Background: Obstructed labour, a sequel of prolonged labour, remains a significant contributor to maternal and perinatal deaths in low- and middle-income countries., Objective: We evaluated the modified World Health Organization (WHO) Labour Care Guide (LCG) in detecting prolonged and or obstructed labour, and other delivery outcomes compared with a traditional partograph at publicly-funded maternity centers of rural Mbarara district and City, Southwestern Uganda., Methods: Since November 2023, we deployed the LCG for use in monitoring labour by trained healthcare providers across all maternity centers in Mbarara district/City. We systematically randomized a total of six health center IIIs (HCIIIs) out of 11, and all health center IVs (HCIVs), reviewed all their patient labour monitoring records for their first quarter of 2024 (LCG-intervention) and 2023 (partograph-before LCG introduction). Our primary outcome was the proportion of women diagnosed with prolonged and or obstructed labour. Our secondary outcomes included; tool completion, mode of delivery, labour augmentation, stillbirths, maternal deaths, Apgar score, uterine rupture, postpartum haemorrhage (PPH). Data was collected in RedCap and analyzed using STATA version 17. Statistical significance was considered at p<0.05., Results: A total of 2,011 women were registered; 991 (49.3%) monitored using the LCG, and 1,020 (50.7%) using a partograph, 87% (1,741/2011) delivered from HCIVs and 270/2011 (13%) from HCIIIs. Mean maternal age (25.9; SD=5.6) and mean gestation age (39.4; SD=1.8) were similar between the two groups. A total of 120 (12.4%) cases of prolonged/obstructed labour were diagnosed (100 for LCG versus 20 for partograph), with the LCG having six times higher odds to detect/diagnose prolonged/obstructed labour compared to the partograph (aOR=5.94; CI 95% 3.63-9.73, P<0.001). Detection of obstructed labour alone increased to 12-fold with the LCG compared to the partograph (aOR=11.74; CI 95% 3.55-38.74, P<0.001). We also observed increased Caesarean section rates (aOR=6.12; CI 4.32-8.67, P<0.001), augmentation of labour (aOR=3.11; CI 95% 1.81-5.35, P<0.001), and better Apgar Score at 5 minutes (aOR=2.29; CI 95% 1.11-5.77, P=0.025). The tool completion rate was better for LCG compared to (58.5% versus 46.3%), aOR=2.11; CI 95% 1.08-5.44, P<0.001. We observed no differences in stillbirths, maternal deaths, post-partum haemorrhage (PPH) and uterine rupture., Conclusions: Our data shows that LCG diagnosed more cases of prolonged and or obstructed labour compared to the partograph among women delivering at rural publicly funded facilities in Mbarara city/district. We also observed increased C-sections, labour augmentation, and 5-minute Apgar scores. There were no differences in stillbirths, maternal deaths, PPH and uterine rupture. More controlled and powered studies should evaluate the two tools for other delivery outcomes, in different sub-populations.Trial registration number NCT05979194 clinical trials.gov., Competing Interests: Competing interests: No conflict of interest declared