Table 1.

Cumulative probability of conceiving a clinical pregnancy by the number of menstrual cycles

Age category, years	Pregnant after 1 year (12 cycles), %	Pregnant after 2 years (24 cycles), %
19–26	92	98
27–29	87	95
30–34	86	94
35–39	82	90

From NICE guideline 156. Cumulative probability of conceiving a clinical pregnancy by the number of menstrual cycles attempting to conceive in different age categories (assuming vaginal intercourse occurs twice per week) (Reproduced with permission: Dunson DB, Baird DD, Colombo B [2004]. Increased infertility with age in men and women. Obstetrics and Gynecology 103: 51–6).