Assisted reproductive technology in Europe, 2001. Results generated from European registers by ESHRE

European results of assisted reproductive techniques from treatments initiated during 2001 are presented in this fifth report. Data were collected mainly from already existing national registers. From 23 countries, 579 clinics reported 289 690 cycles with: IVF 120 946, ICSI 114 378, frozen embryo transfer (FER) 47 195 and egg donation (ED) 7171. Overall this represents a 4% increase since the year 2000. For the first time, results on European data on intra-uterine inseminations (IUIs) were reported from 15 countries. A total of 67 124 cycles [IUI husband'sperm (IUI-H) 52 949 and IUI donor sperm (IUI-D) 14 185] were included. In 12 countries where all clinics reported to the register, a total of 108 910 cycles were performed in a population of 131.4 million, corresponding to 829 cycles per million inhabitants. For IVF, the clinical pregnancy rate per aspiration and per transfer was 25.1 and 29.0%, respectively. For ICSI, the corresponding rates were 26.2 and 28.3%. These figures are similar to the results from 2000. After IUI-H, the clinical pregnancy rate was 12.8% in women < 40 and 9.7% in women >= 40 years of age. After IVF and ICSI, the distribution of transfer of one, two, three and >= 4 embryos was 12.0, 51.7, 30.8 and 5.5%, respectively. Compared with the year 2000, fewer embryos were transferred, but huge differences existed between countries. The distribution of singleton, twin and triplet deliveries for IVF and ICSI combined was 74.5, 24.0 and 1.5%, respectively. This gives a total multiple delivery rate of 25.5%, compared with 26.9% in the year 2000. The range of triplet deliveries after IVF and ICSI differed from 0.0 to 8.2% between countries. After IUI-H in women < 40 years of age, 10.2% were twin and 1.1% were triplet gestations.