Effects of Light Exposure for Postpartum Depression on Infant Development

The Bayley Scale of Infant and Toddler Development - 4th Edition (BSITD-4; Bayley, 2019). Bayley Scale is recognized as a gold-standard tool for assessing child development and identifying developmental delays across five domains: cognitive, language, motor, social-emotional, and adaptive behavior (Bayley & Aylward, 2019). The cognitive, language, and motor domains involve structured activities administered to the child, with caregiver involvement as needed. The social-emotional and adaptive behavior domains are assessed via caregiver questionnaires. The BSITD-4 scoring is age-based, with a specific starting point for each domain. Raw scores are summed and scaled, and composite scores are calculated. Composite scores classify performance as: Very superior (>130), superior (120-129), high average (110-119), average (90-109), low average (80-89), borderline (70-79), or extremely Low (<69).

The Bayley Scale of Infant and Toddler Development - 4th Edition (BSITD-4; Bayley, 2019). Bayley Scale is recognized as a gold-standard tool for assessing child development and identifying developmental delays across five domains: cognitive, language, motor, social-emotional, and adaptive behavior (Bayley & Aylward, 2019). The cognitive, language, and motor domains involve structured activities administered to the child, with caregiver involvement as needed. The social-emotional and adaptive behavior domains are assessed via caregiver questionnaires. The BSITD-4 scoring is age-based, with a specific starting point for each domain. Raw scores are summed and scaled, and composite scores are calculated. Composite scores classify performance as: Very superior (>130), superior (120-129), high average (110-119), average (90-109), low average (80-89), borderline (70-79), or extremely Low (<69).

The Bayley Scale of Infant and Toddler Development - 4th Edition (BSITD-4; Bayley, 2019). Bayley Scale is recognized as a gold-standard tool for assessing child development and identifying developmental delays across five domains: cognitive, language, motor, social-emotional, and adaptive behavior (Bayley & Aylward, 2019). The cognitive, language, and motor domains involve structured activities administered to the child, with caregiver involvement as needed. The social-emotional and adaptive behavior domains are assessed via caregiver questionnaires. The BSITD-4 scoring is age-based, with a specific starting point for each domain. Raw scores are summed and scaled, and composite scores are calculated. Composite scores classify performance as: Very superior (>130), superior (120-129), high average (110-119), average (90-109), low average (80-89), borderline (70-79), or extremely Low (<69).

The Dimensional Inventory for the Assessment of Child Development (DIACD; Silva et al., 2019, 2020), developed and validated for Brazilian children (de Mendonça et al., 2021; Miranda et al., 2020; Silva et al., 2020), is a multidimensional parental proxy report to identify potential developmental delays in children aged 4 to 72 months. The inventory is organized in seven domains: Cognitive, Socioemotional, Receptive Language and Communication, Expressive Language and Communication, Gross Motor, Fine Motor, and Adaptive Behavior. The DIACD takes about 30 minutes. Analyses examining evidence of reliability found values ranging from 0.97 to 0.99 for responses across domains. The standardized score has a mean of 100 and a standard deviation of 15. Children are classified as well above age expectations (>130), above age expectations (123-130), typical development (85-116), risk of developmental delay (78-84), developmental delay (70-77), and significant developmental delay (<70).

The Dimensional Inventory for the Assessment of Child Development (DIACD; Silva et al., 2019, 2020), developed and validated for Brazilian children (de Mendonça et al., 2021; Miranda et al., 2020; Silva et al., 2020), is a multidimensional parental proxy report to identify potential developmental delays in children aged 4 to 72 months. The inventory is organized in seven domains: Cognitive, Socioemotional, Receptive Language and Communication, Expressive Language and Communication, Gross Motor, Fine Motor, and Adaptive Behavior. The DIACD takes about 30 minutes. Analyses examining evidence of reliability found values ranging from 0.97 to 0.99 for responses across domains. The standardized score has a mean of 100 and a standard deviation of 15. Children are classified as well above age expectations (>130), above age expectations (123-130), typical development (85-116), risk of developmental delay (78-84), developmental delay (70-77), and significant developmental delay (<70).

Infant weight, length, and head circumference, chest circumference, and body fat will be obtained by trained researchers during in-person visits, and the nutritional status will be calculated using the Anthro® software from the Brazilian Ministry of Health. Data will be collected in duplicate or triplicate by trained researchers using standardized protocols, with the average value recorded.

