The aim of this work was to evaluate the relationship of the maternal mortality ratio due to obstetric haemorrhage (MMROH) with the national blood donations, particularly O RhD negative (Oneg) before and during COVID-19 pandemic. The maternal mortality ratio is increasing in Colombia, yet little is known regarding the relationship between blood donations and maternal mortality due to obstetric haemorrhage. A retrospective cross-sectional study between January 1, 2018, and December 31, 2021, was performed, to assess MMROH compared to the blood donations notified to the Colombian National Haemovigilance System, through non-parametric methods. Because a relationship between blood donations and MMROH was identified, the analysis was expanded from 2009 to 2017. In 2020, Colombia increased the MMROH by 32% compared to 2019 which coincided with the lockdown period to contain COVID-19. An inversed relationship (SumD2 = 631.0; rs = -0.7335; p 0.01) between blood donations, particularly Oneg (SumD2 = 652.0; rs = -0.7912; p 0.002) and MMROH was identified. For the years 2015-2019 and 2021, the annual mean MMROH was 8.5 ± 0.5 per 100 000 live births when the annual mean blood donations was 18.2 ± 0.4 donations per 1000 people and the Oneg was 1.0 ± 0.0 donations per 1000 people. In contrast, the years 2009-2014 and 2020 displayed an annual MMROH of 12.6 ± 0.8, when the annual collection of blood was 16.4 ± 0.8 donations and the Oneg was 0.9 ± 0.0, p < 0.001. There was an inverse relationship between blood donation, mainly Oneg, and maternal mortality from obstetric haemorrhage. However, we recognise these deaths could be related to other reasons, especially when they occurred in rural areas with limited access to medical services.