In an updated search to December 2002 five new studies were identified, but they did not meet the eligibility criteria for inclusion in this review. One study (Roberts 2000), classified as Awaiting Assessment in the existing review, was also found to be not eligible. This update incorporates data on psychomotor development at one year for the included study Charpak 1997.
The conclusion remains unchanged: there is still insufficient evidence from randomized trials to recommend the routine use of KMC in LBW infants.
Not enough evidence that kangaroo mother care is an effective alternative to standard care for low birthweight babies.
Low birthweight (less than 2500g) has an adverse effect on child survival
and development. Care of low birthweight babies is expensive and requires
specialist care. Kangaroo mother care (KMC) involves skin to skin contact
between mother and her newborn, frequent and exclusive or nearly exclusive
breastfeeding and early discharge from hospital. Compared with conventional
care, KMC was found to reduce severe illness, infection, breastfeeding problems,
and maternal dissatisfaction with method of care and improve some outcomes
of mother-baby bonding. There was no difference in infant mortality. However,
serious concerns about the methodological quality of the included trials
weaken credibility in these findings. More research
is needed.
In 1978, Rey and Martínez (Rey 1983) proposed and developed kangaroo mother care (KMC) at Instituto Materno Infantil in Santa Fe de Bogotá, Colombia, as an alternative to the conventional contemporary method of care for LBW infants. The term KMC is derived from similarities to marsupial caregiving. The mothers are used as "incubators" and as the main source of food and stimulation for LBW infants while they mature enough to face extrauterine life in similar conditions as those born at term. The method is applied only after the LBW infant has stabilized and all LBW infants need a variable period of conventional care before being eligible for KMC. The major components of KMC are: (1) skin-to-skin contact. Babies are kept, day and night, between the mother's breasts firmly attached to the chest in an upright position, (2) frequent and exclusive or nearly exclusive breast feeding, and (3) early discharge from hospital regardless of weight or gestational age. Respiratory, thermal and feeding stabilization are crucial for the success of this intervention. The definition of stabilization is not precise, and has been defined as independent of gestational age and weight, which are the main variables associated with those vital functions.
Different modalities of KMC have been adopted around the world (Charpak 1996) according to the needs of the settings. This diversity includes exclusive and non exclusive breastfeeding, breast or gavage feedings, completely or partially naked and with variable duration of exposure (1-24 hours/day), early-or-not hospital discharge.
KMC has been reported to be associated with similar neonatal mortality after stabilization, some reduction of neonatal morbidity, greater quality of mother to child bonding and lower hospital stay and costs compared with standard, conventional care of LBW infants.
This review covered all the randomized controlled trials of so called "kangaroo mother care" with all its components irrespective of duration of intervention, combination with co-interventions, and time at discharge from hospital. Skin-to-skin contact only, one of the components of KMC, is the subject of a separate review.
a) mortality
b) severe illness
c) infant growth
d) Psychomotor development
2. Secondary outcomes
a) infection
b) moderate illness
c) mild illness
d) admission to neonatal intensive care unit (NICU)
e) breastfeeding at discharge
f) length of hospital stay
g) readmission to hospital after discharge.
h) costs of care
i) parent satisfaction
j) staff satisfaction
k) any other clinically relevant outcomes
INCLUSION OF STUDIES
Each reviewer applied inclusion criteria separately. There were no disagreements among the reviewers about inclusion of studies. All trials excluded from the review were given reasons for exclusion.
METHODOLOGICAL QUALITY
An assessment of the quality of the included studies was performed independently
by two reviewers (ACA and JLDR). The methodological criteria used to appraise
each paper were concealment of treatment allocation, completeness of follow-up,
and blinding of assessment of outcome.
Quality scores for concealment of allocation were assigned to each trial,
using the criteria described in Section VI of the Cochrane Handbook.