Infant weight, length, and head circumference, chest circumference, and body fat will be obtained by trained researchers during in-person visits, and the nutritional status will be calculated using the Anthro® software from the Brazilian Ministry of Health. Data will be collected in duplicate or triplicate by trained researchers using standardized protocols, with the average value recorded.

Infant weight, length, and head circumference, chest circumference, and body fat will be obtained by trained researchers during in-person visits, and the nutritional status will be calculated using the Anthro® software from the Brazilian Ministry of Health. Data will be collected in duplicate or triplicate by trained researchers using standardized protocols, with the average value recorded.

Mothers will also be assessed with respect to their beliefs, expectations, knowledge, and ability to breastfeed successfully. To address this goal, the Breastfeeding Self-Efficacy Scale (BSES; Dennis & Faux, 1999), validated for the Brazilian population (Oriá & Ximenes, 2010), will be used. The BSES is organized into four informational sources: personal experience, verbal persuasion, vicarious experience, and emotional/physiological state. The BSES is a self-administered questionnaire composed of 33 items rated on a 5-point Likert scale (range from strongly agree to "strongly disagree). Total scores (ranging from 33 to 165) are provided; higher scores reflect confidence in breastfeeding ability

Infant feeding practices measured by the Baby Eating Behavior Questionnaire (BEBQ: Lucion et al., 2017).) validated for the Brazilian population. This questionnaire examines specific appetite traits in children (ages 0 to 12 months), before the introduction of solid foods, within four domains: enjoyment of food, food responsiveness, speed of eating, and satiety responsiveness. The BEBQ is a self-administered instrument comprising 18 items and can be used regardless of breastfeeding type. Scale scores are the means of all scale items. Higher scores indicate more frequent demonstrations of behaviors characterizing the domain.

The Children's Eating Behavior Questionnaire (CEBQ; Wardle et al., 2001), validated for the Brazilian population (Viana, Sinde & Saxton, 2008), will be used to assess the eating behavior of children at 12 months; the mothers will complete the questionnaire. This is a self-administered instrument consisting of 35 items, in two dimensions: Food Avoidance assessed throughout four subscales (e.g., Satiety Responsiveness, Slowness in Eating, Food Fussiness, and Emotional Under-Eating) and Food Approach also assessed with four subscales (Food Responsiveness, Enjoyment of Food, Emotional Over-Eating, and Desire to Drink). Responses are provided on a 5-point Likert scale ranging from "never" to "always. Scale scores are the means of all scale items. Higher scores indicate more frequent demonstrations of behaviors characterizing the subscales.

The Brief Infant Sleep Questionnaire (BISQ; Sadeh, 2004) will be used to screen children sleep problems. The BISQ was developed in children aged 0 to 3 years. It is a semi-structured questionnaire consisting of 12 items related to the child's sleep in the past week, completed by parents or caregivers. It takes about 10 minutes to complete. Its validity and reliability were originally confirmed by comparisons with actigraphy and sleep diaries (Sadeh, 2004). The instrument was translated into Brazilian Portuguese by Nunes et al. (2012) and validated in a Brazilian study showing high specificity for sleep-related parameters, supporting parental reports for epidemiological research (Dal-Ponte et al., 2020). The criteria used to define poor sleepers based on the BISQ measures are as follows: 1) the child wakes > 3 times per night; 2) the nocturnal wakefulness period is > 1 hour; or 3) the total sleep time is < 9 hours.

The Brief Infant Sleep Questionnaire (BISQ; Sadeh, 2004) will be used to screen children sleep problems. The BISQ was developed in children aged 0 to 3 years. It is a semi-structured questionnaire consisting of 12 items related to the child's sleep in the past week, completed by parents or caregivers. It takes about 10 minutes to complete. Its validity and reliability were originally confirmed by comparisons with actigraphy and sleep diaries (Sadeh, 2004). The instrument was translated into Brazilian Portuguese by Nunes et al. (2012) and validated in a Brazilian study showing high specificity for sleep-related parameters, supporting parental reports for epidemiological research (Dal-Ponte et al., 2020). The criteria used to define poor sleepers based on the BISQ measures are as follows: 1) the child wakes > 3 times per night; 2) the nocturnal wakefulness period is > 1 hour; or 3) the total sleep time is < 9 hours.

