Co-bedding between preterm twins attenuates stress response after heel lance: results of a randomized trial

Clin J Pain. 2014 Jul;30(7):598-604. doi: 10.1097/AJP.0000000000000015.


Objective: To examine the effect of co-bedding between preterm twins on stress response after heel lance.

Methods: Using a multisite randomized controlled trial design, stable preterm twins (67 sets, N=134 infants) between 28 and 36 completed weeks' gestational age, stratified by gestational age (≤ and >32 weeks) and site, were randomly assigned to a co-bedding group, cared for continuously in the same incubator or crib or a standard care group, cared for in a separate incubator or crib, and underwent a medically indicated heel lance after at least 24 hours and no greater than 10 days of group allocation. The reported outcome was cortisol from saliva samples from 89 twins (n=49 co-bedding, n=40 standard care) collected immediately before the heel lance (baseline levels) and 113 twins (n=58 co-bedding, n=55 standard care) collected 20 minutes after heel lance (stress levels) as an index of stress response.

Results: No group differences were noted in baseline salivary cortisol levels: 0.36 μg/dL (SD 0.25) in the co-bedding group and 0.43 μg/dL (SD 0.50) in the standard care group. Twenty minutes after lance, levels were significantly lower in the co-bedding group, 0.28 μg/dL (SD 0.25) versus 0.50 μg/dL (SD 0.73) in the standard group (P=0.04). Similarly, the mean of paired changes in salivary cortisol from baseline was lower in the co-bedding group (-0.06 μg/dL) compared with the standard care group (0.14 μg/dL, P<0.05).

Discussion: Co-bedding attenuates the stress response of preterm twins undergoing heel lance.

Trial registration: Identifier: NCT009176.

Trial registration: NCT00917631.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Twin Study

MeSH terms

  • Blood Specimen Collection / adverse effects*
  • Female
  • Gestational Age
  • Heel*
  • Humans
  • Hydrocortisone / metabolism
  • Infant
  • Infant Care*
  • Male
  • Premature Birth / blood*
  • Retrospective Studies
  • Saliva / metabolism
  • Statistics, Nonparametric
  • Stress, Psychological / etiology*
  • Stress, Psychological / metabolism
  • Stress, Psychological / nursing*


  • Hydrocortisone

Associated data