Background It is still uncertain if osteopathic manipulative treatment improves preterm clinical outcomes.

Methods The present multi-centre randomised single blind parallel group clinical trial enrolled newborns who met the criteria for gestational age between 29 and 37 weeks without any congenital complication from 3 different public neonatal intensive care units. Preterm infants were randomly assigned to usual prenatal care (control group) or osteopathic manipulative treatment (study group). The primary outcome was the mean difference in length of stay between groups.

Results A total of 695 newborns were randomly assigned to the study group (n = 352) and to the control group (n = 343). A statistical significant difference was observed between the two groups for the primary outcome (13.8 and 17.5 days for the study and control group respectively, p < 0.001, effect size: 0.31). Multivariate analysis showed a reduction of the length of stay of 3.9 days (-5.5 to -2.3, p < 0.001). Furthermore, there were significant reductions with treatment as compared to usual care in cost (difference between study and control group: 1,586.01€; 1,087.18 to 6,277.28; p < 0.001) but not in daily weight gain. The relative risk of developing any respiratory problem during the study period was 0.53 (0.42 to 0.64). Moreover, the estimated research period attributable risk was 47%. There were no complications associated to the intervention.

Conclusions Osteopathic treatment reduced significantly the number of days of hospitalisation and costs on a large cohort of preterm infants.