Table 2.

Adjusted fecundability ratios for caffeinated beverage intake among 2135 female pregnancy planners, PRESTO, 2013-16.

	Baseline Beverage Data			Time-Varying Beverage Data
Exposure	No. of Pregnancies	No. of Cycles	Adjusted^a FR (95% CI)	No. of Pregnancies	No. of Cycles	Adjusted^a FR (95% CI)
Caffeine (mg/day)
<100	642	4698	Reference	691	4915	Reference
100-199	466	3298	1.06 (0.94, 1.18)	443	3223	0.99 (0.88, 1.10)
200-299	147	1159	0.98 (0.83, 1.17)	131	1021	0.93 (0.78, 1.11)
≥300	63	498	1.15 (0.90, 1.48)	53	494	0.90 (0.69, 1.18)
Regular coffee (cups/day)^b
0	436	3271	Reference	489	3364	Reference
<1	363	2946	0.97 (0.85, 1.10)	338	3007	0.82 (0.72, 0.94)
1	406	2523	1.21 (1.06, 1.37)	394	2428	1.09 (0.96, 1.24)
≥2	113	913	1.02 (0.84, 1.25)	97	854	0.84 (0.68, 1.03)
Black tea (cups/day)^b
0	942	7026	Reference	964	7078	Reference
<1	291	1933	1.08 (0.96, 1.22)	272	1916	1.07 (0.93, 1.23)
1	61	442	1.06 (0.83, 1.34)	62	428	1.16 (0.88, 1.52)
≥2	24	250	0.85 (0.58, 1.25)	20	231	0.89 (0.53, 1.48)
Green tea (cups/day)^b
0	981	7271	Reference	1006	7422	Reference
<1	287	2018	1.03 (0.92, 1.17)	268	1891	1.06 (0.92, 1.22)
≥1	50	364	0.98 (0.76, 1.28)	42	340	0.97 (0.72, 1.32)
Caffeinated soda (cans/day)^b
0	712	4802	Reference	6787	5530	Reference
<1	501	3836	0.95 (0.86, 1.06)	407	3118	0.98 (0.84, 1.16)
1	73	725	0.85 (0.68, 1.07)	87	641	0.76 (0.57, 1.01)
>2	32	290	0.92 (0.66, 1.28)	37	364	1.09 (0.66, 1.79)
Energy drinks (servings/day)^b
0	1226	8838	Reference	1232	8892	Reference
>0	92	815	0.93 (0.76, 1.14)	86	761	0.95 (0.77, 1.17)

Adjusted for age, race/ethnicity, education, BMI, smoking history, alcohol intake, intercourse frequency, doing something to improve chances of conception, average nightly sleep, perceived stress scale score, and average work time.

Additionally adjusted for other caffeinated beverages.