Transabdominal lidocaine to induce fetal demise: a cohort study

Abstract

Introduction We sought to assess the efficacy of transabdominal intrafetal lidocaine to achieve fetal demise before pregnancy termination. Methods This study was a retrospective cohort analysis of patients undergoing transabdominal intrafetal lidocaine injections prior to abortion procedures after 24 weeks from January 2018 to June 2020 at DuPont Clinic, an outpatient obstetrics and gynaecology clinic in Washington, DC, USA. We recorded data on maternal factors, gestational age, time of injection and fetal asystole, and injection dose and location. We defined successful intrafetal lidocaine injection as asystole achieved prior to the patient leaving the clinic. Results We performed injections in 338 fetuses in 335 patients, with a median gestational age of 27 weeks and 6 days (range 24-32 weeks). Lidocaine dose was 200-240 mg in 310 cases (91.7%) and 400-480 mg in 27 cases (8.0%) without difference in success (p>0.05). Lidocaine successfully induced fetal demise with one injection in 331 cases (97.9%). A second injection was required to induce demise for five fetuses (1.5%). Intracardiac injection was successful in 280 of 285 cases (98.3%), with asystole confirmed within 1 min in 75% of cases. Intrathoracic injection caused asystole in 45 of 47 cases (95.7%), with asystole confirmed within 2 min in 75% of cases. Success was not significantly associated with gestational age, body mass index or parity (p>0.05). One patient reported lidocaine-related side effects (0.3%). Conclusions Intrafetal lidocaine is a safe and effective method of inducing fetal demise. Intracardiac injection achieves fetal asystole almost immediately. Intrathoracic injection is also highly effective.