Coffee during pregnancy
OK. The coffee story: Overall it is agreed that moderate consumption of coffee is safe in pregnancy. So what is moderate and what can I drink you ask???
Caffeine is present in many beverage and food products, most commonly associated with coffee. There has often been a suggestion that caffeine is unhealthy in pregnancy. Caffeine does cross the placenta and is slowly metabolised by the fetus. In fact the fetus metabolises caffeine more slowly than adults and thus has a more prolonged exposure. Theoretically, caffeine can cause the release of a substance that closes blood vessels (‘vasoconstriction’) and therefore may be associated with reduced placental blood flow to the fetus. Also, some animal studies have suggested a link to birth defects in rats. This has not been seen in humans, although there are sources that say there is or may be a link.
The problem with studies in humans is there are many factors that make the study of caffeine intake difficult. Thus the data is inconclusive as many of the studies have inherent flaws. These flaws include: the link between drinking coffee and smoking (I know, I know – my patients don’t smoke – but studies of less well behaved people than my patients have difficulty separating the two habits and we KNOW smoking is bad for babies!); genetic variances between people (some people metabolise caffeine faster than others, therefore some fetuses metabolise the caffeine faster than others); the broad variation in actual caffeine content of various coffees and foods; the fact that most studies rely on patients to self-report their food and beverage (ie the pregnant person in the study tries to remember their caffeine intake – and we know how good a pregnant woman’s memory is!!); the blood concentration of caffeine is usually not accurately measured.
So taking all these factors into account it is very difficult to demonstrate with scientific certainty what caffeine does to the developing fetus. However, it is agreed between many learned organisations across Australia, the UK, Canada and the USA (amongst many other countries), that low to moderate caffeine consumption is NOT associated with birth defects. There is possibly a slight drop in birthweight of those babies born to mothers with moderate caffeine consumption but this appears to be an insignificant amount (about 50 to 70g).
There does NOT appear to be a link to miscarriage at moderate levels of caffeine consumption.
There does NOT appear to be any long-term harm from caffeine consumption.
There does NOT appear to be a link to premature birth.
So what is recommended as acceptable caffeine consumption? Most organisations agree that 200-300mg of caffeine daily is safe. What does this mean? Well an instant coffee is ABOUT 100mg (but who would want to drink that anyway?). Even decaf has some caffeine (about 5mg and ditto). A brewed or plunger style coffee is about 150-200mg and an expresso is about 200-300mg. Chocolate has about 5-10mg (a cup of chocolate). Tea has up to 50mg, green tea about 30mg. Soft drinks contain about 50mg per can but energy drinks are higher.
What do I think? Well I was caffeine free for my first baby (the peak of my good behaviour, just like most pregnant women with their first baby), my second I fell off the wagon – mugs and mugs of coffee daily (but he is a naughty little teenage liar now at the age of 13 – ???? – make your own associations!) and nos 3 and 4 I was BALANCED with a moderate approach (they are not liars). So I think it should be most wisely avoided in first trimester but a weak coffee is fine and for the desperate I think 1 expresso a day (or equivalent) is perfectly acceptable. For second and third trimesters I think 2 expressos daily is acceptable (a morning kick start and an afternoon booster) but if there are any other factors that may be affecting placental function probably best to avoid caffeine or just have a weak coffee.
Ironically, the studies suggest that moderate caffeine intake prior to conception seems to PROTECT against diabetes of pregnancy and caffeine intake during pregnancy PROTECTS again pre-eclampsia but…. I am skeptical so don’t use it as a justification for caffeine frenzy…..that can wait until AFTER the birth…along with the soft cheese and sushi frenzy…..