Breastfeeding is related to atypical autonomic and behavior regulation in infants with a history of excessive crying.

The study investigated autonomic regulation during feeding in six-month old infants with a history of excessive crying (EC) and social-behavioral development at 12 and 24 months. When contrasted with non-EC infants (NEC), EC infants had atypical autonomic responses observed as dampened reductions in respiratory sinus arrhythmia (RSA) and decreases in heart period (HP) during feeding. EC infants demonstrated atypical autonomic regulation only if they were bottle-fed, while breastfed EC infants had patterns of autonomic regulation similar to NEC infants. Behavioral data suggest that while a history of EC was related to social-emotional behaviors at 12 and 24 months, breastfeeding may buffer the behavioral effects of EC on sociability at 24 months.