Does caffeine consumption during pregnancy increase the risk of fetal mortality? A literature review

Abstract

The aim of this study was to evaluate the available epidemiological evidence of the effect of caffeine consumption during pregnancy on fetal mortality. A systematic qualitative review of observational studies that referred to any source of exposure to caffeine from food in pregnancy and to fetal mortality as the outcome was conducted in the databases MEDLINE and LILACS. Studies published between January 1966 and September 2004 were searched. The following descriptors were used: "caffeine", "coffee", "tea", "cola", and "cacao" to define the exposure and "fetal death", "stillbirth", "fetal demise", and "fetal loss" to define the outcome. The search strategy retrieved 32 publications, but only six met the inclusion criteria and three were included. One more article was found using "see related articles" feature in PubMed. A total of four publications were included in the review. The small number of publications addressing this subject, methodological limitations, inaccurate exposure assessment in all the studies, overall risks only marginally significant in most cases, and the possibility of publication bias preclude stating with certainty that caffeine consumption is actually associated with fetal death.

Maternal caffeine intake during pregnancy and risk of pregnancy loss: a categorical and dose–response meta-analysis of prospective studies

“…However, our results should be interpreted with caution in consideration of methodological limitations of the original studies and other potential issues such as residual confounding and publication bias that may have influenced our results. Most previous reviews on maternal caffeine intake and pregnancy loss included only a qualitative summary of the evidence (17,48,49) , used estimates that were not adjusted for potential confounders (50) or included only five studies on preconception caffeine intake (51) . A recent meta-analysis reported significant associations stronger than those observed in our meta-analysis between higher maternal caffeine intakes and higher risks of miscarriage (summary RR = 1·14 per 100 mg caffeine/d, 95 % CI 1·10, 1·19 in that study compared with 1·08, 95 % CI 1·04, 1·13 in our study) and stillbirth (summary RR = 1·19, 95 % CI 1·05, 1·35 in that study compared with 1·09, 95 % CI 1·02, 1·16 in our study) (18) .…”

Effects of Sri Lankan Black Tea (Camellia sinensis L.) on Pregnancy of Rats

“…Theoretically, at the highest dose of black tea brew tested in this study, caffeine concentration would be approximately 865 mg. A normal tea cup is considered to be 170 ml and contains 50 mg of caffeine [2,6]. Caffeine is known to cross the placental barrier [7] and concentrations of this magnitude are likely to produce deleterious effects on pregnancy outcome and pre‐ and early postnatal development of offspring [1,4–7] with malformations in limbs and palate [15]. In addition, high caffeine concentrations are also known to increase the risk of developing sudden infant death syndrome in human babies [15].…”

“…This includes a variety of water soluble phytochemicals constituents such as flavonols (polyphenols) and caffeine (alkaloids) [1,3]. Results from several animal and epidemiological studies suggest, although not conclusively, that maternal intake of caffeine is detrimental to pregnancy outcome (in terms of foetal growth, time of delivery, abortifaciant activity or still births) [1,4–7]. In view of the fairly high caffeine content is black tea [1], a possibility exists that consumption of tea during gestation may pose hazards to the outcome of pregnancy.…”

Study of sensory-motor and somatic development of the offspring of rats (Wistar) treated with caffeine

“…Caffeine has a rapid absorption in the gastrointestinal system, and passes into blood and fetal tissues including the central nervous system, when it is administered to the mother (Matijasevich, Santos, Barros, 2005). Highest blood caffeine levels are reached between 3 and 120 minutes, during which time it is rapidly distributed throughout body tissues, achieving equilibrium between blood and tissue levels (Golding, 1995).…”