Effect of changing sperm donor in the second treatment cycle on the rates of pregnancy, live birth and miscarriage.

Women with longer exposure to paternal antigens, such as a long duration of sexual cohabitation, are known to have a higher chance of successful placentation. However, it is still unknown how repeated exposure to the same sperm donor affects the outcome. We have studied the rates of pregnancy, live birth, and miscarriage among 1077 women undergoing IUI or IVF/ICSI, using either the same donor during two consecutive treatment cycles or two separate donors. Oocyte donation and frozen embryo transfer cycles were excluded. No difference was found either in pregnancy rate or live birth rate when comparing repeated treatments with the same donor (n = 815) to treatments with two separate donors (n = 262) (success rate (SR) 0.96, 95 % CI 0.75-1.23, p = 0.75; SR 1.18, 95 % CI 0.84-1.65, p = 0.33, respectively). A significant difference in miscarriage rate was observed (relative risk (RR) 0.58, 95 % CI 0.35-0.96, p = 0.03). However, after adjusting for treatment method, maternal age, BMI, and individual clinic, no significant differences were observed in any of the outcomes: pregnancy rate (adjusted SR 1.05, 95 % CI 0.79-1.39, p = 0.76), live birth rate (adjusted SR 1.20, 95 % CI 0.83-1.73, p = 0.33), or miscarriage rate (adjusted RR 0.61, 95 % CI 0.33-1.12, p = 0.11). Consequently, this study could not demonstrate any advantageous effects of repeatedly using the same sperm donor on pregnancy rate or live birth rate. However, given the limited sample size, an effect on the miscarriage rate cannot be ruled out.