Abstract
Pre-eclamptic mothers (n=22) treated with MgSO4, and their infants (32-44 wks gestation) were studied during labor and the first 3 days of postnatal life. Maternal serum Mg increased from 2.09±.09mg/dl (mean±SEM) prestudy to peak 5.54±.52 and 4.44±.41 at delivery. Neonatal Mg at 6-12 hrs of age (4.15±.20) was lower than placental vein Mg (4.79±.38), paired t, p<.05, and continued to fall postnatally (3.39±.15 at 24 hrs, 3.07±.15 at 48 hrs), but remained elevated (3.03±.18) at 72 hrs. Infant serum Mg at 48 and 72 hrs of age was higher in premature infants (Mg vs gestation, r=-.679, p<.01 and r=-.628, p<.05). Infants with birth asphyxia (1-min Apgar ≤6) had higher serum Mg at 48 hrs (3.60±.42 vs 2.86±.10, p<.05). Urinary Mg excretion was low, .094±.048 mg/day on day 1, but increased to 5.47±4.91 on day 3 (n=5, paired t, p<.07). Infant serum Mg at 24, 48 and 72 hrs was directly related to maternal Mg levels prestudy (r=.679 - .792, p<.05) and at 24 and 48 hrs was directly related to the total dose of Mg given to the mother (r=.737, .704, p<.01). Four infants judged to be hypotonic by an observer blind to Mg levels (arbitrary neurologic scale) had higher Mg levels at 24 and 72 hrs (p<.05). No relation of serum Mg with electrocardiograms was shown; PR was prolonged (>.12 sec) in 5 of 10 infants and prolonged QTc (>.4 sec) in 4 of 10. Thus, maternal Mg excess is associated with prolonged neonatal hypermagnesemia; premature and birth asphyxiated infants have greater intolerance to Mg excess.
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Donovan, E., Steichen, J., Strub, R. et al. PERINATAL HYPERMAGNESEMIA: RELATION TO GESTATIONAL AGE AND BIRTH ASPHYXIA. Pediatr Res 11, 416 (1977). https://doi.org/10.1203/00006450-197704000-00280
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DOI: https://doi.org/10.1203/00006450-197704000-00280