(A) adequate
(B) unclear
(C) inadequate
(D) not used
In addition, quality scores for completeness of follow-up and blinding
of outcome assessments were assigned to each trial using the following criteria:
Completeness of follow-up:
(a) <3% of participants excluded
(b) 3% to 9.9% of participants excluded
(c) 10% to 19.9% of participants excluded
(d) 20% or more of participants excluded
For blinding of outcome assessment:
(a) blind, the investigator in charge of outcome evaluation did not know
the allocated treatment.
(b) no blinding, the investigator in charge of outcome evaluation knew
or was likely to
guess the allocated treatment.
(c) unclear.
Each paper was graded independently by the two reviewers. Differences among reviewers about quality scores were resolved by discussion and consensus was reached. Methodological assessments were not conducted blind to author, institution, journal of publication or results, as the reviewers were familiar with most of the studies.
DATA EXTRACTION
Data were extracted from the included reports by the two reviewers independently and cross-checked. The following data were extracted for each trial: authors; year of publication; country; inclusion and exclusion criteria; mean weight and gestational age at birth and at entry by group; description of interventions; co-interventions; number randomized and analyzed; number and reason of withdrawals and outcomes. If different periods or times of measurement were recorded, each was treated as a different outcome. Differences among reviewers in data extracted were resolved by discussion and consensus was reached. Additional information was sought from the individual investigators where the published information did not contain the required detail.
STATISTICAL ANALYSIS
The statistical package (RevMan 4.1) provided by the Cochrane Collaboration was used. Categorical data were compared using relative risks and their 95% confidence intervals. Continuous data were pooled using weighted mean difference and 95% confidence intervals. Where possible, data were sought to allow an "intention-to-treat analysis".
Eligibility for study group assignment was reached at a mean or median
(range) age of 13 (0-70) days in the Ecuadorian study (Sloan 1994), 8-10 (1-74) days in the Multicentred
study (Cattaneo 1998), and 3-4 (1-60) days
in the Colombian study (Charpak 1997).
The mean (SD) weight in grams for the infants at enrolment were 1678 ±
226 (KMC group) and 1715 ± 228 (control group) in the Colombian study
(Charpak 1997), 1584 ± 223 (KMC group)
and 1574 ± 251 (control group) in the Multicentred study (Cattaneo
1998), and 1704 ± 243 (KMC group) and 1704 ± 248 (control
group) in the Ecuadorian study (Sloan 1994).
Details of each study are given in the Table of "Characteristics of included
studies".
CHARPAK 1997
Concealment of allocation: (b) ; unclear
Completeness of follow-up: (c) ; 4% infants excluded. 67 (8.6%) infants
lost to follow-up although mortality data were available in 30 of these.
Blinding of outcome assessment: (b) ; those who collected the outcome measures
knew or were likely to guess the allocated treatment.
CATTANEO 1998
Concealment of allocation: (b) ; unclear.
Completeness of follow-up: Unclear. 38% of eligible infants were excluded.
It is not clear how many exclusions occurred after randomization.
Blinding of outcome assessment: (b) ; those who collected the outcome measures
knew or were likely to guess the allocated treatment.
All reports failed to provide complete outcome data for all those originally enrolled. Thus, it was not possible to perform intent-to-treat analyses on any outcome. No trial described procedures of allocation concealment. None of the trials reported any effort to reduce response bias, through use of an interviewer blinded to the infant's group allocation. However, it is hard to know if it would be feasible to blind clinicians to treatment allocation in a trial of KMC in LBW infants. In summary, the trials were of moderate to poor methodological quality.
Although conventional care implies promotion of breast feeding and facilitation and promotion of maternal involvement in the care of the neonate, which are critical for the outcomes measured, there was insufficient information on these variables in the control groups.
A strict definition of stabilization was not provided and this may affect external validity, because the timing of the intervention may be critical for its safety. The more immature the infant, the riskier it may be to apply the intervention under varying definitions of stabilization.
All but one of the results (not exclusively breastfeeding at 1 month follow-up) are based on data contributed by only one trial.
MORTALITY
No differences were seen in infant mortality assessed from eligibility
to 41 weeks' corrected gestational age, to discharge, at 6 month follow-up,
or at 12 months' corrected age.
