title: Effect of tocolytic drugs on fetal heart rate variability: a systematic review.
abstract: BACKGROUND
  Tocolytics may cause changes in fetal heart rate (HR) pattern, while fetal heart rate variability (HRV) is an important marker of fetal well-being. We aim to systematically review the literature on how tocolytic drugs affect fetal HRV.
  
  
  METHODS
  We searched CENTRAL, PubMed and EMBASE up to June 2016. Studies published in English, using computerized or visual analysis to describe the effect of tocolytics on HRV in human fetuses were included. Studies describing tocolytics during labor, external cephalic version, pre-eclampsia and infection were excluded. Eventually, we included six studies, describing 169 pregnant women.
  
  
  RESULTS
  Nifedipine, atosiban and indomethacin administration show no clinically important effect on fetal HRV. Following administration of magnesium sulfate decreased variability and cases of bradycardia are described. Fenoterol administration results in a slight increase in fetal HR with no changes in variability. After ritodrine administration increased fetal HR and decreased variability is seen. The effect of co-administration of corticosteroids should be taken into account.
  
  
  CONCLUSIONS
  In order to prevent iatrogenic preterm labor, the effects of tocolytic drugs on fetal HRV should be taken into account when monitoring these fetuses.
authors.affiliation: a Department of Obstetrics and Gynecology , Máxima Medical Center , Veldhoven , the Netherlands and.
authors.forename: Kim M J
authors.initials: KMJ
authors.lastname: Verdurmen
authors.affiliation: a Department of Obstetrics and Gynecology , Máxima Medical Center , Veldhoven , the Netherlands and.
authors.forename: Alexandra D J
authors.initials: ADJ
authors.lastname: Hulsenboom
authors.affiliation: a Department of Obstetrics and Gynecology , Máxima Medical Center , Veldhoven , the Netherlands and.
authors.forename: Judith O E H
authors.initials: JOEH
authors.lastname: van Laar
authors.affiliation: a Department of Obstetrics and Gynecology , Máxima Medical Center , Veldhoven , the Netherlands and.|b Faculty of Electrical Engineering , Eindhoven University of Technology , Eindhoven , the Netherlands.
authors.forename: S Guid
authors.initials: SG
authors.lastname: Oei
mesh_terms: D002121:Calcium Channel Blockers / Q000009:adverse effects*; D005260:Female; D006340:Heart Rate, Fetal / Q000187:drug effects*; D006801:Humans; D008278:Magnesium Sulfate / Q000009:adverse effects*; D011247:Pregnancy; D015149:Tocolytic Agents / Q000009:adverse effects*
chemical_list: D002121:Calcium Channel Blockers; D015149:Tocolytic Agents; D008278:Magnesium Sulfate
keywords: Tocolytic therapy; beta-adrenergic agonist; calcium channel blocker; fetal heart rate variability; oxytocin receptor antagonist; prostaglandin antagonist