Despite diagnosis being an important part of clinical or medical consultations, the diagnosis might fail leading to adverse effects. This is a global problem, where developed and developing countries go through. In sub-Saharan Africa, variations between initial diagnosis and final diagnosis lead to diagnostic errors with high maternal mortalities. In Kenya, a lot of measures have been put in place but still, variation in diagnosis appear to have become rampant. Bungoma county is one of the counties with a high mortality ratio, especially for pregnant women attributed to the variation between initial and final diagnosis. Therefore, it was crucial to investigate the variation between initial and final diagnosis in relation to obstetric outcomes at hospitals in Bungoma County. The cross-sectional research design was used (Bungoma and Webuye hospitals). Systematic sampling was used to obtain 384 respondents after proportionate allocation to each hospital, and purposive sampling to select 8 health care workers as key informants. Data was collected using a structured questionnaire and an interview guide. The pre-test was done with validity established through crosschecking and reliability calculated using the Cronbach method (0.89). Using a statistical package for social sciences version 25, descriptive and inferential statistics was run where chi-square and odds ratio was used to determine the influence between variables, significance and prediction. The study revealed a variation between initial diagnosis and the final diagnosis was 20.8% while diagnostic errors were significant predictors of obstetric outcomes among post-natal mothers at level five with a p-value of 0.045 at a significance of 5%(P=0.045). Demographic characteristics showed no relationship with obstetric outcomes (P=0.54>0.05). Matched diagnostic had no variations (N=327, M=1.00, SD=0.000); while unmatched diagnostic had variations (N=327, M=1.82, SD=.384). There was a relationship between diagnostic errors and obstetric outcome (ꭓ2 (1) = 251.86, p< .001). An association between diagnostic error with unsafe obstetric outcomes was significant at the odds ratio of 2.03(OR 2.03, 95% CI 1.31–2.16). The study demonstrates that a correct diagnosis is a viable strategy in preventing unsafe obstetric outcomes and by extension minimizing morbidity and mortality among pregnant women. The study concluded that there was a variation between initial diagnosis and final diagnosis which had an adverse obstetric outcome. it was recommended to build capacities for the health workers in order to address increased diagnostic errors.