Spells, tremors, irritability: Warning signs of B12 deficiency in babies

Spells, tremors, and irritability are common and early findings in infants with vitamin B12 deficiency, a recent Norway study has found. Prenatal exposure to nitrous oxide, typically given during labour, may be a risk factor.

Researchers conducted a case-control study of 85 infants born between 2011 and 2018 and who had been diagnosed with vitamin B12 deficiency. Parent-completed questionnaires were used for the assessment of presentations and potential risk factors. A parallel group of 252 healthy infants was also included as a control.

Eighty percent of vitamin B12-deficient infants showed symptoms within the first 2 months of life, the most common of which were head lags at pull-to-sit test (49 percent); spells; including motor seizures, apnoeas, or absences (39 percent); tremors (29 percent); irritability (18 percent); and abnormal eye contact (13 percent).

Logistic regression analysis revealed that maternal B12 deficiency (odds ratio [OR], 2.23, 95 percent confidence interval [CI], 1.00-4.97; p=0.05) and exclusive breastfeeding (OR, 2.58, 95 percent CI, 1.35–4.92; p=0.004) were significant risk factors for infant vitamin B12 deficiency.

Similarly, among B12-deficient babies, nitrous oxide dose during labour correlated with the log-transformed concentration of total homocysteine (β, 0.002, 95 percent CI, 0.001–0.003; p=0.002), an indicator of vitamin B12 levels.

“Maternal use of nitrous oxide in labour should be considered a novel risk factor to be included in a prospective study. Unnecessary referrals and hospital admissions could be reduced with increased education in paediatric healthcare to include B12 status in breastfed infants with subtle and overt neurological symptoms and signs,” the researchers said.