How to manage emergencies associated with tocolysis for preterm labor
Although short-term tocolysis usually is safe, certain agents and scenarios may increase the risk of harm. Here, four cases involving serious complications.
Beta-adrenergic agonists carry many risks
Fetal effects of magnesium sulfate
In May 2013, the FDA issued a warning about the risk of neonatal complications with long-term maternal magnesium administration. These complications include osteopenia, low calcium, and bone fracture. The pregnancy category for magnesium sulfate will be changed from “A” to “D” because of these teratogenic effects.12
CASE 4 Resolved
Because magnesium is mainly cleared by renal excretion, the clinician administers the medication with caution in this patient with reduced renal function. The clinician administers the same 4- to 6-g bolus that would be given a patient with normal kidney function, but the maintenance dose is reduced to 1 g. Magnesium levels are obtained every 12 hours or when clinically indicated.
Bottom line: Be ready to act
The short-term use of tocolytic therapy usually is not associated with maternal or fetal complications. After initial administration, maintenance tocolytic therapy probably does not prolong gestation.
Given the potential for harm without additional fetal benefit associated with extended therapy, I recommend that clinicians follow current clinical guidelines from ACOG for use of tocolytic agents. In the process, be vigilant for complications and be ready to act appropriately. Keep maternal and fetal conditions in mind when selecting a tocolytic agent.
