Assisted reproductive technology in Europe, 2000. Results generated from European registers by ESHRE

European results of assisted reproductive techniques from treatments initiated during 2000 are presented in this fourth annual report. Data were collected mainly from pre-existing national registers. From 22 countries, 569 clinics reported 279 267 cycles: IVF 126 961, ICSI 99 976, frozen embryo replacement (FER) 45 800 and oocyte donations (OD) 6530. In nine countries where all clinics reported to the register, a total of 142 174 cycles were performed in a population of 166 million, corresponding to 856 cycles per million inhabitants. After IVF and ICSI, the distribution of transfer of one, two, three and greater than or equal to4 embryos was 12.1, 46.7, 33.3 and 6.8%, respectively. Huge differences existed between countries. For IVF, the clinical pregnancy rate per aspiration and per transfer was 24.7 and 28.4%, respectively. For ICSI, the corresponding rates were 26,6% and 28,7%. These figures represent increases of 0.7 and 0.8% compared with 1999. The distribution of singleton, twin, triplet and quadruplet deliveries for IVF and ICSI combined was 73.6, 24.4, 2.0 and 0.04%. This gives a total multiple delivery rate of 26.4%. The range of triplet deliveries after IVF and ICSI ranged from 0.3 to 7.0% between countries. Compared with 1999, the number of reported cycles was increased by 8% and the clinical pregnancy rate per transfer was increased by 0.7% after IVF and by 0.8% after ICSI. The total multiple delivery rates after IVF and ICSI remain unchanged during the last 4 years.