Table 2.

Menstrual cycle characteristics according to date of EC relative to expected ovulation: pre-ovulatory >2 days before ovulation, peri-ovulatory=from 2 days before to 2 days after ovulation, post-ovulatory >2 days after ovulation

	Pre-ovulatory EC (n=64 for EC cycle, n=32 for post-EC cycle)	Peri-ovulatory EC (n=90 for EC cycle, n=56 for post-EC cycle)	Post-ovulatory EC (n=78 for EC cycle, n=44 for post-EC cycle)
Cycle length (mean days)
Baseline	28.8	29.2	27.2
EC cycle	28.0†	29.2	28.9†
Post-EC cycle	28.5	29.3	27.3†
Menstrual period duration (mean days)
Baseline	4.3	3.9	3.9
EC cycle	4.5	4.3†	4.2†
Post-EC cycle	4.4	4.4†	4.3†
Dysmenorrhea (incidence)
Baseline	0.43	0.56	0.59
EC cycle	0.28†	0.60	0.42†
Post-EC cycle	0.5	0.59*	0.27*

^*p<0.05 for comparison with baseline compared to baseline by paired t-test or McNemar’s paired chi-square test

^†p<0.01 for comparison with baseline compared to baseline by paired t-test or McNemar’s paired chi-square test