The Dyadic Interaction Assessment Protocol (DIAP) is a bidirectional measure of adult-child interaction based on Ainsworth and Cox and validated in Brazil. It involves a standardized seven-minute free-play task in which caregiver-child behavior is coded across ten categories grouped into dyadic characteristics (child engagement with the environment, interaction with the caregiver, positive and negative affect, and caregiver sensitivity and intrusiveness) and adult characteristics (positive and negative affect, cognitive stimulation, and disengagement). The instrument demonstrates strong psychometric properties, including adequate interrater reliability, internal consistency, and convergent validity. Sessions follow the original free-play procedure with mother and infant, are video recorded with caregiver consent, coded by trained raters blinded to study variables using standardized guidelines, and disagreements are resolved by a third independent evaluator to ensure coding reliability

The Dyadic Interaction Assessment Protocol (DIAP) is a bidirectional measure of adult-child interaction based on Ainsworth and Cox and validated in Brazil. It involves a standardized seven-minute free-play task in which caregiver-child behavior is coded across ten categories grouped into dyadic characteristics (child engagement with the environment, interaction with the caregiver, positive and negative affect, and caregiver sensitivity and intrusiveness) and adult characteristics (positive and negative affect, cognitive stimulation, and disengagement). The instrument demonstrates strong psychometric properties, including adequate interrater reliability, internal consistency, and convergent validity. Sessions follow the original free-play procedure with mother and infant, are video recorded with caregiver consent, coded by trained raters blinded to study variables using standardized guidelines, and disagreements are resolved by a third independent evaluator to ensure coding reliability

The Interaction Rating Scale (IRS) assesses caregiver-child interaction in children aged 0-8 years through a structured five-minute observation. It comprises 70 dichotomous behavioral items and 11 impression items rated on a five-point scale, organized into ten factors representing child skills (autonomy, responsiveness, empathy, motor and emotional regulation) and caregiver behaviors (respect for autonomy, responsiveness, empathy, and cognitive and socioemotional support). A total score summarizes overall interaction quality. The IRS is currently undergoing validation in Brazil and, in its original version, demonstrated high interrater reliability and adequate to strong internal consistency. In this study, coding will rely on seven-minute free-play videos, be conducted independently by two trained raters, and discrepancies will be resolved by a third evaluator following standardized training procedures to ensure reliability.

The Interaction Rating Scale (IRS) assesses caregiver-child interaction in children aged 0-8 years through a structured five-minute observation. It comprises 70 dichotomous behavioral items and 11 impression items rated on a five-point scale, organized into ten factors representing child skills (autonomy, responsiveness, empathy, motor and emotional regulation) and caregiver behaviors (respect for autonomy, responsiveness, empathy, and cognitive and socioemotional support). A total score summarizes overall interaction quality. The IRS is currently undergoing validation in Brazil and, in its original version, demonstrated high interrater reliability and adequate to strong internal consistency. In this study, coding will rely on seven-minute free-play videos, be conducted independently by two trained raters, and discrepancies will be resolved by a third evaluator following standardized training procedures to ensure reliability.

A Portuguese-adapted version of the questionnaire from the survey Zero to Eight: Children's Media Use in America (Common Sense Media, 2013) will be used. This instrument includes questions regarding the types of media used by both children and caregivers, as well as the duration and frequency of use. The research team at Common Sense Media approved the translation of the questionnaire. For the present study, additional adaptations will be made to better capture the use of specific screens in families with infants aged 0 to 12 months.

A Portuguese-adapted version of the questionnaire from the survey Zero to Eight: Children's Media Use in America (Common Sense Media, 2013) will be used. This instrument includes questions regarding the types of media used by both children and caregivers, as well as the duration and frequency of use. The research team at Common Sense Media approved the translation of the questionnaire. For the present study, additional adaptations will be made to better capture the use of specific screens in families with infants aged 0 to 12 months.

