I know 'The Miracle of Ayato and Yui's Child'. In this fanfic, the pregnancy is a catalyst for a lot of character development. Ayato starts to question his own nature and how he can be a better person for Yui and their unborn child. It's really interesting to see how the other characters in the Diabolik Lovers universe react to the news as well.
One great fanfic you could look for is 'A New Beginning for Ayato and Yui'. It beautifully explores their relationship after Yui discovers she is pregnant. It delves into how Ayato, who was initially shocked, gradually becomes a very protective and loving partner. The story also shows Yui's strength as she prepares for motherhood in such a complex world of Diabolik Lovers.
There's also a fanfic named 'Ayato and Yui's Pregnant Journey'. It focuses on the emotional rollercoaster that Yui goes through during her pregnancy. She has to deal with her own fears, the expectations of the vampire world, and Ayato's sometimes erratic behavior. But through it all, their love for each other seems to grow even stronger.
Look to Chapter 113 for the clearest answer. It begins with The next day, Jiang Lili was up before dawn as usual., keeps building through But this time was different; as she got dressed and opened her room door,..., and lands on If things are really as you say, that is indeed quite serious..
If you want the clearest chapter reference, go to Chapter 150. Early on, Upon hearing the first part of Jiang Li's words, Zhang Cheng dismissed...; later, the chapter leans on After all, that information could be found online..
If you want the clearest chapter reference, go to Chapter 107. Early on, On the plane, when He Yun had taken off his mask and greeted her...; later, the chapter leans on She had also figured out his current predicament of being trapped by....
A practical answer is Chapter 152, because it turns the idea into a concrete scene. The chapter opens with While most of the villagers of Chixia Village were gathered at the village..., adds pressure through Is every man in the world supposed to be hers?], and ends on That shouldn't be." Zhao.
If you want the clearest chapter reference, go to Chapter 131. Early on, Just around mealtime, Director Sun came over pushing his small food cart.; later, the chapter leans on There was a loudspeaker tied to the top of the cart, which was....
The best chapter pointer here is Chapter 159, "The Other Flying Guest is Actually Him?!". It opens with Seeing the red light of the camera turn on, Su Yinwan looked at the... and closes on Shang Shaobai, who was browsing through files, received a call from his....
The best chapter pointer here is Chapter 134, "Being able to accompany Miss Jiang is my good fortune". It opens with After a brief noon rest, the production team was up to their antics again. and closes on [Are you kidding me, is Jiang Li putting on an act again?.
Look to Chapter 151 for the clearest answer. It begins with Now it was Zhang Cheng's turn to be confused., keeps building through The problem lies with He Yun?, and lands on I will have my assistant pay the bill.. That makes it a reliable bookmark because the chapter closes with Was he...