In the transition to parenthood, the COVID‐19 pandemic poses an additional strain on parental well‐being. Confirmed infections or having to quarantine, as well as public health measures negatively affect parents and infants. Contrary to previous studies mainly focusing on the well‐being of school‐aged children and their parents during lockdown periods, the present study investigated how mothers of infants respond to the COVID‐19 pandemic and whether this is related to maternal well‐being, maternal socio‐emotional investment, and infant regulation. Between April and June 2021, 206 mothers of infants ( M age = 7.14 months, SD age = 3.75 months) reported on COVID‐19 infections, their response to the COVID‐19 pandemic, their well‐being, socio‐emotional investment, and their infant’s regulation. Exploratory factor analyses yielded five dimensions of maternal response to the COVID‐19 pandemic: social distancing, worrying about the child, birth anxiety, distancing from the child, and information on COVID‐19‐related parenting behavior and support. These dimensions were related to mother‐reported infant regulatory problems. Path analyses revealed paths via reduced maternal well‐being and maternal socio‐emotional investment. Maternal perceptions of infant regulatory problems are related to how the mothers respond to the COVID‐19 pandemic. Better information about COVID‐19‐related parenting behavior and support might buffer against these effects.

The LEARN-COVID pilot study collected data on infants and their parents during the COVID-19 pandemic. Assessments took place between April and July 2021. Parents (N = 357) from Switzerland (predominantly), Germany, and Austria answered a baseline questionnaire on their behaviour related to the pandemic, social support, infant nutrition, and infant regulation. Subsequently, parents (n = 222) answered a 10day evening diary on infant nutrition, infant regulation, parental mood, and parental soothing behaviour. Data and documentation are stored on Zenodo, https://doi. org/10.5281/zenodo.6946048. These data may be valuable to researchers interested in infant development and parenting during the pandemic as well as to researchers interested in daily variability in infant behaviour, parenting, and nutrition.

Infant temperament is usually considered biologically driven and a precursor of personality. Despite being conceived as trait measures, parent reports for assessing infant temperament use short timescales, for example, the past 7 days, implying variability in temperament traits' expressions. In two daily diary studies, we use the perspective of whole-trait theory to investigate whether infant temperament is observable on a daily basis and to what degree infant temperament varies within-person across days. In Study 1, N = 137 mothers of infants aged 6-18 months reported on their infant’s daily (state) temperament (median number of days: 8, total observations: 984). The results suggest a substantial within-person variation in daily infant temperament (ICCs: .41 to .54). Study 2 (N = 199 mothers, median number of days: 7, total observations: 1375) replicated these results on the variability in infant state temperament (ICCs: .41 to .51). In addition, infant state temperament was related to infant trait temperament. However, certain temperament items – primarily those assessing surgency – were frequently rated as not applicable and did not seem suitable for daily assessments. Across both studies, results indicate substantial within-person variability in daily infant temperament and a strong trait component.