The toxicology of chemical interactions during pregnancy in the mouse: caffeine and phenytoin

Caffeine intake during pregnancy and adverse outcomes: An integrative review

Caffeine intake during pregnancy is common. Caffeine crosses the placenta, raising concerns about its possible deleterious effects on the developing embryo/fetus. Studies on this subject show conflicting results, and still there is no consensus on the recommended dose of caffeine during pregnancy. We performed an integrative review with studies from six databases, using broad MESH terms to allow the identification of publications that addressed the outcomes of caffeine use during pregnancy, with no date limit for publications, in English and Portuguese language. The research returned 16,192 articles. After removing duplicates, screening by title, abstract and full-text, we evaluated 257 and included 59 articles. We found association between caffeine intake and pregnancy loss, low birth weight, cardiac and genital anomalies, higher body mass, and neurodevelopmental and neurobehavioral outcomes. The effects were often dose dependent. No association with prematurity has been demonstrated, but one study showed a small reduction in gestational age with increasing doses of caffeine intake. Defining a safe dose for caffeine intake during pregnancy is a challenging task due to the heterogeneity in study designs and results, as well as the difficulty of reliably assessing the amount of caffeine consumed. In some studies, exposures below the recommended level of caffeine intake during pregnancy (200 mg/day), as suggested by the guidelines, were associated with pregnancy loss, low birth weight, cardiac and genital anomalies, higher body mass, and neurodevelopmental and neurobehavioral outcomes. Well-designed studies with reliable quantification of caffeine intake are needed to assess the safety of low doses during pregnancy.

Developmental effects of propyphenazone in analgesic and antipyretic combination with caffeine or paracetamol

The aim of the study was to determine the influence of an over-the-counter (OTC) mixture of propyphenazone with caffeine or paracetamol on prenatal development. Propyphenazone:caffeine and propyphenazone:paracetamol mixtures were prepared with constant 3:1 and 3:5 ratios, respectively. Three dose levels of each of the mixtures were administered separately in Tween-80 water suspension once a day to pregnant Wistar rats on gestation days 8-14. The low dose was similar to the OTC preparations, 2.1 mg/kg of propyphenazone, 0.7 mg/kg of caffeine or 3.5 mg/kg of paracetamol. The middle dose was 21.0, 7.0 or 35.0 mg/kg, and the highest 210.0, 70.0 or 350.0 mg/kg for propyphenazone, caffeine or paracetamol, respectively. On day 21 of gestation the fetuses were delivered by hysterectomy. Dead or live fetuses, resorptions and the number of implantation sites were counted. Live fetuses were examined for external, visceral and skeletal malformation. Postimplantation mortality was calculated. Dose-dependent effects in the middle and high dose groups on fetal body weight/length and placental weight were found. No increase in external or internal congenital anomalies was found in any of the mixture-exposed groups. Prenatal coadministration of propyphenazone with caffeine or paracetamol caused intrauterine growth retardation but did not increase external or internal congenital anomalies. The risk of midline defects (umbilical hernia and gastroschisis) is discussed.

Occurrence of pharmaceuticals in a water supply system and related human health risk assessment

A monitoring study of 31 pharmaceuticals along Lisbon's drinking water supply system was implemented, which comprised the analysis of 250 samples including raw water (surface water and groundwater), and drinking water. Of the 31 pharmaceutical compounds, only sixteen were quantified in the analyzed samples, with levels ranging from 0.005 to 46 ng/L in raw water samples and 0.09-46 ng/L in drinking water samples. The human health risk assessment performed showed that appreciable risks to the consumer's health arising from exposure to trace levels of pharmaceuticals in drinking water are extremely unlikely, as RQs values were all below 0.001. Also, pharmaceuticals were selected as indicators to be used as a tool to control the quality of raw water and the treatment efficiency in the drinking water treatment plants.

DNA repair during organogenesis

DNA damage caused by genotoxic agents can impact on virtually any cellular process due to its ability to affect gene expression and subsequent gene products. The importance of repairing damaged DNA is evidenced by the variety of DNA repair pathways that have evolved in all living organisms, and the human syndromes caused by a lack of this repair ability. This review focuses on the expression and activity of DNA repair pathways during mammalian organogenesis, and the role of these pathways in ensuring the stability of the conceptal genome. DNA repair capacity may play a role also in the response of the conceptus to genotoxic agents that may induce malformations; the consequences of exposure to a genotoxic agent during organogenesis depend on the extent of the damage and on the ability of the embryo to respond by repairing DNA or arresting cell division. The four main repair pathways (nucleotide excision repair, base excision repair, mismatch repair, and recombination repair) are expressed to various degrees during organogenesis, as are members of the genotoxic stress-activated cell cycle checkpoint pathways. Developmental-stage-specific alterations in transcript levels, protein levels, as well as activity, indicate that the regulation of DNA repair pathways during development is complex. The importance of DNA repair pathways in endogenous damage control is illustrated by the sensitivity of development to their disruption if some of these genes are mutated. Furthermore, the conceptus has a limited capacity to alter DNA repair responses following exposure to genotoxic agents.

