ARS | Publication request: Osteopenic effects of MgSO4 in multiple pregnancies.

Submitted to: Journal of Pediatric Endocrinology & Metabolism
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2006
Publication Date: October 16, 2006
Citation: Kaplan, W., Haymond, M., McKay, S., Karaviti, L.P. 2006. Osteopenic effects of MgSO4 in multiple pregnancies. Journal of Pediatric Endocrinology & Metabolism. 19(10):1225-1230.

Interpretive Summary: In women with preterm labor, Magnesium Sulfate (MgSO4) infusions are used to inhibit labor and prevent the delivery of very premature infant. Therapy with MgSO4 is known to impact adversely calcium metabolism in the mother and fetus. Most of the cases reported in the literature document focal and mild forms of thinning of the newborn bones (neonatal osteopenia). We are reporting information from four sets of multiple pregnancies in which the infants were found to have severe neonatal osteopenia (very thin bones) and X-ray findings of fractures. These effects appeared to be positively associated with the total dose of MgSO4 used in these women, and inversely with the infants’ gestational ages. With the use of in vitro fertilization and other methods to induce pregnancy, the frequency of multiple pregnancies (twins, triplets, etc) has dramatically increased. Thus MgSO4 is being used far more frequently and for longer periods of time in these women who frequently experience preterm labor. Thus this report helps to increase the awareness of the clinicians caring for these women and that of the neonatologist and general pediatricians of the risks of the use of large amounts of MgSO4 in these infants, so they might avoid fractures from minor trauma in these children over the days and weeks following delivery.

Technical Abstract: To describe the effects of prolonged maternal treatment with MgSO4 in infants who were products of multiple pregnancies. Case series of infants presenting with osteopenia secondary to MgSO4 administration for preterm labor. Ten premature infants with hypermagnesemia (4.5+/-0.2 mg/dl), hypocalcemia (6.0 +/-0.3 mg/dl), and high serum alkaline phosphatase (574+/-96 U/l) underwent imaging studies that showed diffuse osteopenia of the long bones and probable rib fractures. All mothers had isolated premature labor, for which they were given MgSO4; (average dose 3.66+/-0.08 kg/ pregnancy over 10.0+/-0.5 weeks). On follow-up (to 9 months), all infants had complete or near complete resolution of the osteopenia. Premature infants who are exposed to large doses of MgSO4, especially those of multiple pregnancies, have an increased risk of developing hypocalcemia, osteopenia, and fractures. Our findings indicate that these infants should be identified at birth and managed prospectively.