Fertility after simulated Fowler-Stephens orchiopexy in rats.

In order to determine the effects of the Fowler-Stephens orchiopexy (FSO) on fertility, young rats underwent simulated FSO, FSO and concurrent contralateral orchiectomy (FSO/OR), unilateral orchiectomy (OR), or sham operation (controls). Twelve weeks after the operation, each male rat was mated to two proven-fertile female rats for 17 days (three ovulatory cycles). Two weeks later, both male and female rats were killed. No pregnancy resulted from the matings of the FSO/OR males. In contrast, pregnancy ensued in 13 of 16 (81%) females in the FSO group, 9 of 14 (64%) in the OR group, and 11 of 12 (92%) in the control group. There were no fertile males in the FSO/OR group. In the FSO group, eight of eight males induced pregnancy in at least one female; in the OR group, six of seven (86%) males were fertile as were all six males in the control group. No differences in litter size or fetal weight were observed between fertile females in various groups.