Side of ovulation and cycle characteristics in normally fertile women.

This study was undertaken to establish whether ovulation in humans alternates consistently from right to left ovary in successive cycles and whether the site of ovulation affects the next cycle length or the hormonal profiles. A total of 199 cycles in 80 normally fertile women were studied. The volunteers were monitored with ultrasonography to determine the day and side of ovulation and to calculate follicular and luteal phase lengths. Urinary hormone concentrations were also assayed. Right-sided ovulations occurred in 104 of the 199 cycles (52.3%; not significantly different from 50%). Alternate ovulations occurred in 61 of the 119 pairs of succeeding cycles (51.3%, not significant). The follicular phase length in contralateral ovulation (14.59 +/- 0.33 days; mean +/- SEM) did not differ significantly from that of ipsilateral ovulation (14.59 +/- 0. 37 days). There were also no significant differences in urinary concentrations of oestrone-3-glucuronide, pregnanediol-3alpha glucuronide, follicle stimulating hormone, and luteinizing hormone between ipsilateral and contralateral ovulation in either early follicular, peri-ovulatory or luteal phase of the cycle. It is concluded that in normally fertile women, the cycle length and the hormonal profile are independent of the, most probably random, site of ovulation.