SOLVED. Romance (3 stories in one book?) / 3 sisters go back to their parents house to celebrate their "rewedding" (?) (american west side, Las Vegas maybe ?) all end up pregnant, it's the whole plot. Spoilers ahead. [s]

[Juels]

Baby Fever by Kasey Michaels?

"Three mothers-to-be are about to receive an unexpected baby bonus--a husband! The Parrish sisters' biological clocks are ticking louder and louder. All three decide to take matters into their own hands, and find a little help when they least expect it!"

[Juels]

You're welcome.