PSYCHOSOCIAL FACTORS ASSOCIATED WITH MATERNAL PLASMA OXYTOCIN IN LATE PREGNANCY: A MULTIVARIABLE ANALYSIS.

CONTEXT: Oxytocin (OXT) supports social affiliation and affect regulation; in late pregnancy, variability in plasma OXT may index the psychosocial context relevant to perinatal risk.

OBJECTIVES

To test (i) differences in plasma OXT by adult attachment (AAS/R-AAS); (ii) associations with pregnancy planning, partner support, maternal perception, and history of emotional difficulties; and (iii) psychosocial factors independently associated with OXT.

DESIGN

Cross-sectional study.

SUBJECTS AND

METHODS

Thirty-five women at 28-39 weeks' gestation (subsample of 140) provided morning EDTA plasma (08:00-10:00), stored at -80 °C. OXT was quantified by ELISA without solid-phase extraction or technical duplicates. Analyses comprised one-way ANOVA with Bonferroni tests, non-parametric contrasts (Mann-Whitney/Kruskal-Wallis with Holm adjustment), and HC3-robust multiple regression (α=0.05).

RESULTS

OXT differed by attachment (secure > avoidant > anxious-ambivalent; F(2,32)=31.115, p<0.001, ηp2=0.660). Univariate contrasts indicated higher OXT with planned pregnancy, partner support, positive (vs negative) maternal perception, and with a history of emotional difficulties; in the multivariable model (R2=0.718; adjusted R2=0.617), only attachment independently predicted OXT (avoidant vs secure B=-227.7 pg/mL; anxious-ambivalent vs secure B=-289.4 pg/mL).

CONCLUSIONS

In late pregnancy, plasma OXT co-varies with adult attachment and, at group level, with proximal psychosocial factors; after adjustment, attachment remains the dominant predictor. Psychosocial screening is clinically actionable, whereas OXT measurement should remain a research tool.