Anovulations in an ovary during two menstrual cycles enhance the pregnancypotential of oocytes matured in that ovary during the following third cycle

The aim of this study was to test whether ovulation from an ovary affects t he health of oocytes from dominant follicles in that ovary two cycles later . A total of 80 women each with two intact ovaries underwent 270 treatment cycles (155 natural cycles and 115 clomiphene citrate cycles) all showing u nilateral ovulation. The results from the in-vitro fertilization (IVF) trea tment were grouped according to whether ovulation (O) or anovulation (A) (n o ovulation) was observed in the ovary with dominant follicle during the tr eatment cycle in the previous two cycles: O-O, A-O, O-A and A-A (previous s econd cycle-previous first cycle). The rate of pre-embryo formation in A-A was significantly higher than that of O-A. The pregnancy rate in A-A (29%) was also higher than those of O-A (13%), A-O (9%) and O-O (5%). These rates increased from O-O to A-A as the number of previous ovulations in an ovary decreased. The presence of a corpus luteum and/or a dominant follicle is l ikely to exert local negative effects on the health of the oocyte contained in the follicle selected to ovulate up to two cycles later. Anovulations i n an ovary for two menstrual cycles may therefore provide improved conditio ns for the development of a healthier oocyte with an increased pregnancy po tential.