A previous study by our group has shown a potential link between the use of nitrous oxide for pain relief during labour and the subsequent diagnosis of developmental delay in the children. The current study extends these findings through the urinary metabolic analysis on 13 children who have been diagnosed with autism (developmental delay), and who were born to 11 mothers who used nitrous oxide for pain relief during labour. Elevated levels of the methylB12 deficiency markers, HVA, VMA, QA and pyroglutamic acid, were found supporting the notion that there had been extensive inactivation of the enzyme methionine synthase. There was lack of correlation between either MMA – a marker of Adenosyl B12 deficiency, and glutaric acid, a marker of functional B2 deficiency. The results are consistent with the known ability of nitrous oxide to form NO-Co(III)cobalamin, which subsequently irreversibly inactivates the enzyme methionine synthase. The data is in direct opposition to the contention of many anaesthetists, obstetricians and maternity staff who claim that nitrous oxide is harmless to the mother and baby. The findings are consistent with the hypothesis that the increased usage of nitrous oxide during labour has been a major factor in the 30-fold increase in the rate of autism in the past 30 years. The findings strongly suggest that nitrous oxide should be banned during labor.

Lay Summary: The current study supports the contention that the use of nitrous oxide for pain relief during labour has been a major factor in inactivating Methyl B12 through the formation of NO-Co (III)B12, and the presence of the inactive vitamin B12 in the brains of the children has led to the developmental delay.