Table 3.

Incident risk ratio of miscarriage based on the number of short luteal phases in any of the 3 cycles prior to conception

# of short luteal phases < 10 days	Women	Miscarriages	Percent	IRR	95% CI
0	171	32	18.7%	1
1	59	13	22.0%	1.18	0.66	2.09
2	16	1	6.3%	0.33	0.05	2.29
3	5	2	40.0%	2.14	0.7	6.55