Teratogen update: evaluation of the reproductive and developmental risks of caffeine

Caffeine is a methylated xanthine that acts as a mild central nervous system stimulant. It is present in many beverages, including coffee, tea, and colas, as well as chocolate. Caffeine constitutes 1-2% of roasted coffee beans, 3.5% of fresh tea leaves, and approximately 2% of mate leaves (Spiller, '84; Graham, '84a,b). Many over-the-counter medications, such as cold and allergy tablets, headache medicines, diuretics, and stimulants also contain caffeine, although they lead to relatively minimal intake (FDA, '86). In epidemiological studies, it is assumed that one cup of coffee contains < or =100 mg of caffeine, and soft drinks, such as colas, contain 10-50 mg of caffeine per 12-ounce serving. The per-capita consumption of caffeine from all sources is estimated to be about 3-7 mg/kg per day, or approximately 200 mg/day (Barone and Roberts, '96). Consumption of caffeinated beverages during pregnancy is quite common (Hill et al., '77) and is estimated to be approximately 144 mg/day, or 2.4 mg/kg for a 60-kg human (Morris and Weinstein, '81). However, pregnant women appear to consume slightly less than do other adults, approximately 1 mg/kg per day (Barone and Roberts, '96). This decrease may be interrelated with taste aversion (Hook, '76; Little, '82). The medical literature contains many varied references that appear to indicate that human adverse reproductive/developmental effects are produced by caffeine. If caffeine indeed causes such effects, the reproductive consequences could be very serious because caffeine-containing foods and beverages are consumed by most of the human populations of the world, and consumption in the United States is estimated to be 4.5-kg/person/year (Narod et al., '91). Therefore, the medical literature dealing with developmental and reproductive risks of caffeine was reviewed, and the biological plausibility of the epidemiological and animal findings, as well as the methods and conclusions of previous investigators, were evaluated. The epidemiological studies describe exposures of women to caffeine during pregnancy, as well as the occurrence of congenital malformations, fetal growth retardation, small-for-date babies, miscarriages (spontaneous abortions), behavioral effects, and maternal fertility problems that presumably resulted from the caffeine consumption. A few epidemiological studies were concerned with the genetic effects of preconception exposures to caffeine. Animal studies, conducted mostly in pregnant rats and mice, were designed to produce malformations. The objectives of the present review are to summarize the findings from the various clinical and animals studies, objectively discuss the merits and/or faults inherent in the studies and establish a global reproductive risk assessment for caffeine consumption in humans during pregnancy. It should be noted that evaluation of the developmental risks of caffeine based solely on epidemiological studies is difficult because the findings are inconsistent. Even more important, is the fact that caffeine users are subject to multiple confounding factors that make analyses difficult and prevent investigators from reaching definitive conclusions. For example, the caffeine content of foods and beverages can vary considerably, which can interfere with obtaining valid interpretations from many human studies. Isolated epidemiological studies dealing with the risk of abortion, without evaluating other developmental and reproductive effects, are the most difficult to interpret, because they present special problems that are sometimes ignored in epidemiological studies. The results of animal studies are probably most helpful in solving some of the dilemmas created by the epidemiological studies. An animal study reported in 1960 first focused our attention on the potential developmental effects of caffeine. However, the exposure reported by Nishimura and Nakai ('60) was an intraperitoneal dosage of 250 mg/kg in the mouse, an extremely high dosage that would result in a blood plasma level that could never be obtained from consuming caffeine containing products. More recent animal studies have demonstrated, that depending on the method of administration and species, the developmental NOEL in rodents is approximately 30 mg/kg per day, the teratogenic NOEL is 8,100 mg/kg per day, and the reproductive NOEL approximately 80-120 mg/kg per day. Lack of biological plausibility to support the concept that caffeine has been responsible for human malformations is another important part of this analysis. For example, no one has described the Caffeine "teratogenic syndrome," a cluster of malformations associated with caffeine ingestion. Proven human teratogens have an identifiable syndrome. The malformations described in the animal studies at very high doses fit the description of vascular disruptive types of malformations. (ABSTRACT TRUNCATED)