INFECTION / ILLNESS
KMC was associated with a reduced risk of nosocomial infection at 41 weeks'
corrected gestational age (relative risk 0.49, 95% confidence interval 0.25
to 0.93), severe illness (relative risk 0.30, 95% confidence interval 0.14
to 0.67) and lower respiratory tract disease (relative risk 0.37, 95% confidence
interval 0.15 to 0.89) at 6 months follow-up. There was no evidence of a
difference in severe infection at 41 weeks' corrected gestational age or
at 12 months' corrected age, diarrhea, or mild or moderate illness at 6 months
follow-up.
FAILURE TO ESTABLISH BREASTFEEDING
KMC reduced the likelihood of not exclusively breastfeeding at discharge
(relative risk 0.41, 95% confidence interval 0.25 to 0.68). No differences
were seen in exclusive breastfeeding at 41 weeks' corrected gestational
age, at 1 or 6 months follow-up, or at 12 months' corrected age.
RE-ADMISSION TO HOSPITAL
There was no evidence of a difference in re-admission to hospital at 41
weeks' corrected gestational age, or at 6 months follow-up.
GROWTH
KMC infants had gained more weight per day by discharge than controls (weighted
mean difference 3.6 g/day, 95% confidence interval 0.8 to 6.4) and had a
larger head circumference at 6 months' corrected age than controls (weighted
mean difference 0.34 cm, 95% confidence interval 0.11 to 0.57) although these
differences are of low clinical significance. Sloan 1994 reported "there
were no significant differences between the groups in growth indices during
the 6-month follow-up". No differences were seen in weight, length, or head
circumference at 41 weeks' corrected gestational age or at 12 months' corrected
age or in weight at discharge.
PSYCHOMOTOR DEVELOPMENT
There were no differences in Griffith quotients for psychomotor development
at 12 months' corrected age.
PARENTAL DISSATISFACTION
KMC reduced the likelihood of maternal dissatisfaction with method of care
(relative risk 0.41, 95% confidence interval 0.22 to 0.75). There was no
evidence of a difference in paternal or family satisfaction with method of
care.
MOTHER'S ATTACHMENT BEHAVIOR
Based on the bonding hypothesis, a secondary publication of the Charpak 1997 trial reported results about mother's
attachment behavior. Two series of outcomes were assessed as manifestations
of mother's attachment behavior. The first was the mother's feelings and
perceptions of her premature birth experience, measured through a "mother's
perception of premature birth questionnaire" using a Likert scale (1 to 5),
24 hours after birth and when the infant reached 41 weeks' gestational age.
The second outcome was derived from observations made of the mother and child's
responsiveness to each other during breastfeeding, using a "nursing child
assessment feeding scale".
Overall scores on mother's sense of competence according to infant stay
in hospital and admission to NICU were better in KMC than in control group
(weighted mean differences 0.31 [95% confidence interval 0.13 to 0.50] and
0.28 [95% confidence intervals 0.11 to 0.46], respectively). On the other
hand, overall scores on mother's perception of social support according to
infant stay in NICU were worse in KMC group than in control group (weighted
mean difference -0.18, 95% confidence interval -0.35 to -0.01). There were
no differences in scores on mother's perception of social support according
to infant stay in hospital and mother's feelings of worry and stress, mother's
sensitivity, mother's responses to child's distress and socioemotional and
cognitive growth fostering, and infant's response to the mother (clarity of
cues and responsiveness) according to infant stay in hospital and admission
to NICU .
OTHER RESULTS
One trial provided information about episodes of both hypothermia and hyperthermia
which were significantly more frequent in control than in KMC infants (Cattaneo 1998). However, the data published
on these outcomes did not allow their inclusion in the tables.
The mean hospital stay from randomization to 41 weeks' corrected gestational
age was 4.5 days for KMC infants and 5.6 for control infants in the Charpak 1997 study. The maximum saving in hospital
stay was observed in infants weighing <1501 g at birth. No standard deviations
were provided. Cattaneo 1998 only reported median hospital stay, which was
11 days in the KMC group, compared to 13 days in the control group. Length
of hospital stay was two days greater in KMC infants than control infants
in the Sloan 1994 study.
