Neu 2010.

Methods	Randomized controlled trial carried out in Aurora, Colorado, United States
Participants	Number of infants: 60 Inclusion criteria: healthy infants with gestational age between 32 and 34 weeks, oxygen requirement < ½ liter O2 per nasal cannula, infant without umbilical lines, intraventricular hemorrhage, physical anomalies or anticipated major surgery, mother fluent in English or Spanish without recorded or stated illicit drug use, or diagnosis of serious chronic illness Exclusion criteria: unreported Infant stabilization status at trial entry: stabilized Infant age and weight at trial entry: Mean age at recruitment was 15.0 ± 6.7 and 15.0 ± 4.9 days, and mean birthweight was 1990 ± 450 and 1880 ± 340 g, for KMC and control infants, respectively
Interventions	KMC group: infant in SSC on mother's chest for 60 consecutive minutes at least once daily over 8 weeks (n = 31) Control group: infant wrapped in blanket and held in mother's arms for 60 consecutive minutes at least once daily over 8 weeks (n = 29) In both conditions, weekly home visits by an experienced registered nurse included encouragement to hold the infant, emotional support, and information about infant behavior and development. Other control group received brief social visits with no holding constraints and participated in all assessments. In the meta‐analysis, we excluded results from this last control group Level of care: initially at the hospital, then at home Human resources: nurses Criteria for infant discharge from the hospital: not applicable Scheme for follow‐up of infants after discharge: twice a week for 2 weeks, followed by weekly visits for 6 months
Outcomes	Mother‐infant interaction at 6 months' follow‐up and infant vitality during the neutral‐face period of the Still‐Face Procedure
Notes	No data on percentage of LBW infants who met eligibility criteria. Approximately 60% of mothers who were approached declined to be included in the study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer random number generator
Allocation concealment (selection bias)	Low risk	Opaque sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants: no/unfeasible; blinding of clinical staff: no/unfeasible
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Four researchers assessed outcome measures. Two outcome assessors were blinded to the hypotheses of the study but not to group assignment of mother‐infant dyads. The other 2 researchers were blinded to group assignment and hypotheses
Incomplete outcome data (attrition bias) All outcomes	High risk	87 infants were randomized: 31 to KMC, 29 to traditional holding, and 36 to control. At 6 months of age, 8 infants (9.2%) were lost to follow‐up and 14 (16.1%) were excluded (8 withdrawn for maternal reasons and 6 because of technical problems during videotaping)
Selective reporting (reporting bias)	Low risk	All outcomes stated in Methods section adequately reported or explained in Results
Other bias	Low risk	Other biases not identified