Table 4.

Associations between multivitamin use, caffeine intake, alcohol use, smoking, and drug use and urinary tract infection in pregnancy—cross-sectional analysis of the National Birth Defects Prevention Study, 1997–2011.

	Total number	Reported UTI prevalence (%)	Crude prevalence ratio (95% CI)	Adjusted prevalence ratioa (95% CI)
Multivitamin use
Yes	38,612	18	1.00 (Reference)	1.00 (Reference)
No	2,973	21	1.16 (1.07, 1.24)	0.99 (0.92, 1.07)
Missing	284
Caffeine intake (mg/day)b
<10	6,934	16	1.00 (Reference)	1.00 (Reference)
10–99	14,531	18	1.15 (1.08, 1.23)	1.06 (0.99, 1.13)
100–199	9,856	18	1.15 (1.08, 1.24)	1.10 (1.02, 1.17)
200–299	5,180	19	1.19 (1.10, 1.29)	1.16 (1.07, 1.26)
≥300	4,477	22	1.38 (1.28, 1.50)	1.26 (1.16, 1.36)
Missing	891
Alcohol use
Yes	9,836	18	0.95 (0.91, 1.00)	1.02 (0.97, 1.07)
No	31,055	19	1.00 (Reference)	1.00 (Reference)
Missing	978
Smoking
Yes	7,113	24	1.42 (1.36, 1.49)	1.24 (1.18, 1.30)
No	33,954	17	1.00 (Reference)	1.00 (Reference)
Missing	802
Marijuana use
Yes	2,169	26	1.44 (1.34, 1.55)	1.05 (0.97, 1.13)
No	38,875	18	1.00 (Reference)	1.00 (Reference)
Missing	825
Cocaine use
Yes	319	30	1.64 (1.37, 1.93)	1.16 (0.97, 1.36)
No	40,732	18	1.00 (Reference)	1.00 (Reference)
Missing	818
Methamphetamine usec
Yes	250	29	1.57 (1.27, 1.88)	1.05 (0.85, 1.27)
No	41,131	18	1.00 (Reference)	1.00 (Reference)
Missing	488

CI, confidence interval; UTI, urinary tract infection.

^aAdjusted for birth defect status, study site, age at conception, race/ethnicity, educational attainment, and smoking during pregnancy.

^bUsual caffeine intake in the year before pregnancy.

^cThis variable was collected from free text. The number of missing values is the number of women who did not answer the question leading to the free text response.