The overall costs were "about 50% less for KMC" in the Cattaneo 1998 study.
In the Sloan 1994 study, "costs of neonatal care were greater in the control
than in the KMC group". However, data were available for only 49 infants
(24 KMC, 25 control) at 6-month follow-up. No information on mean (standard
deviation) costs were available in any of the trials.
Planned subgroup analyses according to birthweight, gestational age and type of LBW, and sensitivity analysis according to methodological quality of trials and methods of meta-analysis, were not made due to the small number of trials contributing data and to the lack of data.
No trial provided detailed information with regard to costs, an important outcome of this intervention. Most of the high cost of effective neonatal care from birth until discharge will continue to be necessary due to the need of technology and resources to increase survival until stabilization occurs and infants become eligible for KMC.
There has been no long term follow-up of developmental outcome of infants beyond 12 months corrected age in any of the trials to date.
| Study | Methods | Participants | Interventions | Outcomes | Notes | Allocation concealment |
| Cattaneo 1998 | Multicentred, 3 hospitals in Addis Ababa (Ethiopia), Yogyakarta
(Indonesia) and Merida (Mexico). Allocation by means of a random numbers list. 178 (38%) of the 463 eligible infants were excluded. It is not clear how many exclusions occurred after randomization. |
Infants with birthweight between 1000 and 1999 g without gestational
age limits, no dependency on oxygen and/or i.v. fluids, ability (at least
partial) to feed, no visible major malformation, and mother present and
willing to collaborate. Unknown number of infants initially randomized to each group. |
Infants allocated to the KMC group were kept in close and continuous
skin-to skin contact, between the mother's breasts, naked except for a diaper
and a hat, covered across their backs with their mother's clothes, day and
night, including when the mother was asleep. The mother was occasionally
replaced by another person. Infants allocated to the control group were kept in a warm room in Addis Ababa, with open cribs and the possibility of rewarming in a bulb-heated cot, and in incubators in the other two hospitals. Skin-to-skin contact with their mothers was not allowed. |
Severe illness, hypothermia, hyperthermia, breast feeding, weight gain, neonatal death, acceptability to health workers, acceptability to mothers, and costs. | B | |
| Charpak 1997 | Single centre in Bogota, Colombia. Allocation by means of a random numbers list. Of 396 (KMC) and 381(control) infants enrolled, 14 and 17 were withdrawn due to pre-existing neurologic impairment or proof of intrauterine infection and excluded from analysis; follow-up at 40 to 41 weeks' corrected gestational age was incomplete for 33 vs 34 survivors infants, but mortality data were available in 30 of these, giving mortality data for 364 vs 345. | Infants with birthweights <2001 g, with a mother or a relative
able to understand and willing to follow the general program instructions.
