OBJECTIVES: The aim of this study was to investigate whether preterm infants whose 141 families have lower socioeconomic status (SES) or communicate with clinical staff in a language 142 other than English experience differences in the total amount, frequency, and duration of 143
Kangaroo Care (KC) compared to preterm infants of higher SES or primarily English-speaking 144 families. 145 146 METHODS: Participants were infants born <32 weeks gestational age (GA), N=116. We 147 defined family SES by the infants' health insurance (private/higher vs. public/lower) and family 148 language by the language mothers used to communicate with clinical staff (English vs. Other 149 language). Family SES or family language groups were compared on: (1) the total amount of 150 KC infants experienced during hospitalization;
(2) frequency of KC per visitation days; and, (3) 151 duration of KC events per day. 152 153 RESULTS: Infants in the lower SES and Other language groups experienced KC in reduced 154 amounts, lower frequencies, and shorter durations than infants in either the higher SES or 155
English language groups. SES and language group differences remained significant after 156 controlling for family visitation and GA at birth. After controlling for SES, language group 157 differences in KC duration remained significant. 158 159 CONCLUSIONS: Our findings revealed disparities in the total amount, frequency, and 160 duration of KC in the neonatal intensive care unit as a function of both family SES and language 161 families used to communicate with clinical staff. These disparities reduced infants' access to this 162 developmental care practice shown to stabilize clinical status and promote neurodevelopment. 163 We recommend that hospital nurseries implement policies that minimize such disparities. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this this version posted November 12, 2020. ; https://doi.org/10.1101/2020.11.09.20224766 doi: medRxiv preprint
Kangaroo Care (KC) is a developmental care practice that provides parent-to-infant skin-to-skin 176 contact 1,2 . This practice has been shown to reduce medical complications of preterm birth, such 177 as hypothermia, sepsis, and rehospitalization 1,2 . It has also been shown to promote infant 178 growth, breastfeeding, and mother-infant attachment 3 . Moreover, KC has been associated with 179 improved neurocognitive developmental outcomes, including better hearing, speech, social, and 180 executive function skills, in preterm infants and children 4,5 . All these benefits are crucial for 181 infants born very preterm (<32 weeks gestational age, GA), who are likely to encounter many 182 complications of prematurity that lead to early clinical instability, prolonged hospitalization, and 183 potentially long-term behavioral, cognitive, social-emotional, language, and learning delays 6-14 . 184
Developmental care practices have been adopted as a part of the standard of medical care in 185 many neonatal intensive care units (NICU) 15-19 to reduce preterm-birth-related morbidities, 186 support parent-infant bonding, and to possibly improve long-term developmental outcomes. 187
Despite the many apparent benefits of KC, however, several barriers may reduce opportunities 188 for such practice, including parental factors (e.g., rates of visitation, family comfort with the 189 practice) and health system factors (e.g., unit design, adequate staff support, parent educational 190 programs, access to translators) 3,20-28 . Parents and health care providers are also susceptible to 191 cultural norms and personal beliefs that affect the frequency and amount of KC 20 practice. In the present study, we investigated whether the family's SES and their preferred 207 language to communicate with clinical staff influenced the total amount, frequency, and duration 208 of KC with their preterm infants in the NICU. We hypothesized that infants whose families have 209 lower SES or communicate with clinical staff in a language other than English would receive 210 lower total amount, frequency, and duration of KC compared to infants whose families have 211 higher SES or speak English to clinical staff. These findings would have implications for 212 building policies and procedures to increase KC in the NICU for groups at increased risk for 213 adverse health and developmental outcomes. 214
Participants were infants born at a GA of less than 32 weeks, who were hospitalized at the Lucile 217 Packard Children Hospital (LPCH) in Stanford. From the electronic medical record (EMR), we 218 retrospectively acquired data on these infants' experience of KC from May 1, 2018, when 219 developmental care practices (including KC) at LPCH started being recorded consistently in the 220 7 EMR by clinical staff, to March 8 th , 2020, when LPCH changed visitation policies due to 221 COVID-19. These infants' data are part of a broader study investigating developmental care 222 practices in relation to brain development, and thus we collected the data from the date of birth 223 (DOB) until the infants' routine brain imaging session date (MRI) that occurs around 36 weeks 224 postmenstrual age. 225
