Maintenance tocolysis between clinical practice and evidence-based medicine

The primary aim of tocolytic treatment in cases of preterm labour is to prolong pregnancy for at least 48 hours in order to complete the administration of corticosteroids for lung maturation and to transfer the patient to a tertiary center. Women who are undelivered after 48 hours of tocolysis remain at increased risk for the recurrence of preterm labour. Most obstetricians continue tocolytic therapy beyond 48 hours, particularly, if preterm labour persists; but it is not clear whether prolonged treatment ("maintenance tocolysis") has a significant effect on perinatal and neonatal outcome. In the hope of maintaining uterine quiescence, at least 12 different tocolytics have been investigated in numerous clinical trials. Systematic reviews and meta-analysis of the literature clearly show that maintenance tocolysis has no significantly beneficial effect on the incidence of preterm delivery, incidence of preterm labour recurrence, birth weight of the baby and perinatal and neonatal morbidity and mortality. According to current international guidelines, maintenance therapy can not be recommended for routine use. The guidelines of the German Society of Obstetrics and Gynecology came to the conclusion that maintenance tocolysis should be considered in cases of preterm labour and very early gestation (< 30 weeks gestation) and in cases of "symptomatic" placenta praevia. Irrespective of the data from evidence-based medicine maintenance tocolysis remains a challenge to the obstetrician and requires an individual decision which is influenced by several other medical and non-medical factors.