# How Are Sleep, Settle, and Crying Behaviors in 2‐Month‐Olds Related to Concurrent Family Factors and Later Development?

## TL;DR

The study finds that 2-month-old infants' sleep and crying behaviors are linked to family income but not to later developmental issues in a general population sample.

## Contribution

This study identifies family income as a novel predictor of early infant regulatory behaviors in a large general population sample.

## Key findings

- Higher family income was associated with shorter crying duration and faster settling time in 2-month-old infants.
- Early sleep and crying behaviors did not predict later language, autistic traits, or hyperactivity in toddlerhood.
- Corrected age at assessment was significantly linked to fewer nighttime wakeups and shorter crying duration.

## Abstract

Sleep, settle, and crying behaviors represent basic regulatory functions in early infancy, yet little is known about the factors that influence these behaviors and their relationship to later development in the general population. In this study, we assessed a sample of 362 infants, measuring parent‐rated number of wakeups per night, time to settle, and crying duration at 2 months of corrected age (range 27–99 days), along with various background variables. We also measured several aspects of the infants’ later development at 14 and 24 months. Age (corrected) at the first assessment showed a significant association with number of wakeups per night (β = –0.212, p < 0.001) and crying duration (β = –0.154, p = 0.012). Family income was a significant predictor of crying duration (β = –0.128, p = 0.018) and time to settle (β = –0.147, p = 0.011). Sleep, settle, and crying behaviors at 2 months were not significantly associated with parent‐rated language comprehension or socio‐communicative abilities at 14 months, nor with vocabulary, autistic traits, or hyperactivity at 24 months. While some sleep and settle behaviors in the first few months can be challenging for caregivers, our findings suggest that they are not indicators of atypical development in early childhood in the general population.

In a sample of more than 350 infants, we found that higher family income was associated with shorter time until settled and shorter crying duration at 2 months of age.Sleep, settle, and crying behaviors at 2 months did not show statistically significant associations with language development, hyperactivity, or autistic traits in toddlerhood.

In a sample of more than 350 infants, we found that higher family income was associated with shorter time until settled and shorter crying duration at 2 months of age.

Sleep, settle, and crying behaviors at 2 months did not show statistically significant associations with language development, hyperactivity, or autistic traits in toddlerhood.