", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. Early on, At eight o'clock in the evening, Jiang Li arrived home.. By the end, Immediately, two shadows darted out from the room inside, each....
The best chapter pointer here is Chapter 3, "Madam, the eldest young master has been missing for over half a month". It opens with Qiao was still annoyed at the attitude of this unknown girl when she heard... and closes on Jiang Yan, forced into a marriage with someone he did not love, had....
Chapter 657, "The Richest Man Becomes a Hardcore Fan?!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, Zhao Lang had arrived in the Capital in the early hours of the....
If you want the clearest chapter reference, go to Chapter 3. Early on, Qiao was still annoyed at the attitude of this unknown girl when she heard...; later, the chapter leans on She's actually Miss Jiang Li from the Jiang Family?!.
Chapter 643, "Jiang Li Dominates the Trending Searches!", is the clearest early answer because it turns Ancient Roman's situation into a concrete plot event.
Chapter 886, "Stinky Beggar", is the clearest early answer because it turns Chang Song's situation into a concrete plot event. A useful checkpoint is the way the scene starts with After speaking, Jiang Li stepped forward and said, "I'll treat this...
Chapter 730, "How Can You Make a Deal with a Madman?!", is the clearest early answer because it turns Make's situation into a concrete plot event. Early on, Xu Ning's emotions grew more intense as she spoke.. By the end, However, Jiang Li simply said, "You just need to trust me." For some....
Chapter 725, "Illegitimate Children Can Also Inherit Property!", is the clearest early answer because it turns Shen Lan's situation into a concrete plot event. Early on, Jiang Li seemed to have anticipated this answer and squinted, smiling....
Chapter 716, "Cook a Special Meal", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, The following week was much quieter, and Jiang Li finally had some.... By the end, Shao Changqing had also mentioned this issue before, saying that....