HEMATOLOGICAL INDEXES AT FETAL BLOOD-SAMPLING IN MONOCHORIONIC PREGNANCIES COMPLICATED BY FETO-FETAL TRANSFUSION SYNDROME

36 MCDA twin pregnancies with FFTS investigated by fetal blood samplin g (FBS) were studied over a 10-year period (1988-1997). The haematolog ical data obtained at FBS were compared between the donor and recipien t fetuses. It was shown that the donor fetus had a significantly lower haematocrit (35.7 per cent versus 47.2 per cent; p<0.001), haemoglobi n (12.2 g/dl versus 15.8 g/dl; p<0.001), and red blood cell count (2.9 x 10(12)/l versus 3.8 x 10(12)/l; p=0.006) compared with the recipien t fetus. A haematocrit discordancy of >15 per cent, however, was found in only 25 per cent of twin pairs. There were no significant inter tw in differences in the remaining indices. The study concluded that alth ough there are significant differences in haematocrit and red cell mas s between the donor and recipient fetuses, only a minority of fetuses will have degrees of discordancy suggested in the literature to be dia gnostic. We suggest that FBS does not have a role in establishing the diagnosis of FFTS, although its role in determining the degree of haem atocrit discordancy to assist in timing of delivery remains to be eval uated. (C) 1998 John Wiley & Sons, Ltd.