Coffee & Caffeine During Pregnancy
Links to Learning Disabilities, ADD and Behavior Disorders
INTRODUCTION
A very large review of the coffee/caffeine research was presented by French researcher, Dr. Astrid Nehlig, in the 1994 journal Neurotoxicology and Teratology. His review summarized over 200 medical journal articles on the coffee/caffeine subject. Below are what we consider to be the most significant quotes from Dr. Nehlig’s article:
"The teratogenic effect of caffeine has been clearly demonstrated in rodents. However, rodents are much more sensitive than primates to the teratogenic effects of many substances. Moreover, the quantity of caffeine needed to induce malformations in rodents reaches doses that are toxic in man. Thus a woman weighing 60 kg would have to consume 50-70 cups of coffee per day (or at least 20 cups if interspecific metabolic variations are taken into account) to absorb the equivalent of 80-100 mg/kg/day of caffeine, which is the dose usually required for development of malformations rats."
"World coffee consumption is increasing. Analyzing the data from surveys carried out in the United States, Japan, and West Germany for the period of 1980-1991, it appears that the number of coffee drinkers has decreased by 2-5% in three countries, while coffee consumption, in terms of number of cups/consumer/day has increased in each country."
"A mean size cup (150 ml) of caffeinated coffee contains in general about 90 mg of caffeine and 63 mg of caffeine for soluble instant coffee. The same volume of decaffeinated coffee contains 3 mg of caffeine, whereas the content of caffeine reaches 32-42 mg in 150 ml of tea and 16 mg in 150 ml of cola drinks."
"The daily consumption of caffeine in the general population ranges from 202-283 mg of caffeine which represents 2.7-4.0 mg/kg/day in males and females 20-75 years old."
"The half life of caffeine ranges from .7 -1.2 hours in the rat and mouse, 3-5 hours in the monkey and 2.5-6 hours in humans."
"Caffeine half-life is increased in the neonatal period in both animals and humans due to the immaturity of hepatic (liver) enzyme systems, namely cytochrome P-450. Half lives of 40-130 hours are found in premature and newborn infants. They decrease rapidly to 14.4 and 2.6 hours in 3-5 month and 5-6 month infants, respectively. Longer half-lives of caffeine are found in breast-fed than in formula fed infants."
"The U.S. Food and Drug Administration published a warning in 1980 advising pregnant women to restrict or even eliminate consumption of coffee given the teratogenic effect (the ability to cause birth defects) observed in rodents."
"Finally, in comparing results of drug administration in both humans and animals, a correction factor for the dose must be applied, also called metabolic body weight. Indeed, dose equivalents based on metabolic body weight are substantially lower than those based on body weight: 20 mg/kg in the rat is equivalent to about 17 cups of coffee (at 100 mg/cup) in a 70-kg man on a body weight basis, but only 4 - 6 cups when corrections are made for differences in metabolic body weight."
"In the monkey, spontaneous abortions and stillbirths have been recorded at the 2 doses used, 10-15 and 25-35 mg/kg/day of caffeine. (Equivalent to 2-3 cups and 5-8 cups of coffee, respectively). In humans, coffee and caffeine consumption from other sources have been associated with a higher incidence of spontaneous abortions (in 5 studies."
"The association between coffee and/or caffeine intake and prematurity seems then to be very weak, or absent. According to one study, 11% of the spontaneous abortions can be attributed to smoking, 5% to alcohol, and only 2% to coffee."
"The risk for any kind of congenital abnormalities is 3.7% in individuals who consume caffeine and 1.7% in those who do not. The difference is statistically significant."
"It has also been shown that absorption of caffeine has a vasoconstrictive effect on placental circulation. Blood flow is not modified in the umbilical fetal vein but intervillious placental blood flow is significantly diminished after absorption of 2 cups of coffee. This decrease in blood flow along with increased concentration of noradrenaline induced by caffeine in the maternal serum could represent a potential risk for the fetus."
"Caffeine diffuses through the placenta and accumulates in the brain of the fetus (3 studies) Caffeine concentration of the fetal rat is higher in the brain than in the placenta whereas the metabolites of methylxanthine are evenly distributed between brain and placenta."
"Exposure of female rats to caffeine during pregnancy (.04% in drinking water) causes proportionally greater loss in brain weight than in body weight (3 studies)."
