THE APPLICABILITY OF THE CUMULATIVE EMBRYO SCORE SYSTEM FOR EMBRYO SELECTION AND QUALITY-CONTROL IN AN IN-VITRO FERTILIZATION-EMBRYO TRANSFER PROGRAM

The cumulative embryo score system involves three aspects of relevance in pregnancy achievement during in-vitro fertilization (IVF) and embr yo transfer: cleavage rates, morphological qualities and the number of embryos transferred. The scores of 602 IVF/embryo transfer trials wer e calculated and analysed to determine the system's relationship to pr egnancy rate, pregnancy outcome and the incidence of twin and triplet pregnancies. The system was also applied to cycles where endotoxins we re either present in or absent from culture medium, in order to evalua te its validity in quality control analyses. Pregnancy rates were foun d to increase from 4%, with scores between 1 and 10, to 35% in the 41- 50 group. The score of 20 was the criterion for separating patients in to poor and good pregnancy prognosis groups (P = 0.00001). Biochemical abortions occurred more frequently with scores < 20 (P = 0.00978), bu t a similar relationship was not found in clinical abortion rates (P = 0.62206). Birth rates below and above a score of 20 (2.8 and 19.2%, r espectively) differed significantly (P = 0.0005). The scores of twins overlapped extensively with those of singleton births, but those of al l triplets were > 40. The system did not reflect a correlation between embryo quality and the presence of endotoxins in culture medium.