[The therapeutic role of tocolysis]

In twin pregnancies, the use of beta-adrenergics is associated with a significantly higher incidence of cardiovascular complications, and calcium channel blockers as well as oxytocin antagonists currently appear as first line agents. After extreme preterm delivery of the first twin and in selected patients, the birth of second twin may be delayed with a mean gain of 10-50 days. In cases of symptomatic placenta previa with mild-to-moderate bleeding, tocolytic agents may be associated with a prolongation of pregnancy and increased birth weight without significant impact on frequency or severity of bleeding. Calcium channel blockers are the drugs of choice in the event of diabetes. Indomethacin is a potent tocolytic, in particular in patients with polyhydramnios. However, it may cause oligohydramnios, premature closure of the ductus arteriosus and intrauterine fetal death when high doses are administered for a duration exceeding 48 to 72 hours, particularly beyond 32 weeks' gestation. The neonatal complications of indomethacin occur frequently. Tocolysis appears to reduce the failure rate of external cephalic version at term.