The effect of tocolytic use in the management of symptomatic placenta previa

The null hypothesis is that tocolysis has no effect on pregnancy prolongation in the aggressive expectant management of symptomatic preterm placenta previa.

One hundred twelve preterm pregnancies with confirmed placenta previa and an initial episode of acute vaginal bleeding were selected for this retrospective analysis. Exclusion criteria included gestational age > or = 35 weeks, delivery within 24 hours of admission, prior treatment for bleeding or preterm labor, and contraindications to tocolytic use. Tocolysis was prescribed, at the discretion of the treating clinical staff, in selected pregnancies with significant uterine contractions after admission of the patient. The majority of treated patients (85%) received intravenous magnesium sulfate and/or oral or subcutaneous beta-sympathomimetics within 24 hours of admission. Most patients remained hospitalized until delivery under this aggressive expectant management protocol. Both treated and untreated control study groups were similar at inclusion with regard to parity, gestational age, contraction frequency, and degree of initial bleeding. Outcome variables for each treatment group were obtained from final chart review. Continuous and categoric variables were compared with Student t test or chi 2 analysis-Fisher's exact test, respectively.

The clinical use of tocolysis in symptomatic placenta previa was associated with a clinically significant delay of preterm delivery. Significant improvement in clinical parameters such as interval from admission to delivery (39.2 vs 26.9 days, p < 0.02) and birth weight (2520 vs 2124 gm, p < 0.03) was observed in the tocolysis group. There was no observed statistical difference between the two treatment groups with regard to incidence of recurrent bleeding, interval from admission to first recurrent bleeding, and need for transfusion. There was a trend for patients with multiple bleeding episodes to have been receiving tocolytic therapy (p < 0.10). A trend for requiring a postpartum transfusion was also noted in the tocolysis group (p < 0.09). Treated pregnancies receiving long-term maintenance tocolysis with oral or subcutaneous terbutaline exhibited a greater degree of pregnancy prolongation than those treated with short-term intravenous magnesium alone (43.7 vs 15.3 days, p < 0.02).

This retrospective analysis suggests that tocolytic intervention in cases of symptomatic preterm previa may be associated with clinically significant prolongation of pregnancy and increased birth weight. Tocolytic therapy in these cases does not appear to have an impact on frequency or severity of recurrent vaginal bleeding. Further prospective analysis may delineate the role of tocolysis in the aggressive expectant management of symptomatic placenta previa.