Insemination can be performed at various time points around ovulation and can be performed once or many times. In most published studies, insemination is performed after 32 – 36h hCG administration. Given that the timing of insemination relative to ovulation is the key to the optimal success rate, few studies aim to find the optimal timing for insemination is quite surprising. A systematic review found that there was no difference in pregnancy rates for every two fertilized couples compared to a single fertilization
