Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion.
Twin-twin transfusion syndrome (TTTS) is a severe complication of monozygotic (identical) twin fetuses sharing one single (monochorionic) placenta. TTTS is caused by a net inter-twin transfusion of blood through placental anastomoses, from one twin (the donor) to the other (the recipient), which link the two feto-placental circulations. Currently, the only reliable method to measure the net inter-twin transfusion clinically is when incomplete laser therapy of TTTS occurs and one of the twins becomes anemic and requires an intra-uterine transfusion of adult red blood cells. Then, differences between adult hemoglobin concentrations measured during the transfusion and at birth relate not only to the net inter-twin transfusion but also to the finite lifetime of the adult red blood cells. We have analyzed this situation, derived the differential equations of adult hemoglobin in the donor and recipient twins, given the solutions and given expressions relating the net inter-twin flow with clinically measured parameters. We have included single and multiple intra-uterine transfusions. In conclusion, because incomplete laser therapy occurs frequently, and some cases require an intra-uterine transfusion, this method may allow collecting a wealth of net inter-twin flow data from clinicians involved in laser therapy of TTTS. To aid to the widespread use of this method, we have presented the equations as clearly as possible in tables for easy use by others.
van Gemert
Martin J C
MJ
Laser Centre and Department of Obstetrics, Laser Center, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. m.j.vangemert@amc.uva.nl
van den Wijngaard
Jeroen P H M
JP
Lopriore
Enrico
E
Pasman
Suzanne A
SA
Vandenbussche
Frank P H A
FP
D001163:Arteriovenous Anastomosis; D001703:Biophysics / Q000379:methods; D003198:Computer Simulation; D004200:Diseases in Twins; D005260:Female; D005330:Fetofetal Transfusion; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D053685:Laser Therapy; D007834:Lasers; D008954:Models, Biological; D015233:Models, Statistical; D011247:Pregnancy; D013997:Time Factors; D014427:Twins; D014430:Twins, Monozygotic
D006454:Hemoglobins