Effective screening and referral practices for perinatal mental health disorders, perinatal substance use disorders (SUDs), and intimate partner violence are greatly needed to reduce maternal morbidity and mortality. We conducted a randomized controlled trial from January 2021 to April 2023 comparing outcomes between Listening to Women and Pregnant and Postpartum People (LTWP), a text- and telephone-based screening and referral program, and usual care in-person screening and referral within the perinatal care setting. Participants assigned to LTWP were three times more likely to be screened compared with those assigned to usual care. Among participants completing a screen, those assigned to LTWP were 3.1 times more likely to screen positive, 4.4 times more likely to be referred to treatment, and 5.7 times more likely to attend treatment compared with those assigned to usual care. This study demonstrates that text- and telephone-based screening and referral systems may improve rates of screening, identification, and attendance to treatment for perinatal mental health disorders and perinatal SUDs compared with traditional in-person screening and referral systems. System-level changes and complementary policies and insurance payments to support adoption of effective text- and telephone-based screening and referral programs are needed.