Background: Regulatory problems (excessive crying, feeding, and sleeping difficulties), specifically their comorbidity, are early warning signs of future problems. Insensitive parenting and neurodevelopmental vulnerabilities have been suggested as factors explaining development or maintenance of regulatory problems. Nevertheless, none of the previous studies investigated these factors within the same sample across infancy, taking into account the reciprocal influences between maternal sensitivity and regulatory problems.Aim: To investigate the prospective association between very preterm birth, comorbid regulatory problems and maternal sensitivity.Subjects: 178 participants including 73 very preterm/very low birth weight and 105 full-term infants and their caretakers.Study Design: A prospective study from birth to 18 months.Measures: Regulatory problems were measured at term, 3 months and 18 months with a structured parental interview. Maternal sensitivity was measured with a nurse observation at term; and a researcher observation of play tasks at 3 months and at 18 months.Results: Very preterm birth was associated with regulatory problems at term (β=0.19, SE= 0.10, p< 0.05) and at 18 months (β=0.21, SE= 0.10, p< 0.05), while it had no association to maternal sensitivity across infancy. There were no cross-lagged reciprocal effects between maternal sensitivity and regulatory problems across infancy. Maternal sensitivity at term had a negative association to regulatory problems at 3 months (β=-0.26, SE= 0.12, p< 0.05), but not from 3 to 18 months.Conclusions: Neurodevelopmental vulnerabilities provided more consistent prediction of regulatory problems in comparison to sensitive parenting.