Safety of Prolonged Lactobacillus reuteri Use in Your 5-Month-Old Infant
No, giving BioGaia (Lactobacillus reuteri) probiotics to your 5-month-old son for 3 months and 20 days has not caused harm. Current evidence indicates that adverse events from long-term probiotic supplementation in healthy infants are uncommon, and L. reuteri DSM 17938 has demonstrated a favorable safety profile in clinical trials 1.
Safety Evidence for Extended Use
The available evidence strongly supports the safety of prolonged L. reuteri administration in healthy term infants:
A 2023 guideline review examining probiotic use in infants concluded that reports of adverse events occurring with long-term probiotic supplementation are uncommon 1.
A randomized controlled trial specifically evaluating L. reuteri DSM 17938 in infants with colic found no severe adverse events during 42 days of daily administration, with follow-up extending to 134 days 2.
Another trial administering L. reuteri NCIMB 30351 for 25 consecutive days reported no adverse events in the study population 3.
Duration Context
Your son received probiotics for approximately 110 days (3 months and 20 days), which falls within the timeframe studied in clinical trials:
The longest controlled trial followed infants receiving L. reuteri for 42 days with extended observation to 134 days without safety concerns 2.
Studies examining colic prevention have used L. reuteri for 4 weeks prenatally plus several months postnatally without reported harm 4.
Important Safety Distinctions
Your son's situation differs significantly from high-risk populations where caution is warranted:
Safety concerns with probiotics primarily apply to preterm infants (<37 weeks gestational age), immunocompromised infants, critically ill patients with central venous catheters, infants with cardiac valvular disease, or short-gut syndrome 5, 6.
At 5 months old and presumably healthy (since prescribed for colic, a functional disorder), your son does not fall into these high-risk categories 5, 6.
Product Quality Consideration
The main safety concern with probiotics relates to manufacturing contamination rather than the probiotic organism itself:
Fatal infections in preterm infants have occurred due to contaminated probiotic products, not from the probiotic strains themselves 5, 6.
BioGaia is a pharmaceutical-grade product with established quality control, which minimizes this risk 5.
Clinical Context
The evidence on L. reuteri efficacy for colic is mixed, but safety remains consistent:
Some trials show significant reduction in crying time (44-144 minutes daily) 3, 7, while others show no benefit or even increased fussing 8.
Regardless of efficacy, safety profiles across all trials remain favorable with no serious adverse events attributed to the probiotic 3, 2, 8.
Common Physiological Finding
One trial noted that 55% of infants with colic presented with low absolute neutrophil counts (<1500/mm³), which resolved spontaneously in all subjects by day 176, occurring equally in both probiotic and placebo groups 2. This represents a benign finding associated with infantile colic itself, not probiotic administration 2.
Moving Forward
You can discontinue the probiotic without concern, as your son has passed the typical colic age (which usually resolves by 3-4 months):