BackgroundBirth preparedness and complications readiness (BP/CR) is an effective strategy to reduce maternal and newborn morbidity and mortality.AimTo assess the effect of educational interventions on women’s knowledge and attitude regarding BP/CR in southwest Nigeria.MethodsA quasi-experimental study was carried out over 1 year (May 2019–April 2020) in Lagos, southwest Nigeria. Intervention was delivered using multiple educational methods: health education sessions, information, education, and communication materials, and mHealth. A total of 2600 women were recruited by multistage sampling. Data were collected using interviewer-administered questionnaires and analysed with Epi Info and SPSS V.25 software. Summary and inferential statistics were done involving four-way analysis. The level of significance was set at p<0.05. Regression analysis applied to intervention group (IG). A 50% cut-off was used to categorise respondents into adequate and inadequate knowledge of BP/CR.ResultsMean age of the respondents: 31.2±5.4 years for the IG, 30.4±6.0 years for the control group (CG); p=0.007. Most women in both groups had formal education, were employed and had their last antenatal care in health facilities. At baseline, both groups had overall inadequate knowledge of BP/CR which improved significantly post intervention only in the IG. For the IG: 9.4% (pre), 52% (post), (p<0.001); CG: 0.2% (pre), 0.5% (post), (Fisher’s exact p=0.624). Most respondents in both groups had a positive attitude to BP/CR, the intervention had no significant influence on this in the IG (p=0.504).Predictors of adequate knowledge of BP/CR included being of Yoruba tribe, (adjusted OR (AOR) 2.83, 95% CI 1.06 to 7.54), being employed, (AOR 1.31; 95% CI 1.04 to 5.87) and having a baby 6 months prior to the study (AOR 2.62; 95% CI 1.31 to 5.24).ConclusionFindings have implications for the design and implementation of relevant policy and community interventions to reduce maternal mortality. Further research can examine the role of financial exclusion in inadequate knowledge.