Natural Variations in Maternal and Paternal Care are Associated with Systematic Changes in Oxytocin Following Parent-Infant Contact

Oxytocin levels rise in both mothers and fathers who provide high levels of affectionate touch but not in parents who provide less nurturing touch.

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Sample

  • N: 112 parents: 71 mothers, 41 fathers (not couples)
  • Subject Ages: Parents of infants ages 4 to 6 months
  • Location: Canada
  • SES: Middle class
  • Eligibility: Healthy parents and children
  • Additional:
    • All parents completed at least 12 years of education
    • Mothers average age 28.7 years, completed 15.7 years of education
    • 81.3% were breastfeeding
    • Fathers average age 29.1 years, completed 15.5 years of education
    • Infants were born full-term, 96.3% were vaginal deliveries, average Apgar scores of 9.4

Hypotheses

  1. There will be no difference in the baseline levels of plasma and salivary oxytocin (OT) in mothers and fathers during the first months of parenting.
  2. Mothers who provide high levels of affectionate contact, but not those showing low levels, will show an increase in OT levels following mother-infant contact.
  3. Fathers who provide high levels of affectionate contact, but not those showing low levels, will show an increase in OT level following father-infant contact.

Variables Measured, Instruments Used

  • Oxytocin - ELISA kit
  • Parent affectionate contact - the Coding of Parent Infant Interactions (Noldus, Netherlands)
  • Parent stimulatory contact - the Coding of Parent Infant Interactions (Noldus, Netherlands)

Design—Correlational

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Findings

  1. Mothers and fathers show similar baseline levels of plasma and salivary oxytocin (OT).
  2. Plasma and salivary OT are inter-related.
  3. OT is individually stable across observations.
  4. Maternal and paternal OT is differentially related to affectionate and stimulatory contact.
  5. OT increases in high-affectionate contact mothers following mother-infant contact but not in low-affectionate contact mothers.
  6. OT increases in high-stimulatory contact fathers following parent-infant contact but not in low-stimulatory contact fathers.

Limitations

  • The results do not imply causal relations, and the links may be accounted for by other variables.
  • The medium-size correlation between plasma and salivary OT may point to a shared mechanism underlying the functioning of these two peripheral systems.
  • Several studies have not found an OT increase following touch; thus, the conditions under which touch does or does not increase OT need further study.