OBJECTIVE: To evaluate whether MAMAACT, an antenatal care (ANC) intervention, aiming at reducing ethnic and social disparities in perinatal mortality, affected perinatal health outcomes.

DESIGN: Cluster randomized controlled trial.

SETTING: 19 out of 20 maternity wards in Denmark.

POPULATION: All newborn children within a pre-implementation period (2014-2017) or the implementation period (2018-2019) (N=188 658).

INTERVENTION: A six-hour training session for midwives in intercultural communication and cultural competence, two follow-up dialogue meetings, and health education materials for pregnant women on warning signs of pregnancy complications ꟷ in six languages.

METHODS: Nationwide register-based analysis of the MAMAACT cluster randomized controlled trial. Mixed-effects logistic regression models were used to estimate the change in outcomes from pre- to post-implementation in the intervention group relative to the control group. Results were obtained for the overall study population and for children born to immigrants from low-middle income countries, separately. Models were adjusted for a priori selected confounders.

OUTCOME MEASURE: A composite perinatal mortality and morbidity outcome, including stillbirths, neonatal deaths, Apgar score <7, umbilical arterial pH <7.0, admissions to a neonatal intensive care unit (NICU) >48 hours, and NICU admissions for mechanical ventilation. Additional outcomes were the individual measures.

RESULTS: The intervention increased the risk of the composite outcome (aOR 1.16, 95% CI: 0.99-1.34), mainly driven by differences in NICU admission risk (composite outcome excl. NICU, aOR 0.98, 95% CI: 0.84-1.14). The intervention slightly increased the risk of low Apgar score and decreased the risk of low arterial pH, however, reflecting small differences in absolute numbers. Other outcomes were unchanged.

CONCLUSIONS: Overall, the MAMAACT intervention did not improve the composite perinatal mortality and morbidity outcome (when excluding NICU admissions). . The lack of effects may be due to contextual factors including organizational barriers in ANC hindering the midwives from changing practices.