Study of association of maternal vitamin D deficiency with hypocalcaemic seizures in exclusively breast-fed infants

Background: Hypocalcaemia is a common metabolic cause of seizures in early infancy. Improper formula feeds and lack of breast feeding have been established causes of hypocalcaemia and subsequent rickets in infants. There is a close correlation between the Vitamin D status of mothers and their infants. There is limited information regarding the vitamin D status of lactating mothers and their hypocalcaemic infants.

Objectives: To determine the association between maternal vitamin D levels and hypocalcaemic seizures in exclusively breast-fed infants.

Method: We conducted an analytical cross-sectional study from January 2018 to June 2019 in Cheluvamba Hospital, Mysore Medical College and Research Institute, Mysuru, India in a cohort of 40 mother-infant dyads who were exclusively breast-fed and had hypocalcaemic seizures. Serum calcium, phosphorus and alkaline phosphatase of the infants and serum 25 hydroxyvitamin D [25 (OH) D] levels of both mothers and infants were measured and the results were analysed.

Results: Mean ages of the studied infants and mothers were 12.95 ± 8.13 weeks and 22.15 ± 2.46 years respectively. All infants had normal anthropometry whereas 70% of the mothers were underweight. Of the 40 infant-mother pairs studied, 34 (85%) infants and 33 (82.5%) mothers had subnormal 25 (OH) D levels. Mean serum calcium, phosphorus and alkaline phosphatase levels in the infant were 6.46 ± 1.05 mg/dl, 3.63 ± 1.03 mg/dl and 785.87 ± 235.49 IU/L respectively. Mean 25 (OH) D levels in the infants and mothers were 20.85 ± 5.80 ng/ml and 21.95 ± 4.45 ng/ml respectively. We found significant correlation between the serum calcium levels and the 25 (OH) levels of the infants and mothers (p<0.001); similar correlation was found between the infant and maternal 25 (OH) D level (p<0.001).

Conclusions: Most exclusively breast-fed infants with hypocalcaemic seizures had subnormal 25 (OH) D levels and they strongly correlated with the maternal 25 (OH) D levels.  

Sri Lanka Journal of Child Health, 2022; 51(1): 106-110