A Danish national cohort of 730 infants born after intracytoplasmic sperm injection (ICSI) 1994-1997.

This national cohort study included all clinical pregnancies obtained after intracytoplasmic sperm injection (ICSI) registered in Denmark between January 1994 and July 1997 at five public and eight private fertility clinics. Laboratory and clinical data were obtained from the fertility clinics. The couples answered a questionnaire regarding the pregnancy and the health of the child (response rate 94%). Data validation was carried out through discharge charts. The mean age of the women was 32.1 years. In 84.2% of couples, male factor was the main reason for performing ICSI, and in 4.8% epididymal spermatozoa were used. The mean number of embryos replaced was 2.3 (range 1-3) and in 95% of cases fresh embryos were transferred. Only 183 women (28.5%) underwent prenatal diagnosis, resulting in 209 karyotypes with seven (3.3%) chromosome aberrations. Six major chromosomal abnormalities (2.9%) and one inherited structural chromosome aberration (0.5%) were found, but no sex chromosome aberrations. The frequency of multiple birth, Caesarean section rate, gestational age, preterm birth, and birth weight were comparable with previous studies. The perinatal mortality rate was 13.7 per 1000 children born with a gestational age of 24 weeks or more. In 2.2% (n = 16) of the liveborn infants, and in 2.7% (n = 20) of all infants, major birth defects were reported by the parents. Minor birth defects were found in nine liveborn infants (1.2%). In conclusion, the results of this study on outcome of ICSI pregnancies are in line with earlier reports, except that no sex chromosome abnormalities were found.