The Hammersmith Neonatal Neurological Examination (HNNE: Correr & Pfeifer, 2023), validated for Brazilian infants, is an objective measure, will be administered at the 1-2 months of infant life in its extended forms. The HNEE extended version consists of 34 items across six domains: (1) posture and tone, (2) tone patterns, (3) reflexes, (4) movements, (5) abnormal signs, and (6) orientation and behavior. The examination takes about 15 minutes, and each item is scored as 0.0 (abnormal), 0.5 (intermediate), or 1.0 (normal). The total score is the sum of individual items, with normality ranging from 30.5 to 34 points. A borderline score does not necessarily indicate neurological issues but suggests the need for regular follow-up. It will be conducted by a trained professional with more than 10 years of experience in infant assessment. This measure will be used as a baseline to control for subsequent outcome measures.

Maternal dietary quality will also be assessed using the Food Intake Markers Questionnaire from the Food and Nutrition Surveillance System (FIMQ-SISVAN). This instrument is integrated into Brazil's public health system, and it is recognized for being practical and effective (Brazil, 2015; Louzada et al., 2023). The questionnaire will be administered at all five evaluation time points.

Maternal dietary quality will also be assessed using the Food Intake Markers Questionnaire from the Food and Nutrition Surveillance System (FIMQ-SISVAN). This instrument is integrated into Brazil's public health system, and it is recognized for being practical and effective (Brazil, 2015; Louzada et al., 2023). The questionnaire will be administered at all five evaluation time points.

Maternal dietary quality will also be assessed using the Food Intake Markers Questionnaire from the Food and Nutrition Surveillance System (FIMQ-SISVAN). This instrument is integrated into Brazil's public health system, and it is recognized for being practical and effective (Brazil, 2015; Louzada et al., 2023). The questionnaire will be administered at all five evaluation time points.

Maternal dietary quality will also be assessed using the Food Intake Markers Questionnaire from the Food and Nutrition Surveillance System (FIMQ-SISVAN). This instrument is integrated into Brazil's public health system, and it is recognized for being practical and effective (Brazil, 2015; Louzada et al., 2023). The questionnaire will be administered at all five evaluation time points.

Maternal dietary quality will also be assessed using the Food Intake Markers Questionnaire from the Food and Nutrition Surveillance System (FIMQ-SISVAN). This instrument is integrated into Brazil's public health system, and it is recognized for being practical and effective (Brazil, 2015; Louzada et al., 2023). The questionnaire will be administered at all five evaluation time points.

Maternal eating behavior will be assessed using the Three Factor Eating Questionnaire - R21 (TFEQ-R21) (Stunkard & Messick, 1985), validated for the Brazilian population (Natacci & Ferreira Júnior, 2011; Medeiros et al., 2017). The TFEQ-R21 is a self-report instrument consisting of 21 questions across three scales - Cognitive Restraint, Emotional Eating, and Uncontrolled Eating. Responses will be provided in a scored on a four-point Likert scale ("definitely false", "mostly false", "mostly true" and "definitely true") and an eight-point numerical rating scale. Scale scores will be calculated as the mean of the items within each domain, transformed into a scale from 0 to 100 to allow for direct comparison.

This scale was developed from the Medical Outcomes Study Social Support Survey (MOS-SSS) (Sherbourne & Stewart, 1991) with the aim of assessing social support in a multidimensional manner. It consists of 19 self-report items rated on a 5-point Likert scale, designed to assess how often the participant perceives having support from others in various situations. The items are distributed across five dimensions: tangible support, affectionate support, emotional support, informational support, and positive social interaction. The authors reported Cronbach's alpha coefficients greater than 0.91 for all dimensions (Sherbourne & Stewart, 1991). In the Brazilian translation and validation, internal consistency was high, with Cronbach's alpha coefficients ranging from 0.76 to 0.95 (Griep et al., 2005; Zanini & Peixoto, 2018).

This scale was developed from the Medical Outcomes Study Social Support Survey (MOS-SSS) (Sherbourne & Stewart, 1991) with the aim of assessing social support in a multidimensional manner. It consists of 19 self-report items rated on a 5-point Likert scale, designed to assess how often the participant perceives having support from others in various situations. The items are distributed across five dimensions: tangible support, affectionate support, emotional support, informational support, and positive social interaction. The authors reported Cronbach's alpha coefficients greater than 0.91 for all dimensions (Sherbourne & Stewart, 1991). In the Brazilian translation and validation, internal consistency was high, with Cronbach's alpha coefficients ranging from 0.76 to 0.95 (Griep et al., 2005; Zanini & Peixoto, 2018).