Table 3.

Modeled fit between age and time to pregnancy, with fecundability ratios and 95% confidence intervals, using separate models for females and for males.

Age (y)	Pregnancies	Cycles	Unadjusted model		Adjusted model^a
Age (y)	Pregnancies	Cycles	FR	95% CI	FR	95% CI
Females
20–24	314	2035	1.00	(ref.)	1.00	(ref.)
25–29	996	5734	1.12	0.99, 1.25	1.03	0.90, 1.18
30–34	625	3115	1.26	1.12, 1.43	1.05	0.89, 1.23
35–40	140	948	0.97	0.81, 1.16	0.77	0.62, 0.97
Males
20–24	135	916	1.00	(ref.)	1.00	(ref.)
25–29	747	4453	1.13	0.95, 1.33	1.05	0.87, 1.26
30–34	817	4186	1.27	1.08, 1.50	1.09	0.90, 1.32
35–39	283	1680	1.12	0.93, 1.36	0.96	0.77, 1.19
≥40	93	597	1.04	0.82, 1.33	0.95	0.73, 1.25

Note: FR = fecundability ratio, CI = confidence interval. Unadjusted model controls for cycle number.

Model is adjusted for cycle number, age of the female or male partner (yr), vigorous physical activity (y/n), BMI, vocational training (y/n), alcohol consumption (y/n), current smoking (y/n), pack-years of smoking (ever smokers), partner smoking (y/n), partner BMI, parity, cycle length (days), cycle regularity (y/n), intercourse frequency (no./wk), last method of contraception (barrier/hormonal/other), and methods used to time intercourse (basal body temp/LH ovulation test kit/other).