Magnesium sulfate exposure and neonatal intensive care unit admission at term.

OBJECTIVE: The aim of this study was to investigate the effect of maternal magnesium sulfate (MgSO4) exposure for eclampsia prophylaxis on neonatal intensive care unit (NICU) admission rates for term newborns. STUDY DESIGN: A secondary analysis of the Maternal-Fetal Medicine Unit Network Cesarean Registry, including primary and repeat cesarean deliveries, and failed and successful trials of labor after cesarean was conducted. Singleton pregnancies among women with preeclampsia and >37 weeks of gestation were included. Pregnancies with uterine rupture, chorioamnionitis and congenital malformations were excluded. Logistic regression analysis was used to determine associations between MgSO4 exposure and NICU admission. P<0.05 was considered statistically significant. RESULT: Two thousand one hundred and sixty-six term pregnancies of women with preeclampsia were included, of whom 1747 (81%) received MgSO4 for eclampsia prophylaxis and 419 (19%) did not. NICU admission rates were higher among newborns exposed to MgSO4 vs unexposed (22% vs 12%, P<0.001). After controlling for neonatal birth weight, gestational age and maternal demographic and obstetric factors, NICU admission remained significantly associated with antenatal MgSO4 exposure (adjusted odds ratio 1.9, 95% confidence interval 1.3 to 2.6, P<0.001). Newborns exposed to MgSO4 were more likely to have Apgar scores <7 at 1 and 5 min (15% vs 11% unexposed, P=0.01 and 3% vs 0.7% unexposed, P=0.008). There were no significant differences in NICU length of stay (median 5 (range 2 to 91) vs 6 (3 to 15), P=0.5). CONCLUSION: Antenatal maternal MgSO4 treatment was associated with increased NICU admission rates among exposed term newborns of mothers with preeclampsia. This study highlights the need for studies of maternal MgSO4 administration protocols that optimize maternal and fetal benefits and minimize risks.

Effect of magnesium sulfate exposure on term neonates.

OBJECTIVE: To compare neonatal intensive care unit and special care unit (NICU) admission rates between term neonates exposed to antenatal magnesium sulfate (MS) and those unexposed. STUDY DESIGN: We performed a retrospective cohort study of all singleton neonates ≥37 weeks born to women with pre-eclampsia from August 2006 to July 2008. Cases were defined by antenatal exposure to MS and controls by absence of MS exposure. The primary outcome was NICU admission. Data were analyzed via univariable and multivariable regression analyses. RESULT: In all, 28 (14.7%) out of 190 MS-exposed neonates ≥37 weeks were admitted to the NICU, compared with 4 (5.4%) of 74 non-exposed neonates (P=0.04). This association persisted after controlling for potential confounding variables including severe pre-eclampsia and cesarean delivery (AOR 3.69, 1.13 to 11.99). NICU admission was associated in a dose-dependent relationship with total hours and mean dose of MS exposure. Number needed to harm with MS was 11 per NICU admission. Among neonates admitted to the NICU, MS-exposed were more likely to require fluid and nutritional support than unexposed neonates (60.7 vs 0%, P=0.04), and trended toward more frequent requirement for respiratory support and greater length of stay. CONCLUSION: In term neonates, MS exposure may be associated independently with NICU admission in a dose-dependent relationship. Requirements for fluid and nutritional support are common in this group, likely due to feeding difficulties in exposed neonates. Assessment of acute care needs among all neonates exposed to MS for maternal eclampsia prophylaxis should be considered.