Serum magnesium levels of term neonates with birth asphyxia and relationship to severity of asphyxia.

BACKGROUND AND AIMS: Birth asphyxia is one of the three main causes of neonatal mortality in Nigeria. Hypomagnesaemia has been reported amongst severely asphyxiated babies. Despite this, the prevalence of hypomagnesaemia amongst newborns with birth asphyxia has not been well researched in Nigeria. This study set out to determine the prevalence of hypomagnesaemia in term neonates with birth asphyxia and the relationship (if any) between magnesium levels and the severity of birth asphyxia or encephalopathy.

METHODS

In this cross-sectional analytical study, the serum magnesium levels of consecutive cases of birth asphyxia were compared to that of gestational age-matched healthy term neonates. Babies with Apgar scores <7 in the 5th minute of life were recruited into the study. Blood samples were taken from each baby at birth and 48 h. Serum magnesium was measured using spectrophotometry.

RESULTS

Hypomagnesaemia was found in 36 (35.3%) babies with birth asphyxia and 14 (13.7%) healthy controls; this difference was statistically significant (χ2 = 18.098, P = 0.001), with an odds ratio of 3.4 (95% confidence interval = 1.7, 6.9). The median (interquartile range) levels of serum magnesium in babies with mild, moderate and severe asphyxia were 0.7 mmol/L (0.5-1.1), 0.7 mmol/L (0.4-0.9) and 0.7 mmol/L (0.5-1.0), respectively (P = 0.316), while those of babies with mild (stage 1), moderate (stage 2) and severe (stage 3) encephalopathy were 1.2 mmol/L (1.0-1.3), 0.7 mmol/L (0.5-0.8) and 0.8 mmol/L (0.6-1.0), respectively (P = 0.789).

CONCLUSION

This study has shown that hypomagnesaemia was more common in babies with birth asphyxia and there was no relationship between magnesium levels and the severity of asphyxia or encephalopathy.