Kobayashi S, et al. - Using adjusted multiple linear regression and Cox regression models, researchers investigated dose-dependent associations in the Japan Environment and Children's Study between prenatal caffeine consumption and small for gestational age, preterm birth and reduced birth weight. Study participants included 94,876 fetuses in Japan. According to self-administered questionnaires, the median estimated consumption of caffeine during pregnancy was 125.5 mg/day. According to this prospective birth cohort, prenatal consumption of caffeine was linked to birth size. However, since the association between prenatal caffeine consumption and birth size was probably confounded by unforeseen potential factors, their trust in the association's true causality is moderate.