"When pregnant rats ingest 10-20 mg/kg day caffeine, the cerebral concentrations of these various elements are lower in offspring at birth."
"Exposure to caffeine during gestation and lactation (.04% in drinking water) also induces modifications in cerebral concentrations of catecholamines, tyrosine, tryptophan, serotonin, 5-hydroxyindole acetic aid, and cyclic nucleotides in the brain of 1 - 35 day old rat (4 studies), which can cause behavioral abnormalities, such as hypoactivity, during development of the animal."
"...Thus, it seems that early caffeine exposure, even at quite low doses, is able to induce a wide variety of neurochemical changes. These deficits concern both constitutive material such as proteins, DNA and RNA, and functional material such as neurotransmitters and ions."
"Offspring of female rats exposed to 60 or 100 mg/kg caffeine in their drinking water throughout gestation have reduced learning capacities as adults in a novel environment. In an open field, these animals also spend less time grooming, playing, and touching new objects. The authors concluded that the behavioral effects induced by prenatal caffeine exposure could be related to the "hyperactive" children syndrome (Sinton, C. M. et. al., 1981)."
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Smaller Head Circumference –
Lower Birth Weight After 300 mg Caffeine Intake
Source: Neurobehavioral Toxicology and Teratology, Vol. 7:9-17, 1985
Although 300 mg of caffeine intake represents approximately 2 or 3 cups of coffee, many people don’t realize the amount of caffeine they can consume from other sources besides coffee. Most studies, such as the ones previously mentioned, look for toxic effects based on the number of cups of coffee consumed per day. However, if significant amounts of caffeine can be ingested from other sources besides coffee, this could hide the true dangers when comparing coffee drinkers with non-coffee drinkers.
In this 1983 Ottawa study at Carleton University, Canada, the researchers analyzed the total caffeine intake from all sources in 286 pregnant women. For the first trimester of their pregnancy, coffee accounted for only 56% of their total caffeine intake, tea accounted for 37% of caffeine intake, while caffeinated soft drinks, chocolate bars, chocolate drinks and caffeinated medications accounted for approximately 7% of caffeine intake. These levels maintained about the same throughout pregnancy.
Approximately 4% of the women during pregnancy consumed 100 - 300 mg of coffee daily while 4% of the group consumed over 300 mg of coffee daily.
The researchers stated,
"The most marked effect associated with heavy caffeine use (over 300 mg daily) in the present study were the reduced birth weight and the smaller head circumference that persisted after statistically controlling for other potentially contributing factors."
The mean head circumference of the infants born to the heavier caffeine users was 1.1 centimeters (cm) smaller when compared to those consuming under 300 mg of caffeine daily (33.5 cm compared with 34.6 cm, respectively). This difference was considered significant. A significant decrease of 379 grams in average birth weight was also observed in the heavier caffeine group. The average weight of infants born to the heavier caffeine users was less than women consuming little caffeine (3537 grams for the low caffeine users and 3158 for the heavy caffeine user- nearly a 400 gram difference).
In summary, the researchers stated,
"It is during the last trimester of pregnancy that the greatest spurt in fetal growth occurs. The present results suggest that daily caffeine intake of 300 mg or more can interfere with normal fetal growth... The observed, relatively small birth weight reductions may be of minor importance to a healthy full-term baby of acceptable weight but may be of major clinical significance for a preterm or small infant."
Drs. B. Watkinson and P. A. Fried
Carleton University, Ottawa, Ontario, Canada
Maternal Caffeine Use Before, During and After Pregnancy and Effects Upon Offspring
Neurobehavioral Toxicology and Teratology, Vol. 7:9-17, 1985
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Caffeine Exposure Increases Learning Problems and Hyperactivity
in Laboratory Mice
Abstract: Dams from two strains of mice, were treated during gestation with caffeine, at doses of about 60, 80, and 100 mg/kg/day, in their drinking water. The resulting offspring were behaviorally tested over a 6 month period commencing at age 9 months. When compared with controls, mice from dams that had received caffeine demonstrated longer latencies in passive avoidance test, and differences were also noted for female offspring in activity and habituation measures. Having controlled as far as possible for post natal maternal and environmental effects, the most likely conclusion is that caffeine has a direct pharmacological action on the fetus, and should therefore be classed as a behavioral teratogen in mice.
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