Exclusion criteria: being referred to another institution, plans to leave Bogota in the near future, life-threatening or major malformations, early-detected major conditions arising from perinatal problems, and parental or family refusal to comply with the follow-up program or, for those assigned to the KMC group, refusal to comply with the specifics of the intervention. 777 infants were randomized, 396 to the KMC group and 381 to the control group. |
Infants allocated to the KMC group were kept 24 hours a day in
a strict upright position, in skin-to-skin contact firmly attached to the
mother's chest. Infants were breastfed regularly, although premature formula
supplements were administered if necessary. Infants were discharged as soon
as they overcame major adaptations to extrauterine life, received proper
treatment for infection or concomitant condition, sucked and swallowed properly,
and achieved a positive weight gain. Infants allocated to the control group were kept in an incubator until they were able to regulate temperature and were thriving. The parent's access to their babies was severely restricted. |
1. At 40 to 41 weeks' corrected gestational age: -Primary outcomes: Mortality and infant growth. -Secondary outcomes: Length of hospital stay, infection, breastfeeding, and mother's attachment behavior. 2. At 12 months corrected age: Psychomotor development |
Data on 488 (65%) mother-infant dyads on mother's attachment
behavior were published one year later. Clinical data on 693 (93%) infants on outcomes at one year were partially published in abstract only (data not included in analyses). Clarification from the authors is being sought regarding the total numbers reported for the KMC and control groups in some of the analyses reported by Tessier 1998. |
B |
| Sloan 1994 | Single Centre in Quito, Ecuador. Allocation by means of a random numbers list. 17 babies lost to follow-up (KMC 9, control 8) ; no exclusions. |
Singleton infants weighing less than 2000 g, with no serious congenital abnormalities or respiratory, metabolic, or infectious disease. Infants had to be stabilized for the 24 h before enrolment: temperature between 36.5 and 37.0 ºC; acceptable tolerance of food; and stable weight. 300 infants were randomized, 140 to the KMC group and 160 to the control group. | Infants allocated to the KMC group were kept in an upright position,
in skin-to-skin contact (diapers allowed) against the mother's breasts and
had frequent breastfeeding. Infants allocated to the control group stayed in an incubator or thermal crib and were breastfed at scheduled times. |
Severe illnesses (lower respiratory tract disorders, apnea, aspiration, pneumonia, septicemia, general infections), moderate illness (urinary infections), mild illnesses (upper respiratory tract disorders, dermatitis, jaundice, hip displacement), diarrhea, infant growth (weight, length, upper arm and head circumference), duration of hospital stay, re-admission, and costs of care. | Trial stopped early because a highly significant difference (p<0.005
at 6 months) in severe morbidity arose. No information about whether this
was a planned interim analysis. Additional data provided by Dr Nancy L. Sloan. |
B |
| Study | Reason for exclusion |
| Arandia 1993 | Non-randomized trial |
| Bergman 1994 | Non-randomized trial |
| Charpak 1994 | Non-randomized trial |
| Chwo 2002 | The main intervention KMC was intermittent skin-to-skin contact. Moreover, 20 out of 34 enrolled infants did not have LWB. This study should be considered in the skin-to-skin contact review. |
| Dala Sierra 1994 | Non-randomized trial |
| Feldman 2002 | Non-randomized trial |
| Kambarami 1998 | Allocation was by alternation (quasi-random), not a random. 74 (37 per group) infants were subjected to KMC or incubator care. Infants in the KMC group had higher mean daily weight gain, shorter stay in hospital, and better survival rates. |
| Legault 1995 | Non-randomized trial |
| Ohgi 2002 | Non-randomized trial |
| Ramanathan 2001 | The intervention (KMC) was a combination of skin-to-skin contact of at least 4 hours per day and warmer/incubator for the rest of the time. 28 infants were randomized to receive either KMC along with standard care, or standard care alone. Infants in the KMC group hade better weight gain after the first week of life, earlier hospital discharge, and higher exclusive breastfeeding rates. This study should be considered in the skin-to-skin contact review. |
| Roberts 2000 | The intervention (KMC) was only skin-to-skin contact. 30 infants were randomly assigned to KMC or conventional cudding care in which the contact was through normal clothing. There were no differences on weight gain, hospital stay, duration of breastfeeding, temperature, and parental stress and expectations. This study should be considered in the skin-to-skin contact review. |
Cattaneo A, Davanzo R, Worku B, Surjono A, Echeverria M, Bedri A, Haksari E, Osorno L, Gudetta B, Setyowireni D, Quintero S, Tamburlini G. Kangaroo mother care for low birthweight infants: a randomised controlled trial in different settings. Acta Paediatr 1998;87:976-85.
Charpak 1997 {published data only}
Charpak N, Ruiz JG, Figueroa Z, Tessier R et al. Kangaroo Mother Care (KMC): A method of protecting high-risk premature infants. In: Pediatric Academic Societies, Annual Meeting. New Orleans, LA, May 1-5, 1998.
* Charpak N, Ruiz-Pelaez JG, Figueroa de C. Z, Charpak Y. Kangaroo mother versus traditional care for newborn infants <2000 grams: a randomized controlled trial. Pediatrics 1997;100:682-8.
