# Immediate skin-to-skin contact at very preterm birth and effect on infant socio-emotional stress response and mother–infant cortisol co-regulation: secondary outcomes from the randomised clinical Immediate Parent-Infant Skin-To-Skin Study (IPISTOSS)

## TL;DR

Immediate skin-to-skin contact after very preterm birth may improve infant emotional responses and mother-infant stress hormone coordination at 4 months.

## Contribution

Shows improved socio-emotional stress response and cortisol co-regulation from early skin-to-skin contact in preterm infants.

## Key findings

- iSSC infants showed higher positive emotionality during stress tests at 4 months.
- iSSC was linked to stronger mother-infant cortisol synchrony before and after stress exposure.
- 65 infants were assessed, with 37 providing cortisol samples for analysis.

## Abstract

To explore the effects of immediate parent–infant skin-to-skin contact (iSSC) at very preterm birth on maternal–infant behavioural responses and hypothalamic–pituitary–adrenal (HPA) axis reactivity to age-appropriate socio-emotional stress at 4 months corrected age.

Two secondary outcomes from a multicentre randomised controlled trial with two non-blinded parallel groups.

Three Scandinavian neonatal intensive care units, level 2 and level 3.

91 infants born at gestational age 28+0 to 32+6 from April 2018 to June 2021. Singletons and twins with a second caregiver present were included, regardless of mode of birth. Higher-order births, infants with congenital infections and major malformations were excluded.

Infants were randomised before birth to iSSC (n=46) or conventional care (n=45) during the first 6 hours of life. At 4 months corrected age, the infants were exposed to socio-emotional stress using the Face-to-Face Still-Face procedure (FFSF). Salivary cortisol was collected before and after FFSF.

Behavioural and hormonal stress responses at 4 months of age.

65 of 91 infants were assessed by FFSF, of which 37 infants had cortisol sampling. The iSSC group demonstrated heightened positive emotionality during FFSF compared with controls (beta 0.74, 95% CI 0.40 to 1.07; p<0.001). Also, the iSSC group showed an association between mother−infant cortisol levels at baseline (r 0.55, 95% CI 0.13 to 0.80; p=0.014) and 30 min post-FFSF (r 0.55, 95% CI 0.05 to 0.83; p=0.035).

Infants who experienced iSSC during the first 6 hours after very preterm birth showed improved infant socio-emotional stress coping and suggested enhanced mother–infant HPA axis synchrony at 4 months.