Indications for tocolytic therapy: incidence of true preterm labor with uterine contractions as the sole deciding...

To evaluate the maximal impact tocolytic therapy could exert on preterm delivery rate, we conducted a retrospective study of all births that took place at Aarbus Kommune-hospital during a 2-year period when the only therapeutic regimen used in threatened preterm labor was bed rest. All singleton pregnancies that were delivered before the 35th week of gestation were included in the study. Eighty (1.2%) of 6454 deliveries fulfilled these criteria. Thirty-seven (46%) of the preterm pregnancies were associated with complications in which tocolytic therapy is contraindicated. Forty-three (54%) of the preterm deliveries occurred in women without pregnancy-related complications. Primary rupture of the membranes occurred in 19 (24%) women who therefore were not candidates for tocolytic therapy. Spontaneous contractions without contraindications for tocolytic therapy and with a cervical dilation less than 5 cm were present in 15 women only. In this group one infant had nonsuspected severe congenital malformations. Thus, only 14 (17.5%) of the preterm deliveries could have been prevented by tocolytic therapy. Tocolytic therapy other than bed rest was therefore indicated in only 0.2% of all deliveries.