Case Report: Sequential fetal reduction in a triplet pregnancy and its effects on coagulation balance

Over the last few decades, the increase in medically assisted reproduction has led to a significant increase in the frequency of twin and higher-order multiple pregnancies (defined as triplets or more). A critical element of this trend is the increased risk of preterm birth and infant mortality in twin and higher-order pregnancies. Fetal reduction (FR) was initially established as an option to reduce these adverse outcomes. Indications for FR have now expanded, with literature indicating clear improvement of outcomes after reduction to twins or singletons from triplet pregnancies, although physiological adaptations during pregnancy following FR have not been thoroughly investigated. One clinically relevant research gap is the effect of FR on coagulation and fibrinolysis, given that pregnancy is associated with a hypercoagulable state. In this novel case study, our objective was to characterize the hemostatic impact of FR. We employed a functional assay, thromboelastography (TEG), to compare the maternal hemostatic function in a triplet pregnancy that was sequentially reduced to a singleton pregnancy with uncomplicated singleton pregnancies. Patient 611 became pregnant during her fourth cycle of intrauterine insemination, and a dating ultrasound confirmed a trichorionic triamniotic triplet pregnancy. After counseling, the patient chose to undergo fetal reduction to a singleton pregnancy. Both reductions were achieved via the injection of potassium chloride. TEG was performed on blood samples taken during pregnancy, and patient 611 was compared with patients with singleton pregnancies who had also undergone ovulation induction at similar gestational ages. We observed an overall decrease in coagulability across all TEG parameters from prepregnancy to term in patient 611 compared with that in control singleton pregnancies. These data suggest that fetal reduction may limit the pregnancy-associated hypercoagulable states.