Objective: The purpose of this study was to determine the safety of intra-amniotic digoxin injection before late second-trimester pregnancy termination by dilation and evacuation through an assessment of maternal systemic digoxin absorption, cardiac rhythm, and coagulation parameters.
Study design: Pregnant women at between 19 and 23 weeks' gestation received 1.0 mg digoxin through intra-amniotic injection and then had serum digoxin levels determined for 48 hours and Holter cardiac monitoring performed for 24 hours. Clotting parameters were assessed before digoxin injection and 24 hours later, at the time of the dilation and evacuation procedure.
Results: Eight patients completed the study. The mean (+/-SD) serum digoxin peak concentration was 0.81 +/- 0.22 microg/L (range, 0.5-1.1 microg/L). The mean (+/-SD) time to peak digoxin concentration was 11.0 +/- 5.55 hours (range, 4-20 hours). Ambulatory cardiac monitoring showed no rhythm or conduction abnormalities associated with digoxin. Prothrombin time, partial thromboplastin time, and fibrinogen levels did not change significantly between determinations before and after the dilation and evacuation procedure (11.5 to 11.4 seconds, 24.1 to 24.4 seconds, and 441 to 475 mg/dL, respectively).
Conclusion: The maximum digoxin concentration peak achieved after intra-amniotic injection was in the low therapeutic range. No rhythm or conduction abnormalities associated with digoxin were noted by Holter monitoring. Coagulation parameters did not change significantly. On the basis of the limited systemic absorption and the absence of clinically significant cardiac or clotting effects, intra-amniotically administered digoxin may be considered safe for use before late second-trimester pregnancy terminations.