Troy Brown RN
August 07, 2018
Children whose mothers consumed alcohol during lactation are more likely to experience "dose-dependent reductions in abstract reasoning at age 6 to 7 years," but the effect wanes by age 8 to 11 years, a study has found. The attenuation of the effect in older youth may result from additional years of education.
In addition, traditional methods used by women to reduce the amount of alcohol in their breast milk after drinking appear to be ineffective or unpredictable at best.
"Alcohol passes quickly through to breastmilk at similar concentrations to maternal blood alcohol concentration and reduces milk production. Although drinking alcohol immediately after feeding minimizes ethanol exposure, not all women use this technique, and unpredictable infant feeding can mar such attempts," the researchers write.
Pumping and dumping, a common practice in which women pump and discard breast milk for a short time after alcohol consumption, does not decrease ethanol concentration in breast milk, as the concentration in the breast milk will remain elevated as long as there is alcohol present in the mother's blood, the authors explain.
Louisa Gibson, Grad Dip Psych, BSc(Psych) Hons, and Melanie Porter, MAPS, BPsych, MClinNeuropsych, PhD, both from the Department of Psychology, Faculty of Human Sciences, Macquarie University, Sydney, Australia, published their findings online July 30 in Pediatrics.
The researchers analyzed data from Growing Up in Australia: The Longitudinal Study of Australian Children. The study includes 5107 infants who are assessed every 2 years. The investigators used multivariable linear regression analyses to study the associations between alcohol consumption and smoking by breast-feeding mothers and offspring's scores on three measures (Matrix Reasoning, Peabody Picture Vocabulary Test–Third Edition, and Who Am I?) over time.
Breast-fed infants whose mothers consumed alcohol were more likely to have reduced Matrix Reasoning scores at age 6 to 7 years (B coefficient [B], -0.11; 95% confidence interval [CI], -0.18 to -0.04; P = .01).
This association was absent in those who had never breast-fed (B, -0.02; 95% CI, -0.20 to 0.17; P = .87).
This finding suggests "alcohol exposure through breast milk was responsible for the findings. What is more difficult to ascertain and quantify, however, are the potential effects of other environmental and genetic risks that can lead to results such as those reported in this study," Lauren M. Jansson, MD, from the Department of Pediatrics, School of Medicine, Johns Hopkins University, Baltimore, Maryland, writes in a related commentary.
"The finding is not surprising when we consider the potential pharmacokinetic basis for it and the known harmful effects of alcohol on the developing brain," continues Jansson. "Alcohol concentrations in breast milk resemble those in maternal blood within 30 to 60 minutes of ingestion; the amount of alcohol in breast milk is ∼5% to 6% of the weight-adjusted maternal dose, and newborns metabolize alcohol at approximately half the rate of adults."
Smoking during breast-feeding was not linked to any outcome variable.
Study limitations include the fact that the study failed to record neither the frequency and quantity of milk the infants consumed nor the timing of alcohol consumption or the quantity of ethanol in breast milk.
"Although findings in this study were independent of prenatal alcohol consumption, pregnancy alcohol use was recorded by maternal self-report retrospectively, and there are often multiple psychosocial and other pressures for women to deny gestational substance use," Jansson writes.
Moreover, women who drink alcohol during pregnancy or lactation may have other maladaptive behaviors that interfere with their parenting ability, she adds.
The authors and editorialist have disclosed no relevant financial relationships.