Changes in caffeine consumption as a signal of pregnancy

Objectives: The purpose of this prospective study was to examine caffeine consumption and other signals of early pregnancy. Study Design: One hundred and five pregnant, nonsmoking, coffee drinkers ages 18-40 were enrolled by the ninth week after their last menstrual period (LMP). Participants kept daily diaries of beverage and caffeine consumption and symptoms. Urine samples were collected to assess hormone metabolites. Descriptive statistics were generated. Results: During the first trimester, 96% of subjects decreased or quit drinking coffee, 65% of whom reported a unique aversion to coffee. The mean daily caffeine consumption at LMP from coffee alone was 119 mg (S.D., 105), with a range 1-574 mg. There was a 59% decrease of mean daily consumption of caffeine from coffee between weeks 4 and 6, from 96 to 39 mg. The vast majority of subjects experienced nausea (98%) and appetite loss (93%); vomiting was less prevalent (54%). The most common dietary aversions included meat, coffee, spicy foods, and dairy products. Hormone metabolite patterns are reported. Conclusion: Signals of early pregnancy included an aversion to coffee in addition to nausea and vomiting, which resulted in decreased caffeine consumption. These symptoms often interfered with daily life and lasted beyond the first trimester for many. Consideration should be given that a decrease in caffeine consumption may be a signal for a healthy pregnancy and acting as a confounder. (C) 2004 Elsevier Inc. All rights reserved.