Abstract
Background and Objectives: Infantile colic affects 15-40% of infants ≤ 5 months, burdening families and health systems. While the effects of intrapartum oxytocin on neonatal outcomes have been widely investigated, its potential link with infantile colic remains poorly understood. We evaluated whether synthetic oxytocin is associated with infantile colic during the first five months of life and explored neonatal head circumference, feeding type and epidural anesthesia as additional factors. Materials and Methods: Prospective 1:1 matched case-control study in three Spanish pediatric outpatient clinics. Parents of 76 term infants aged 0-5 months (38 cases, 38 controls) completed face-to-face structured interviews documenting synthetic oxytocin and epidural use, infant anthropometry and feeding pattern. Infantile colic was diagnosed by Rome IV criteria. Associations were estimated with conditional logistic regression, producing adjusted odds ratios and 95% confidence intervals. Results: Synthetic oxytocin was used in 57.9% of deliveries and epidural anesthesia in 81.6%. Synthetic oxytocin showed no association with infantile colic (aOR 1.24; 95% CI 0.50-3.09). Epidural strongly predicted synthetic oxytocin exposure (aOR 4.55; 95% CI 1.28-16.20) but had no independent link to infantile colic. Infants with colic had a smaller mean head circumference at birth, although this difference did not remain significant after adjusting for gestational age, likely reflecting limited sample size. Synthetic oxytocin was not associated with breastfeeding status. Conclusions: In this cohort, intrapartum synthetic oxytocin was not related to infantile colic or to feeding difficulties. Smaller head circumference among colic cases may warrant further investigation as a potential risk marker. The high co-use of synthetic oxytocin and epidural underscores the need for larger longitudinal studies to clarify their peripartum-neonatal interactions.