Some list somewhere of YA literature "for adults" recommended Saving Francesca, by Melina Marchetta, and it has the distinction of being the book I was reading during that whole labor & delivery thing. Therefore, my recollection of it is a little fuzzy--however, I do remember liking it! Francesca is accustomed to struggling with her vibrant, overbearing mother, until the day that Mia doesn't get out of bed. To make things worse, Francesca is the only one in her group of friends to begin 11th grade at St. Sebastian's, a formerly all-male school still adjusting to its transition to co-ed status. As Francesca's family falls apart, she loses touch with her old, shallow friends and finds herself bonding with an unlikely group of girls and boys. She is embroiled in an initially adversarial flirtation with House leader William Trombal, who unfortunately already has a girlfriend.
The strengths of Saving Francesca are both the subject mattter (the ripple effect of Mia's depression strains Francesca's relationships with her father and teachers in addition to her mother) and the slow, deliberate filling out of characters through Francesca's sometimes unreliable narration. Francesca's eventual group of friends isn't just a clique-y group of girls as in many teen school-based novels, but a mix of slightly outcast boys and girls whom circumstances have thrown together. The characters are fresh and vibrant, and the ending brings the story to a satisfying full circle.
The author's website. I especially like the Australian part--she lives in Sydney.