Pregnancy rate in timed-mated, spontaneously cyclic rhesus monkeys, Macaca mulatta

After detection of the preovulatory oestradiol-17 beta peak in blood, females were placed with a male and left undisturbed during mating (N = 28, 94 cycles) or were exposed to serial diagnostic laparoscopy (1-4 occasions) to monitor ovulation (N = 87, 224 cycles). A total of 86 pregnancies resulted from timed mating in the 318 menstrual cycles (27% rate). When periovulatory laparoscopy was performed, the pregnancy rate was 22.3%. In the absence of laparoscopy the pregnancy rate was 38.3% (P less than 0.003). These pregnancy rates are similar to those of women and show an adverse effect of laparoscopy on pregnancy rate.