INTRODUCTION: To determine the effect of implementing a standardized preterm labor (PTL) algorithm in a multiple hospital health system. METHODS: We performed a prospective evaluation of patients presenting with PTL at 34 hospitals within the Trinity Health System. Prior to implementation of a PTL algorithm, patients presenting with PTL symptoms were assessed in a manner determined by the clinician. After training, a PTL evaluation algorithm was implemented system-wide as a quality improvement project. The algorithm detailed the use of sterile speculum examination (SSE), fetal fibronectin (fFN) collection and transvaginal ultrasound cervical length (TVCL). Pre- and post-implementation data were compared using Chi-Square tests. Negative predictive value (NPV) was calculated for fFN and/or TVCL testing. RESULTS: 1,826 women (557 pre- and 1,269 post-implementation) were included in the quality improvement project. The rate of SSE (pre: 51%, post: 68%; P<.0001) and fFN performance (pre: 23%, post: 36%; P<.0001) increased after utilization of the algorithm, while the rate of TVCL remained unchanged (pre: 13%, post: 14%; P>.05). Maternal admission rates decreased with algorithm utilization (pre: 21%, post: 15%; P<.01). Women presenting with PTL symptoms who were not evaluated by fFN or TVCL delivered within 2 weeks at a rate of 24%, while those who received either fFN, TVCL, or both had a rate of 6% (P<.0001). NPV for fFN and/or TVCL diagnostic testing for delivery within 2 weeks is 96.8%. CONCLUSION: Use of the PTL algorithm improved the clinical evaluation of patients in our health system and decreased the maternal admission rate.