Esther Christine Romatua and Silvia Mona 2026. EFFECTIVENESS OF DEEP BACK MASSAGE IN REDUCING FIRST-STAGE LABOR PAIN AMONG WOMEN IN ACTIVE LABOR: A PRE-EXPERIMENTAL STUDY. Zona Kebidanan: Program Studi Kebidanan Universitas Batam. 16, 3 (Sep. 2026). DOI:https://doi.org/10.37776/zkeb.v16i3.2347.