The interval to spontaneous delivery following discontinuation of maintenance tocolysis

To determine the interval to spontaneous delivery following discontinuation of continuous subcutaneous terbutaline (SQT).

Singleton and twin gestations receiving outpatient preterm labor management services with SQT were identified from a database. Patients having SQT discontinued at 33.0-35.9 weeks (in a stable condition, not hospitalized and with known cervical status at discontinuation) with subsequent spontaneous labor and delivery were included (n = 1420). Data were compared by gestation type, week of SQT discontinuation and cervical dilatation using Kruskal-Wallis and Fisher's exact test analyses (p < 0.05 statistically significant).

Spontaneous preterm delivery occurred in 63.0% of singletons and 87.9% of twins. Although stable at SQT discontinuation, 32.5% of singletons and 59.9% of twins delivered within three days. The interval from discontinuation of SQT to delivery was less for twin than singleton gestations (5.1 +/- 6.5 vs. 11.0 +/- 10.5 days, respectively, p < 0.001). CONCLUSIONS. Preterm discontinuation of SQT should be avoided if additional pregnancy prolongation is desired.