A cohort of 485 couples starting their first in-vitro fertilization (IVF) attempt between January, 1989 and February, 1991 inclusive, were followed until June 1, 1992. A total of 1086 treatment cycles were initiated (mean 2.2, range 1-6). Of these, 235 (21.8%) cycles were cancelled, giving a total of 851 embryo replacements (mean 1.7, range 1-5). After IVF treatment, 189 women have either delivered or have an ongoing pregnancy in the second or third trimester. This gives a baby take-home rate of 17.4% per started cycle and 22.2% per embryo replacement. For 91 (18.6%) of the couples, the treatment was abandoned prior to completion of the three scheduled IVF attempts and 57 (11.7%) of these had no completed IVF cycles. In the group of couples with reduced sperm quality, the delivery rate was significantly lower than that of the other groups. A total of 193 women had embryos cryopreserved in at least one IVF cycle; 124 of these women started a frozen embryo replacement cycle and 88 had at least one cycle with replacement of frozen/thawed embryos, resulting in 25 deliveries/ongoing pregnancies. Due to the Norwegian law on assisted procreation 65 (33.7%) of the women have had their frozen embryos thawed and discarded after 12 months of storage. The cryopreservation programme, with the limitations of the Norwegian law, gives a 5.2% increase in the baby take-home rate for women entering the IVF programme, an increase of 13.2% in the number of ongoing pregnancies/deliveries and an 11.6% increase in number of children/viable fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)