title: Magnesium sulfate as a second-line tocolytic agent for preterm labor: a randomized controlled trial in Kyushu Island.
abstract: OBJECTIVE
  We evaluated the efficacy of magnesium sulfate as a second-line tocolysis for 48  hours.
  
  
  METHODS
  A multi-institutional, simple 2-arm randomized controlled trial was performed. Forty-five women at 22 to 34 weeks of gestation were eligible, whose ritodrine did not sufficiently inhibit uterine contractions. After excluding 12 women, 33 were randomly assigned to either magnesium alone or combination (ritodrine and magnesium). The treatment was determined as effective if the frequency of uterine contraction was reduced by 30% at 48  hours of the treatment.
  
  
  RESULTS
  After magnesium sulfate infusion, 90% prolonged their pregnancy for >48 hours. Combination therapy was effective in 95% (18/19), which was significantly higher than 50% (7/14) for magnesium alone.
  
  
  CONCLUSIONS
  This randomized trial revealed that combination therapy significantly reduced uterine contractions, suggesting that adjuvant magnesium with ritodrine is recommended, rather than changing into magnesium alone, when uterine contractions are intractable with ritodrine infusion.
authors.affiliation: Department of Obstetrics and Gynecology, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kawagoe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sameshima
authors.forename: Tsuyomu
authors.initials: T
authors.lastname: Ikenoue
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yasuhi
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Kawarabayashi
mesh_terms: D000328:Adult; D004359:Drug Therapy, Combination; D005260:Female; D005865:Gestational Age; D006801:Humans; D057194:Intention to Treat Analysis; D007564:Japan; D008278:Magnesium Sulfate / Q000494:pharmacology / Q000627:therapeutic use*; D007752:Obstetric Labor, Premature / Q000188:drug therapy*; D011247:Pregnancy; D012312:Ritodrine / Q000494:pharmacology / Q000627:therapeutic use*; D018709:Statistics, Nonparametric; D015149:Tocolytic Agents / Q000627:therapeutic use*; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D015149:Tocolytic Agents; D008278:Magnesium Sulfate; D012312:Ritodrine