Second trimester amniocentesis in twin pregnancies: maternal haemoglobin as a dye marker to differentiate diamniotic twins

OBJECTIVE: To review the use of a membrane-free haemolysate prepared from maternal blood to distinguish the amniotic sacs at amniocentesis in twin gestation. SETTING: University Hospital, Groningen. METHOD: Haemoglobin solution prepared from maternal blood. SUBJECTS: 63 twin pregnancies having amniocentesis. RESULTS: The fetal loss before 28 weeks was 4%. There was no perinatal mortality. Dye was detected in the second sac in 9 of 24 women tested before 1985 and none of the 39 women since, no malformations could be ascribed to the use of the haemolysate. CONCLUSION: The use of the membrane-free haemolysate is safe, but the technique will probably gradually become redundant because of improved ultrasound.