Potential teratogenic and neurodevelopmental consequences of coffee and caffeine exposure: a review on human and animal data

The teratogenic effect of caffeine has been clearly demonstrated in rodents. The sensitivity of different animals species is variable. Malformations have been demonstrated in mice at 50-75 mg/kg of caffeine, whereas the lowest dose usually needed to induce malformations is 80 mg/kg in rats. However, when caffeine is administered in fractioned amounts during the day, 330 mg/kg/day are necessary to reach teratogenicity in rats. In rodents, the most frequently observed malformations are those of the limbs and digits, ectrodactyly, craniofacial malformations (labial and palatal clefts) and delays in ossification of limbs, jaw and sternum. Nevertheless, even in rodents, caffeine can be considered as a weak teratogenic agent, given the quite large quantities of caffeine necessary to induce malformations and the small number of animals affected. In humans, caffeine does not present any teratogenic risk. The increased risk of the most common congenital malformations entailed by moderate consumption of caffeine is very slight. However, caffeine potentiates the teratogenic effect of other substances, such as tobacco, alcohol, and acts synergistically with ergotamine and propranolol to induce materno-fetal vasoconstrictions leading to malformations induced by ischemia. Therefore, even though caffeine does not seem to be harmful to the human fetus when intake is moderate and spread out over the day, some associations, especially with alcohol, tobacco, and vasoconstrictive or anti-migraine medications should be avoided. Maternal consumption of caffeine affects brain composition, especially in case of a low-protein diet and also seems to interfere with zinc fixation in brain. Maternal exposure to caffeine induces also long-term consequences on sleep, locomotion, learning abilities, emotivity, and anxiety in rat offspring, whereas in humans, more studies are needed to ascertain long-term behavioral effects of caffeine ingestion by pregnant mothers.

Activity profiles of developmental toxicity: design considerations and pilot implementation

The available literature was searched for quantitative test results from both in vitro and in vivo assays for developmental toxicity for five model compounds: cyclophosphamide, methotrexate, hydroxyurea, caffeine, and ethylenethiourea. These compounds were chosen on the basis of their extensive utilization in a variety of assay systems for developmental toxicity as evidenced by their representation in the ETIC database (each generally has 100-500 citations encompassing multiple test systems). Nine cellular-based assays, six assays using whole embryos in culture, as well as Segment II and abbreviated exposure tests for mammalian test species are included in the database. For each assay, the critical endpoints were identified, each of which was then provided a three-letter code, and the criteria for extraction of quantitative information were established. The extracted information was placed into a computerized reference file and subsequently plotted such that the qualitative (positive/negative) and quantitative (e.g., IC50, highest ineffective dose (HID), lowest effective dose (LED] results across all test systems could be displayed. The information contained in these profiles can be used to compare qualitative and quantitative results across multiple assay systems, to identify data gaps in the literature, to evaluate the concordance of the assays, to calculate relative potencies, and to examine structure-activity relationships.

Effects of combinations of maternal agents on the fetal cerebrum in rat--ethanol or caffeine with X-irradiation in utero

Fetal cerebral development influenced by maternal ethanol or caffeine either singly or in combination with X-irradiation was investigated in rat. Female Wistar rats were given 20% ethanol, 0.04% caffeine and water during the premating period and pregnancy, and 0.03% vitamin E only during pregnancy. Pregnant rats were X-irradiated with 100R or sham-irradiated on gestational day 13. Ethanol-treatment alone much reduced the fetal body and cerebral weights, and X-irradiation alone resulted in great reductions in weight and DNA concentration in the fetal cerebrum. The reduction in body weight with ethanol exceeded that with X-irradiation, therefore, the addition of X-irradiation had no effect on that of ethanol. The reduction in cerebral weight on X-irradiation exceeded that with ethanol, thus the addition of ethanol had only a slight effect on that with X-irradiation. The decrease in body and cerebral weights and the increase in lipid peroxide (LP) formation on caffeine-treatment and the decrease in cerebral weight and the increase in LP on vitamin E-treatment were inhibited by X-irradiation as compared to the combined effects of the other drink treatments. The increase in placental weight and the decrease in cerebral weight on ethanol-treatment and the decrease in placental, body and cerebral weights on caffeine-treatment, which findings were covered by the addition of X-irradiation, became much clearer on single drink treatment. Independently of X-irradiation, ethanol-treatment resulted in increased fetal mortality and LP, and decreased body weight. These results suggest that the combined effects of maternal agents on live fetuses should be investigated as to whether they act independently of or dependently with each other and how the effects appear either singly or mixed.