A total of 344 pregnancies — from 501 couples in Texas and Michigan — were tracked between 2005 and 2009, with 98 resulting in a miscarriage. Caffeine use wasn't the only thing tracked during the study, researchers also monitored the couples' use of multivitamins, alcohol and cigarettes.
The research wasn't all bad, however. The study showed that prenatal multivitamins had a positive link with pregnancies.
Women who took a daily vitamin in the weeks leading to conception had a 55 percent lower risk for a miscarriage — and the risk lowered even more for women who continued taking vitamins into their pregnancy.
Clint Davis is a writer for the Scripps National Desk. Follow him on Twitter @MrClintDavis.