Drugs used to induce fetal demise prior to abortion: a systematic review

Clinicians have used feticidal agents prior to second trimester abortion for many years. Despite the widespread use of various agents to induce fetal demise, a comprehensive or systematic review of the evidence is lacking on the safety, effectiveness, and most effective routes of administration.

To evaluate the existing drugs and routes of administration used in inducing fetal demise prior to abortion, and to determine the safety, effectiveness, and acceptability of these feticidal agents.

We searched PubMed, EMBASE, CINAHL, POPLINE, and Global Index Medicus to identify studies describing pharmacologic agents used to induce fetal demise prior to termination of pregnancy. We included randomized controlled trials and observational studies comparing digoxin, potassium chloride (KCL), and lidocaine to induce fetal demise. We included studies that evaluated the primary outcomes of safety and effectiveness, including success in achieving fetal demise, induction to expulsion time for medical abortion, dilation and evacuation time, as well as maternal side effects and complications. Two authors independently screened abstracts and full texts. One reviewer extracted data from the included studies, which was counterchecked by a second reviewer.

We identified eight studies that met inclusion criteria: three randomized controlled trials, and five observational studies. A total of 4505 women received drugs to induce fetal demise at 17 to 38 weeks' gestation, including digoxin (n = 4174), KCL (n = 324), and lidocaine (n = 7). Intra-fetal digoxin was superior to intra-amniotic digoxin in achieving fetal demise (OR 3.51, 95% CI 1.60, 7.78). Intracardiac KCL 15% 2-3 mL reduced induction to expulsion time by 320 min (p <.006).Similarly, intracardiac KCL 15% 1-3 ml reduced dilation and evacuation time from 16.1 ± 7.9 min to 12.7 ± 5 min (p < 0.001). Intracardiac lidocaine 2% 10 mL was more effective at achieving fetal demise than intracardiac KCL 6 mmol (85.7% vs. 57.9%). Intra-amniotic and intra-fetal digoxin 1 mg, as compared to no feticidal agent, led to greater pre-procedure expulsion, hospital readmission, and the presence of one or more signs of infection.

Evidence from included cohort studies demonstrates that digoxin, KCL, and lidocaine are all effective in inducing fetal demise. Intra-fetal administration of digoxin is superior to intra-amniotic digoxin administration. Administration of feticide using intracardiac KCL may shorten the abortion experience. Limited data from observational studies also supports an increase in maternal side effects and/or complications related to the administration of digoxin.

Intra-fetal administration of digoxin is more effective in achieving fetal demise when compared to intra-amniotic administration. There is a knowledge gap in determining the single best drug for inducing fetal demise prior to abortion. Additional research is needed to compare different feticidal agents in terms of safety and effectiveness.