Charpak N, Ruiz-Pelaez JG, Figueroa de C.Z, Charpak Y. A randomized, controlled trial of kangaroo mother care: results of follow-up at 1 year of corrected age. Pediatrics 2001;108:1072-9..
Tessier R, Cristo M, Velez S, Giron M et al. Kangaroo mother and the bonding hypothesis. Pediatrics 1998;102:e17.
Sloan 1994 {published and unpublished data}
Sloan NL, Leon Camacho LW, Pinto Rojas E, Stern C, and Maternidad Isidro Ayora Study team. Kangaroo mother method: randomised controlled trial of an alternative method of care for stabilised low-birthweight infants. Lancet 1994;344:782-5.
Arandia R, Morales L. Programa Madre-Canguro [Program kangoroo mother]. Gac Med Boliv 1993;17:51-5.
Bergman 1994 {published data only}
Bergman NJ, Jurisoo LA. The "Kangaroo-method" for treating low birth weight babies in a developing country. Trop Doct 1994;24:57-60.
Charpak 1994 {published data only}
Charpak N, Ruiz-Pelaez JG, Charpak Y. Rey-Martinez Kangaroo Mother Program: An alternative way of caring for low birth weight infants? One year mortality in a two cohort study. Pediatrics 1994;94:804-10.
Chwo 2002 {published data only}
Chwo MJ, Anderson GC, Good M, Dowling DA, Shiau SH, Chu DM. A randomized controlled trial of early kangaroo care for preterm infants: effects on temperature, weight, behavior, and acuity. J Nurs Res 2002;10:129-42.
Dala Sierra 1994 {published data only}
Dala Sierra E, Pineda Barahona E, Banegas RM. Experiencia madre canguro [Kangaroo mother experience]. Rev Med Hondur 1994;62:43-6.
Feldman 2002 {published data only}
Feldman R, Eidelman AI, Sirota L, Weller A. Comparison of skin-to-skin (kangaroo) and traditional care: parenting outcomes and preterm infant development. Pediatrics 2002;110:16-26.
Kambarami 1998 {published data only}
Kambarami RA, Chidede O, Kowo DT. Kangaroo care versus incubator care in the management of well preterm infants. A pilot study. Ann Trop Paediatr 1998;18:81-6.
Legault 1995 {published data only}
Legault M, Goulet C. Comparison of kangaroo and traditional methods of removing preterm infants from incubators. J Obstet Gynecol Neonatal Nurs 1995;24:501-6.
Ohgi 2002 {published data only}
Ohgi S, Fukuda M, Moriuchi H, et al. Comparison of kangaroo care and standard care: behavioral organization, development, and temperament in healthy, low-birth-weight infants through 1 year. J Perinatol 2002;22:374-9.
Ramanathan 2001 {published data only}
Ramanathan K, Paul VK, Deorari AK, Taneja A, George G. Kangaroo mother care in very low birth weight infants. Indian J Pediatr 2001;68:1019-23.
Roberts 2000 {published data only}
Roberts KL, Paynter C, McEwan B. A comparison of kangaroo mother care and conventional cuddling care. Neonatal Netw 2000 2000;19:31-5.
* indicates the primary reference for the study
Barker DJ. The fetal and infant origins of disease. Eur J Clin Invest 1995;25:457-63.
Charpak N, Ruiz-Pelaez JG, Figueroa de Calume Z. Current knowledge of kangaroo mother intervention. Curr Opin Pediatr 1996;8:108-12.
Guyer B, MacDorman MF, Martin JA, Peters KD, Strobino DM. Annual summary of vital statistics 1997. Pediatrics 1998;102:1333-49.
Rey, Martinez H.. Manejo racional del niño prematuro [Rational management of the premature infant]. In: I Curso de medicina fetal y neonatal. Bogotá, Colombia. 1983:137-51.
World Health Organization. Essential newborn care. Report of a Technical Working Group, Trieste, 25-29 April 1994. Geneva: Maternal and Newborn Health/Safe Motherhood (WHO/FRH/MSM/96.13), 1996.
