[Articles] Clinical effectiveness of the Circle of Security-Parenting group intervention for birthing parents in perinatal mental health services in England (COSI): a pragmatic, multicentre, assessor-masked, randomised controlled trial

COS-P plus treatment-as-usual did not demonstrate greater clinical effectiveness compared with treatment-as-usual alone when delivered in NHS community perinatal mental health services. Therefore, COS-P should not be recommended for inclusion in routine community perinatal mental health services care, as it does not provide any additional clinical benefit when added to the current treatment-as-usual available in improving parental psychopathology, parenting, or infant outcomes.