title: Effect of magnesium on fetal heart rate variability using computer analysis.
abstract: We studied 16 women, at 32 weeks' or more gestation who required magnesium sulfate (MgSO4) therapy for preterm labor or preeclampsia. A 60-minute Doppler fetal heart rate (FHR) tracing, analyzed by the Oxford Sonicaid System 8000, was obtained for 1 hour before and 2 hours after each patient received intravenous MgSO4 therapy. Maternal serum Mg2+ levels were obtained at the second monitoring session. Matched paired measures of FHR parameters were compared with the Student's t test. After MgSO4 administration, we noted significant falls in long-term variability, short-term variability, and total acceleration (more than 10 beats/min) counts. Reduced short-term and overall variability occurred in all cases with maternal serum Mg2+ levels more than 4.6 mg/dL. Therapeutic maternal serum Mg2+ levels are linked with decreases in long-term and short-term FHR variability and acceleration counts. These findings should be considered when evaluating resting FHR baseline of patients thus treated.
authors.affiliation: Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Hiett
authors.forename: L D
authors.initials: LD
authors.lastname: Devoe
authors.forename: H L
authors.initials: HL
authors.lastname: Brown
authors.forename: J
authors.initials: J
authors.lastname: Watson
mesh_terms: D000328:Adult; D001330:Electronic Data Processing; D005260:Female; D005323:Fetal Monitoring; D006340:Heart Rate, Fetal / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D008274:Magnesium / Q000097:blood / Q000494:pharmacology*; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000494:pharmacology; D007752:Obstetric Labor, Premature / Q000188:drug therapy; D011225:Pre-Eclampsia / Q000188:drug therapy; D011247:Pregnancy; D016216:Ultrasonography, Prenatal
chemical_list: D008278:Magnesium Sulfate; D008274:Magnesium