Preterm Labor

Preterm labor • Between 20-37 wks • ↑ fetal M&M • Pt may given tocolytic therapy if there is no C/I • β -agonist: Ritodrine and terbutaline o For short term only to allow time for lung maturity after steroids o The effect persist to 60-90 min after D/C, need at least 10 min D/C before giving anesthetic o S/E: hyperglycemia, tachycardia, with possible arrhythmia, pul edema, myocardial ischemia, hypotension, cerebral vasospasm, fetal tachycardia, rebound hypoglycemia o Avoid overzealous hydration which may ↑ risk of pul edema, and hyperventilation → ↓K o Lidocaine IV may prevent arrhythmia • MgSO4 o See PIH for S/E, less severe than β -agonist o Risk of hypotension with spinal/epidural o ↑ sensitivity to NDMR

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PG synthesis inhibitor o Mainly NSAID o Not to be given after 37 wks → close ductus arteriosis o Possible ↑ risk of epidural hematoma o ↑ risk of ante and postpartum bleeding CCB o Cause hypotension o ↑ risk of hypotension with neuraxial blockade NTG o Short acting