Effects of Maternal Magnesium Sulfate Administration on Intestinal Blood Flow Velocity in Preterm Neonates

Abstract

Background: Antenatal MgSO₄ administration is used extensively as a tocolytic agent and to treat preeclampsia. Various effects on the fetus and newborn have been reported, and MgSO₄ has well-documented vasoactive effects. Objective: To determine if antenatal MgSO₄ administration affects intestinal blood flow velocity in newborn preterm infants. Methods: Peak, mean and end-diastolic velocities in the superior mesenteric artery were measured on day 1 of life. Maternal medical records were reviewed to identify infants whose mothers had been administered MgSO₄ for preterm labor or preeclampsia within 24 h of delivery. Result: Fifty-six infants were studied: 27 were exposed and 29 were not exposed to antenatal MgSO₄. Mean birth weight (1,371 ± 349 and 1,401 ± 469 g, respectively), gestational age (29.7 ± 2.0 and 30.0 ± 2.9 weeks, respectively) and infant hemodynamic and clinical variables (other than clinical indication for antenatal MgSO₄ administration) were similar between groups. There were no significant differences between the exposed and unexposed groups in intestinal blood flow velocities. For the exposed group, however, there was a significant negative correlation between mean velocity and the number of hours from birth to the time superior mesenteric artery blood flow velocity measurements were made (p = 0.002); there was no correlation for the unexposed group (p = 0.852). Conclusion: Group mean values indicate that antenatal exposure to MgSO₄ does not significantly affect intestinal blood flow velocity in newborn preterm infants. However, the significant negative relationship between mean blood flow velocity and time from birth to blood flow velocity measurement in exposed infants suggests that there may be measurable effects of MgSO₄ exposure within the hours immediately after birth. Trials that prospectively evaluate the development of intestinal blood flow velocities are needed to further clarify potential effects of antenatal MgSO₄ on the gastrointestinal tract of preterm infants.

Magnesium sulphate and cardiovascular and cerebrovascular adaptations to asphyxia in preterm fetal sheep

“…One study suggested antenatal MgSO 4 treatment was associated with increased intestinal blood flow immediately after preterm birth (Havranek et al . ). The present finding that MgSO 4 increases peripheral perfusion indicates that it would be valuable to carefully assess whether the risk of NEC and renal impairment are affected by MgSO 4 exposure.…”

Lack of Evidence for Time or Dose Relationship between Antenatal Magnesium Sulfate and Intestinal Injury in Extremely Preterm Neonates

“…MgSO 4 decreases intestinal peristalsis [13], can possibly alter mesenteric blood flow [14, 15], and is associated with feeding intolerance in neonates [16]. It also crosses the placenta freely with a linear relationship between maternal and neonatal levels [17-19].…”

Short‐term morbidities and neurodevelopmental outcomes in preterm infants exposed to magnesium sulphate treatment

“…Exposed preterm infants may be at risk for hypermagnesemia and its associated complications as well. Several studies implicate increased neonatal morbidities in the presence of high mMgC or iMgC, among them increased risk of death, high grade IVH, risk for intubation and patent ductus arteriosus . In view of the preceding risks, the American Academy of Pediatrics and the Neonatal Resuscitation Program supported by the American Heart Association listed MgSO4 among the maternally administered medications that may cause respiratory depression in newborns .…”