World Health Organization. The World Health Report 1998. Life in the 21st century: a vision for all. Geneva: World Health Organization, 1998.
Conde-Agudelo A, Diaz-Rossello JL, Belizan JM. Kangaroo mother care to reduce morbidity and mortality in low birthweight infants (Cochrane Review). In: The Cochrane Library, Issue 4, 2000. Oxford: Update Software.
| Comparison or outcome | Studies | Participants | Statistical method | Effect size |
|---|---|---|---|---|
| 01 Kangaroo mother care versus conventional neonatal care | ||||
| 01 Mortality | RR (fixed), 95% CI | Subtotals only | ||
| 02 Infection / Illness | RR (fixed), 95% CI | Subtotals only | ||
| 03 Failure to establish breastfeeding | RR (fixed), 95% CI | Subtotals only | ||
| 04 Re-admission to hospital | RR (fixed), 95% CI | Subtotals only | ||
| 05 Growth | WMD (fixed), 95% CI | Subtotals only | ||
| 06 Parental dissatisfaction | RR (fixed), 95% CI | Subtotals only | ||
| 07 Mother's sense of competence according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.31 [0.13, 0.50] |
| 08 Mother's sense of competence according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.28 [0.11, 0.46] |
| 09 Mother's feelings of worry and stress according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.11 [-0.06, 0.29] |
| 10 Mother's feelings of worry and stress according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.09 [-0.08, 0.27] |
| 11 Mother's perception of social support according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | -0.16 [-0.33, 0.02] |
| 12 Mother's perception of social support according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | -0.18 [-0.35, -0.01] |
| 13 Mother's sensitivity according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.02 [0.00, 0.04] |
| 14 Mother's sensitivity according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.02 [0.00, 0.04] |
| 15 Mother's response to child's distress according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.00 [-0.03, 0.02] |
| 16 Mother's response to child's distress according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | -0.01 [-0.03, 0.02] |
| 17 Mother's response to child's socioemotional growth fostering according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.01 [-0.02, 0.04] |
| 18 Mother's response to child's socioemotional growth fostering according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.01 [-0.02, 0.04] |
| 19 Mother's response to child's cognitive growth fostering according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.01 [-0.02, 0.05] |
| 20 Mother's response to child's cognitive growth fostering according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.02 [-0.02, 0.05] |
| 21 Infant's response to the mother (clarity of cues) according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.01 [-0.02, 0.04] |
| 22 Infant's response to the mother (clarity of cues) according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.01 [-0.01, 0.04] |
| 23 Infant's response to the mother (responsiveness) according to infant stay in hospital | 3 | 488 | WMD (fixed), 95% CI | 0.02 [0.00, 0.04] |
| 24 Infant's response to the mother (responsiveness) according to infant stay in NICU | 2 | 488 | WMD (fixed), 95% CI | 0.02 [-0.01, 0.04] |
| 25 Psychomotor development (Griffith quotients) at 12 months' corrected age - Locomotion | 1 | 579 | WMD (fixed), 95% CI | 2.25 [-0.45, 4.95] |
| 26 Psychomotor development (Griffith quotients) at 12 months' corrected age - Personal, social | 1 | 579 | WMD (fixed), 95% CI | 0.97 [-1.27, 3.21] |
| 27 Psychomotor development (Griffith quotients) at 12 months' corrected age - Hand-eye coordination | 1 | 579 | WMD (fixed), 95% CI | 0.57 [-1.25, 2.39] |
| 28 Psychomotor development (Griffith quotients) at 12 months' corrected age - Audition-language | 1 | 579 | WMD (fixed), 95% CI | 1.29 [-0.98, 3.56] |
| 29 Psychomotor development (Griffith quotients) at 12 months' corrected age - Execution | 1 | 579 | WMD (fixed), 95% CI | 0.30 [-1.50, 2.10] |
| 30 Psychomotor development (Griffith quotients) at 12 months' corrected age - All criteria | 1 | 579 | WMD (fixed), 95% CI | 1.05 [-0.75, 2.85] |