Abstract: Objective: To investigate the correlation between the surgical timing of insemination and the pregnancy rate of intrauterine artificial insemination （ＩＵＩ）. Methods: The retrospective analysis was designed in 851 infertile couples with male factors who were treated with IUI （a total of 1 751 cycles）. Those cycles were divided into four groups as follows: Group 1 was one time of IUI before ovulation, Group 2 was one time of IUI after ovulation, Group 3 was two times of IUI before ovulation, and Group 4 was two times of IUI before and after ovulation individually. The pregnancy rates of four groups were then compared accordingly. Results: The pregnancy rates in group 1 and group 2 were 11.21% and 12.23%, while in group 1 the pregnancy rate in couples with ovulation after IUI was significantly higher than that in those couples with anovulation（P＜0.05）. The pregnancy rates in group 3 and group 4 were 16.21% and 15.65%, while in group 3 the pregnancy rate in couples with ovulation after IUI was significantly higher than that in those couples with anovulation （１7.14% vs. 0.00%, P=0.040）. In the ovulatory cycles of four groups, the pregnancy rates were 10.99%, 12.23%, 17.14% and 16.21% respectively（P＞0.05）. The pregnancy rate of two times of IUI was higher than that of one time of IUI （although P＞0.05）. Conclusions: There are not significant difference in the pregnancy rate in those couples with ovulation before or after IUI treatment, 1 or 2 times of IUI. However, the pregnancy rate is very low in those couples without ovulation before or after IUI treatment (0~2.85%). Those women with the luteinized unruptured follicle syndrome （ＬＵＦＳ） ｄｕｒｉｎｇ ｔｗｏ ｃｙｃｌｅｓ ｏｆ ＩＵＩ ｓｈｏｕｌｄ ｂｅ ａｄｖｉｓｅｄ ｔｏ ｔｒｅａｔ ｗｉｔｈ ｉｎ ｖｉｔｒｏ ｆｅｒｔｉｌｉｚａｔｉｏｎ （ＩＶＦ）．

Key words: Insemination, artificial, Insemination, artificial, homologous, Pregnancy rate, Uterus