The sample (N=116) was divided into two groups by each of the two key factors: family 226 SES and family language. For SES, we used the infant's health insurance as a proxy for this 227 factor. Private insurance was classified as higher SES and public insurance as lower SES (Table  228 1). For family language, we used a specific field in the EMR that indicated the language that 229 mothers used to communicate with clinical staff, specifically either English or another language 230 (e.g., Spanish, Mandarin, Dari), as a proxy for language primarily used by all family members 231 with clinical staff. For one participant, these data were missing (i.e., the language their mother 232 used to communicate with clinical staff), and thus we used the language reported for the father. 233
At LPCH, translators were available at all times for most common languages either via bedside 234 iPads or in-person interpreters during daytime hours. Of those families who used a language 235 other than English (n=34), 26 families used Spanish, the largest linguistic representation in the 236 study location that is not English. The protocols for this study were approved by the Stanford 237 University Institutional Review Board. 238
We extracted the following information about the participants to characterize the sample: sex, 240 GA at birth, days of hospitalization (from DOB to MRI), and race. We also extracted 241 information about infants' medical conditions, including clinical factors that may have reduced 242
infants' ability to receive KC or barriers to KC per policy in the LPCH NICU (e.g., necrotizing 243 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this this version posted November 12, 2020. ; enterocolitis, proportion of infants requiring high frequency oscillatory ventilator). To account 244 for parents' availability to perform KC, we determined the frequency of family visitation from 245 the EMR. At LPCH, parents were permitted to visit at any time of the day, except during 246 nursing sign out (7:00-7:30 a.m./p.m.). Daily visitation was counted as having occurred if 247 clinical staff charted that any family member engaged in KC with their infant or had visited at 248 bedside. We quantified the frequency of family visitation as the percentage of days that families 249 visited out of the total days an infant was hospitalized (from DOB to MRI). 250
The NICU at LPCH has standardized unit guidelines on developmental care activities to support 252 parent participation. KC done by any family member was recorded by clinical staff in the 253 infants' EMR. We derived the following three metrics from the KC data to assess: (1) KC total 254 amount, the total minutes infants experienced KC from DOB to MRI; (2) KC frequency, the 255 percentage of days that families performed KC out of the total number of days that families 256 visited the hospital (total KC days/total visitation days); and, (3) KC duration, the rate in minutes 257 per day of KC events (total KC minutes/total KC days). 258
We performed separate Chi square tests for each categorical variable and independent samples t-260 tests for each continuous variable to compare groups on demographic, clinical, and visitation 261 variables. For KC total amount, frequency, and duration, we performed separate analyses by 262 each group factor: family SES or family language. Since the metric KC total amount was 263 intrinsically biased by the variance in visitation days across infants, we performed a univariate 264 analysis of covariance (ANCOVA), controlling for family visitation. We also performed 265 separate univariate ANCOVA to control for demographic or clinical risk factors that were found 266 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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to differ between the groups. For KC frequency and duration metrics, we carried out separate 267 analysis of variance by family SES or family language. Also, we performed separate univariate 268 ANCOVA to control for each demographic or clinical risk factor that differed between the 269 groups. Threshold for significance was set at p < 0.05. All analyses were conducted using the Table 1 shows demographic, clinical, and family visitation variables of the sample divided by 276 family SES. The groups were balanced in all demographic variables but family language. The 277 lower SES group had a higher proportion of infants whose families used a language other than 278
English to communicate with clinical staff. The groups did not statistically differ on clinical 279 factors. The percentage of days infants in the lower SES group were visited by their families 280 was significantly lower compared to infants in the higher SES group. 281 Table 2 shows demographic, clinical, and family visitation variables of the sample 282 divided by family language. The groups were statistically balanced on all demographic variables 283 other than GA at birth and family SES; the Other language group had infants born at an older GA 284 and were predominantly from lower SES families. The groups did not statistically differ on 285 clinical factors. The percentage of days infants in the Other language group were visited by their 286 families was lower, although not statistically significant, relative to infants in the English group. 287
