Objective: To assess the effect of variables that influence the pregnancy outcome of intrauterine insemination with frozen donor sperm.
Methods: A retrospective analysis of 408 cycles of frozen donor sperm inseminations were studied. Cycle fecundity and cumulative probability of pregnancy were compared according to several variables.
Results: The pregnancy rate was 13.5% per treatment cycle and 57.3% per patient. By life-table analysis, the cumulative probability of pregnancy was 75.6% after 12 cycle attempts, but there was a plateau after seven cycles. The cycle fecundity after the seventh cycle was 0.05, compared with 0.16 during the first seven cycles. Age had a profound impact on cycle fecundity. The cycle fecundity for women age 35 or less, 35-40, and over 40 years old were 0.2, 0.12, and 0.06, respectively. The cumulative probability of pregnancy after seven cycles for women 35 years or younger was 88%, compared with 65 and 42% in women 35-40 and over 40 years old, respectively. The number of motile sperm inseminated for pregnant cycles was higher than that for nonpregnant cycles. The fecundity rates for cycles with five or fewer, five to ten, greater than ten to 20, and over 20 million motile sperm inseminated were 5, 11, 16, and 20%, respectively.
Conclusion: The most significant predictors of the fertility of intrauterine insemination with frozen donor sperm were the women's age and the total number of motile sperm inseminated. Fecundity dropped after seven cycles of treatment.