Green beer and Irish Car Bombs are all around you, but can you safely partake if you're breastfeeding? Short answer: yes, in moderation.
Let's explore the data. A systematic search of 41 publications on lactation and alcohol demonstrated that alcohol concentrations in breast milk closely resemble those in maternal blood. That means that if a typical mom drinks three glasses of 12% ABV wine in 2 hours and then feeds baby, her breastmilk would contain 0.1% ABV. Thus, they conclude, "even in a theoretical case of binge drinking, the children would not be subjected to clinically relevant amounts of alcohol" (Haastrup et al., 2014). Further, a study performed in Australia showed that low level drinking during breastfeeding is not linked with adverse feeding, sleeping, or developmental outcomes in infants up to 12 months of age (Wilson et al., 2017). For this study, low level drinking means ≤14 standard drinks per week, <3 per occasion.
It's best to partake in moderation, however, as maternal alcohol consumption is associated with child behavioral problems (Lund et al., 2020) and "appears to be a risk factor for sudden infant death syndrome [SIDS]" (Phillips et al., 2011). It is unclear, however, whether alcohol is causal for SIDS (direct cause), or merely correlated (an indirect relationship).
So feel free to grab that green beer, but it's still best to enjoy in moderation!
Source:
Wilson J, Tay RY, McCormack C, Allsop S, Najman J, Burns L, Olsson CA, Elliott E, Jacobs S, Mattick RP, Hutchinson D. Alcohol consumption by breastfeeding mothers: Frequency, correlates and infant outcomes. Drug Alcohol Rev. 2017 Sep;36(5):667-676.
Haastrup MB, Pottegård A, Damkier P. Alcohol and breastfeeding. Basic Clin Pharmacol Toxicol. 2014 Feb;114(2):168-73.
Lund IO, Moen Eilertsen E, Gjerde LC, Ask Torvik F, Røysamb E, Reichborn-Kjennerud T, Ystrom E. Maternal Drinking and Child Emotional and Behavior Problems. Pediatrics. 2020 Mar;145(3):e20192007.
Phillips DP, Brewer KM, Wadensweiler P. Alcohol as a risk factor for sudden infant death syndrome (SIDS). Addiction. 2011 Mar;106(3):516-25.