Change in sex-specific gestational length-for-age z-score while admitted to the NICU.

Change in sex-specific gestational head circumference z-score while admitted to the NICU.

Experienced NEC during NICU stay according to Vermont Oxford Network (VON) definition; criteria: yes/no.

Experienced with LOS during NICU stay according to Vermont Oxford Network (VON) definition; criteria: yes/no.

Proportion of nursing shifts where mother is present in the NICU.

Score of mother-infant bonding assessed inspired by the Postpartum Bonding Questionnaire, where participants rate their agreement of statements on Likert scales ranging from 0 (always) to 5 (never); scores range from 0 to 50, with higher scores indicating more bonding challenges.

Milliliters of nursing shift-total enteral intake that is maternal breast milk fed via gavage tube or bottle.

Occurrence of direct breastfeeding episode during each nursing shift.

Score of self-reported Short Form Health Survey -1 Physical Health Item; assesses participants' perception of their current physical health. Lower score indicates worse perceived physical health.

Score of self-reported 10-item Perceived Stress Scale (PSS-10); assesses the perceived stress levels experienced in terms of overstrain, unmanageability, and unpredictability in the past month. Higher score indicates worse outcome.

Score of the Edinburgh Postnatal Depression Scale (EPDS), a 10-item self-report measure of postpartum depression (ranges from 0-30) with a higher score indicating worse depressive symptoms. The EPDS was developed to assist health professionals in detecting mothers suffering from postpartum depression (PPD).

Average response time across all trials to assess overall speed of responses. Lower scores indicate faster reaction times and better attentional performance.

Proportion of accurate responses on the ANT-R. Higher scores indicate higher accurate responses.

Average reaction time across trials, assessing overall speed and vigilance. Lower scores indicate quicker reaction times and heightened vigilance.

Percentage of correct responses out of the total number of trials on the Psychomotor Vigilance Task (PVT). Higher scores indicate higher accurate responses.

Score on Happiness Indicator from Integrated Values Surveys; assesses the overall and current perceived level of happiness experienced; with a 4-point scale from 0 (Not at all happy) to 3 (Very Happy). Higher score indicates better perceived level of happiness.

Score of the Life Satisfaction Scale Item; assesses participants' perception of their current overall life satisfaction; with a 4-point scale from 0 (Very Satisfied) to 3 (Not At All Satisfied), and was reverse-coded such that higher scores indicate better perceived life satisfaction.

Score of Sleep Quality Score (SQS) with 7-Day Recall; evaluates the overall quality of sleep. Core components include sleep duration, ease of falling asleep, frequency of waking during the night (excluding bathroom visits), early waking, and sleep refreshment. The respondent marks an integer score from 0 to 10, according to the following five categories: 0 = terrible, 1-3 = poor, 4-6 = fair, 7-9 = good, and 10 = excellent. Higher score indicates better perceived sleep quality.

Number of routine postpartum follow-up visits attended by mom.

Score of financial stress during the NICU stay based on two metrics: difficulty in paying bills and remaining money at the end of the week. Scoring for each question is summed to create an overall financial distress score, ranging from 0 to 8. Higher score indicates higher financial distress.

Score of financial hardships experienced during the NICU stay, including using up all savings, taking out loans, borrowing from friends, incurring debt, being threatened by eviction, or having a shut-off of an energy utility. Scoring for each question is yes/no and is summed to create an overall score that ranges between 0 and 6.

Score of Food Insecurity Screening Tool; assesses the risk of food insecurity (availability and affordability) in households based on questions derived from the U.S. Household Food Security Survey Module. Response options include: "Often True," "Sometimes True," "Never True". An affirmative response on either item will be considered to be positive for food insecurity.

Number of moves family has made since their child's birth.

Score on housing insecurity scale; assesses participants' worry that they may not have stable housing in the next 2 months. Likert scales ranging from 0 (not at all worried) to 3 (very worried). Higher scores indicate greater levels of housing insecurity.

Score on transportation insecurity item; assesses participants' experience of transportation-related issues affecting their ability to visit the NICU. Likert scales ranging from 0 (never) to 3 (always). Higher scores indicate greater levels of transportation insecurity.

The total number of days from infant admission to discharge from the hospital.

Any mother readmission to the hospital after her initial discharge.

Any infant readmission to the hospital after initial discharge.

The number of emergency department visits by the mother in the postpartum period.

The number of emergency department visits by the infant after discharge.

Mothers report of exclusive infant supine position to sleep in the last two weeks.

Mothers report exclusively using the room-sharing sleep method, where the infant sleeps in the same room as an adult but on a separate crib or sleep surface, without bed-sharing, in the last two weeks.

Mothers report of breastfeeding continuation.

Mothers report of knowledge about Skin-to-skin (STS) care based on 4 questions. Scored as a count variable that ranges between 0 and 4.

Mothers report of knowledge about breastfeeding based on 7 questions. Scored as a count variable that ranges between 0 and 7.

Assesses mothers' overall perception of hospital experience and hospital services during their stay, using a scale from 0 (worst hospital possible) to 10 (best hospital possible).

Composite score (0-100) based on four behavioral components: diet quality, physical activity, sleep health, and nicotine exposure, scored according to American Heart Association Life's Essential 8 criteria.

Number of visits with a primary care provider for routine or sick care.

Self-reported adherence to recommended postpartum care for chronic conditions (hypertension, diabetes, and mental health), including medication adherence and engagement with healthcare providers for condition management.