Often, the theme of family values is prominent. In these fanfictions, Joey and Lauren learn to create a loving and stable family environment for their baby. Also, the theme of sacrifice is there. They may have to sacrifice some of their personal time or hobbies to take care of the baby.
One common theme could be the couple's journey through the pregnancy, dealing with things like doctor visits and preparing for the baby. Another might be how their relationship changes during this time, perhaps growing stronger or facing new challenges.
One great Joey and Lauren baby fanfiction is 'A New Beginning for Joey and Lauren'. It beautifully depicts their journey into parenthood, filled with cute moments of them learning to take care of their baby. Another one could be 'Joey, Lauren and the Little Miracle' which focuses on how their baby changes their lives for the better.
There are so many fanfiction stories out there, and finding the exact 'lauren and joey pregnant fanfiction' can be a bit of a hunt. Maybe start by looking at the tags on the relevant fandom pages. If it's a popular pairing in a well - known fandom, chances are there are some stories with that theme. You could also ask in relevant fan communities or forums.