Objective: Feticide may be achieved by the injection of strong potassium chloride (KCl) into the fetal circulation via the cardiac route, or less frequently, into the umbilical cord. Despite the relative frequency of this procedure, little published information is available on the subject.
Subjects and methods: This was a retrospective analysis of all feticide procedures carried out prior to legal pregnancy termination in mid trimester of pregnancy from January 1996 to July 2001, in a tertiary fetal medicine referral center. The effect of gestational age and the route of access to fetal the circulation on the dose of strong KCl required to achieve cardiac asystole was evaluated.
Results: A total of 106 women underwent the procedure of feticide during the study period. Gestational age had no effect on the dose of strong KCl. The median dose of KCl administered by cordocentesis (5 mL) was significantly less (P < 0.001) than the dose required when fetal cardiocentesis was performed for administration of the drug (10 mL).
Conclusion: This is the first comparative study of feticide by the administration of strong KCl by fetal cardiocentesis and cordocentesis. The study demonstrates that both cardiac and umbilical routes can be used to achieve feticide effectively, without compromising maternal safety. A finding of this study is that significantly smaller doses of KCl were required to achieve fetal cardiac asystole when using the umbilical compared to the cardiac route, although this may be explained by differences in technique. Strong 15% KCl can safely be used to achieve feticide in volumes up to 20 mL for cardiocentesis and 8 mL for cordocentesis.