Influence of Probiotics on Early Gut Microbial Colonization

The goal of this clinical trial is to learn whether daily probiotic drops plus vitamin D3 can improve early gut microbiome colonization in healthy infants born by C-section. It will also assess safety and tolerability.

An intervention with probiotics + vitamin D3 will be compared to placebo + vitamin D3 in a double-blind, randomized design, and include an open-label vaginal-born reference group.

Participants will receive study drops daily for 8 weeks and provide stool samples at multiple time points and complete questionnaires/diaries. After the intervention period, there is an optional follow-up period for up to 3 years.