- Foetal caffeine exposure
- Recommendations for caffeine consumption during pregnancy
- Health effects of excessive caffeine consumption during pregnancy
- Reducing caffeine consumption
Caffeine is a naturally occurring substance which stimulates the central nervous system and can temporarily relieve tiredness and increase alertness. While humans have no nutritional requirement for caffeine (caffeine is not an essential part of the human diet), most adults can safely consume moderate amounts of caffeine. Pregnant women can also safely consume caffeine, however they should consume less caffeine than non-pregnant women, to protect the health of their developing foetus.
Caffeine is passed onto the foetus via the placenta (the membrane that nourishes the foetus during pregnancy). A foetus is therefore exposed to caffeine when it is consumed by a pregnant woman. However, cytochrome P450 1A2, which breaks down caffeine in children and adults, is absent in the foetus. As a result, a foetus cannot metabolise caffeine, and caffeine entering the foetus’s system is not cleared out.
It is recommended that pregnant women restrict their caffeine intake to 200 mg per day to reduce the risk of adverse affects to the pregnancy and the foetus. A doctor or other health professional can provide advice about reducing caffeine intake if you have difficulty.
Consuming excessive caffeine during pregnancy is associated with a range of adverse health outcomes for the woman and her foetus.
Excessive caffeine consumption (> 300 mg per day) during pregnancy has been associated with bearing a low birth weight infant (an infant which weighs less than 2.5 kg at birth) and miscarriage. However, not all studies have shown a relationship between caffeine intake and pregnancy outcomes. This may be because studies have relied on women’s reports of how much coffee and tea they drink to measure caffeine intake. This may not be a reliable measure, as women may not remember exactly how much coffee and tea they drink, or they may also consume caffeine in other products, such as chocolate and medication which they do not report to researchers.
A study involving over 7,000 Dutch women found that high caffeine consumption was associated with bearing a small for gestational age child (a child which is smaller than expected for the length of the pregnancy, taking into consideration that a baby born premature is smaller than a baby born at full term) and impaired foetal growth. Another study of British women reported an increased risk of foetal growth restriction with caffeine intake ≥ 100 mg per day, which is less than the recommended safe levels. Women with daily caffeine consumption of 100–199 mg had a 1.2 times increased risk of foetal growth restriction while those who consumed 200–299 mg had a 1.5 times increased risk of foetal growth restriction.
The link between caffeine intake and miscarriage were examined in a recent Swedish study. Non-smoking women who consumed more than 300 mg of caffeine per day were more likely to experience a miscarriage between 6–12 weeks gestation than those who consumed less caffeine. The risk of miscarriage increased relative to the amount of caffeine consumed. Non-smoking women consuming 300–499 mg were 1.4 times more likely to miscarry and those consuming ≥ 500 mg were 2.2 times more likely to miscarry.
A New Zealand study reported that the babies of women who consumed greater than 400 mg of caffeine per day during pregnancy were 1.65 times more likely to die of sudden infant death syndrome than the babies of women who consumed less caffeine.
More information on SIDS.
The New Zealand study also found that infants born to women who consumed high quantities of caffeine whilst pregnant were more likely to experience sleep apnoea (difficulty breathing during sleep).
Pregnant women who consume more than 200mg of caffeine daily (about two cups of brewed coffee) should reduce their caffeine consumption whilst pregnant. Health professionals advise individuals to reduce their caffeine consumption gradually, for example by replacing one caffeinated drink with a non-caffeinated alternative each day, in order to avoid withdrawal symptoms.
|For more information on caffeine, including consumption by adults, children and pregnant women, as well as some useful tools, see Caffeine.|
|For more information about pregnancy, including preconception advice, stages of pregnancy, investigations, complications, living with pregnancy and birth, see Pregnancy.|
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