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The copyright holder for this this version posted November 12, 2020. ; https://doi.org/10.1101/2020.11.09.20224766 doi: medRxiv preprint Table 3 compares KC metrics between family SES groups. The total amount, frequency, and 289 duration of KC was significantly lower for infants in the lower SES group, as compared to the 290 higher SES group (Table 3 ; Figure 1 A-C). Between-group differences in the total amount of 291 KC remained significant after controlling for family visitation and either GA at birth or family 292 language. Group differences in frequency and duration of KC also remained significant after 293 controlling for GA at birth or family language. 294 Table 4 compares KC metrics between family language groups. The total amount, 295 frequency, and duration of KC was significantly lower for infants in the Other language, as 296 Consistent with our hypothesis, we found that KC, however measured, total amount during 305 hospitalization, frequency during visitation, and duration per day, was experienced less by 306 infants from lower SES families or whose families spoke a language other than English. These 307 results were significant after controlling for days of family visitation and for infants' GA at birth. 308 Disparities in KC found on the basis of family SES also remained significant after controlling for 309 family language. Disparities found on the basis of family language for KC duration, but not total 310 amount or frequency, remained significant after controlling for family SES. 311 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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The present study provides novel evidence that both family SES and family language 312 other than English are factors that contribute to significant disparities in the total amount, 313 frequency, and duration of KC experienced by preterm infants in the NICU. Importantly, we 314
show that disparities in KC were not solely explained by how frequently families visited the 315 hospital. These findings are generally consistent with previous studies that have examined the 316 contribution of socio-demographic factors to parental involvement in KC activities. For 317 example, a study reported that parental holding increases if mothers are White, married, older, or 318 employed compared to non-White, single, and younger parents 34 . Another study showed that 319 white mothers are told KC is an activity they could do with their infants 50% more often 320 compared to non-white mothers 35 non-English-speaking families in the present study may be at a further disadvantage in reaching 332 goal doses of this important developmental care practice, therefore raising further concern for the 333 outcomes of these already at-risk infants. 334 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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The copyright holder for this this version posted November 12, 2020. ; https://doi.org/10.1101/2020.11.09.20224766 doi: medRxiv preprint parents are seen as partners of the clinical staff 47,48 and which expect parents to be present for 358 longer periods and transition to active caregivers, thus potentially removing many barriers to 359 visitation and to KC 49 . In societies without social supports of extended parental leave and 360 childcare programs, these offered models are likely to have little impact on disparities between 361 groups 50 . More research is needed to understand the potential impact of family-centered care 362 programs on mitigating disparities, particularly in countries with fewer social programs to 363 support parents. This study has limitations. The data were extracted and analyzed from EMRs and may 397 thus capture inconsistencies in reporting from clinical staff. The sample was not large enough to 398 explore potential interactions between family SES and family language use. Our measures of 399 family SES and family language were limited. Finally, this investigation was a single-site study. 400
More studies are needed to further assess the barriers to KC in the NICU, specifically focused on 401 parents-clinical staff partnership quality. 402 403 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
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This investigation presents an in-depth analysis of KC for preterm infants in a NICU in the 405 United States in relation to their family's SES and language use in the hospital, revealing 406 significant and concerning disparities. We recommend rapid modifications of policies that guide 407 and promote this developmental care practice in the NICU and quality improvement studies to 408 assure rapid and effective quantitative changes. A common goal should be to reduce disparities 409 in KC, a critical early-life experience in this at-risk population. 410 All rights reserved. No reuse allowed without permission. preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this this version posted November 12, 2020. ; 10.73 <0.001 Abbreviations: GA = gestational age; M = mean; SEM = standard error of the mean; bold = significant. 