It could be that Aria's creative mind is working overtime. Since she's an artsy person, she might be constantly thinking about her writing, art, or the various events in the PLL story from an artistic perspective. This over - stimulation of her creative thoughts can make it difficult for her to relax and fall asleep.
Aria's friends could engage her in some relaxing activities. Maybe they could do some yoga or meditation together. This would help her to calm her mind and body. Also, they could offer to listen to her if she wants to talk about what's really bothering her. Sometimes just getting things off your chest can make it easier to sleep.
Perhaps Aria has been working hard on some sort of project in the PLL world, like a school assignment related to the mystery they are all involved in. She's tired but determined. The fanfic could show her friends rallying around her to support her, and together they start to piece together more clues about 'A' as she rests and regains her strength.
Another potential antagonist could be a new character. Maybe someone who has a vendetta against Aria's friends and is using Aria as a way to get to them. This new character notices that Aria is tired and weak, so they target her specifically, causing more chaos and confusion in the PLL fanfic world.
It could be due to an unrequited love. If Aramis has feelings for someone in the fanfic who doesn't return those feelings, it can be a source of restlessness. He might be lying in bed, thinking about this person and how to win their heart, thus unable to sleep.
Well, it could be about Aria dealing with the new experience while also handling the drama in PLL. Maybe she tries to hide it from the other girls at first because she's embarrassed, and then as the story progresses, they find out and support her.
Perhaps it's his family issues. Archie has had his fair share of family drama. His father's business problems or his mother's absence could be weighing on his mind at night. In fanfic, this could be explored further, like how he tries to deal with these emotions while still being a hero in Riverdale.
Her friends like Spencer, Hanna, and Emily would likely be there for her. They've been through a lot together in PLL, so they'd probably offer support and understanding.
Well, it could be that Aria's pregnancy is a result of a one - time accident. In the fanfiction, she might struggle with the decision of whether to keep the baby or not. Her friends in PLL, like Hanna, Spencer, and Emily, could have different opinions and offer their support or doubts. And then there's the whole thing about how the pregnancy will affect her future, like her education and career plans.
One common theme could be the reactions of the other characters. For example, how her friends in the PLL group handle the news. Another might be how Aria herself copes with the pregnancy, like dealing with morning sickness and hormonal changes.
I don't have a specific PLL Aria pregnant fanfiction to recommend. However, you can look for it in fanfiction communities. Sometimes, on Tumblr or Reddit's fanfiction - related subreddits, fans might share or discuss such stories. You can also join PLL - focused fan groups on Facebook where members could potentially point you to relevant fanfiction.