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Effect of tocolytic drugs on fetal heart rate variability: a systematic review

Kim M J Verdurmen¹, Alexandra D J Hulsenboom¹, Judith O E H van Laar¹

¹a Department of Obstetrics and Gynecology , Máxima Medical Center , Veldhoven , the Netherlands and.

The Journal of Maternal-Fetal & Neonatal Medicine : the Official Journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians

|October 21, 2016

Abstract

Introduction:

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.

Materials And 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.

Conclusion:

In order to prevent iatrogenic preterm labor, the effects of tocolytic drugs on fetal HRV should be taken into account when monitoring these fetuses.

Keywords:

Tocolytic therapy beta-adrenergic agonist calcium channel blocker fetal heart rate variability oxytocin receptor antagonist prostaglandin antagonist

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