Sunday March 3, 2013
Myths and facts about caffeine intake during pregnancy
By Dr NOR ASHIKIN MOKHTAR
THE ongoing debate about whether coffee can be consumed during pregnancy continues. For a long time, coffee, tea and other caffeinated drinks have been feared by pregnant women as being harmful to their unborn babies.
The scientific evidence on the safety of caffeine consumption has varied, although the most recent authoritative statement from the American College of Obstetricians and Gynecologists recommends that caffeine intake during pregnancy should not exceed two cups of coffee per day.
Similarly, I advise my patients to avoid caffeine beverages, if they can, or to limit their intake to the recommended amount. Most women tend to err on the side of caution, by avoiding caffeine altogether.
In this column, I will look at the available evidence so far and help readers make an informed decision that best suits their lifestyle.
Careful with caffeine
We have a love-hate relationship with coffee and other caffeinated drinks, such as tea, chocolate and soda. Many of us rely on the stimulant to provide a wake-me-up, whether first thing in the morning or late in a drowsy afternoon.
Taken within reasonable limits, caffeine can improve mental alertness, by stimulating the central nervous system, heart, muscles and the centres that control blood pressure. Caffeine also has a diuretic effect, in that it increases urine flow.
While some studies have suggested that the antioxidants in caffeine have healthful properties, most conventional wisdom also says that we should moderate our daily caffeine consumption.
Obviously, too much stimulation to our system can be unhealthy, as those of us who have had six cups of coffee a day can testify to.
During pregnancy, consumption of caffeine should be even more strictly regulated, as caffeine has a different impact on the baby in the womb. For instance, caffeine consumption is strongly correlated with smoking, which is known to increase the risk of premature birth and low birth weight.
The current recommendation by the World Health Organization (WHO) is that pregnant women should not take more than 300mg of caffeine per day. Some countries, like the US, have set their own limits of 200mg, which is roughly equivalent to less than a single cup of coffee from a cafe.
Caffeine and low birth weight
There is good reason to constantly evaluate the recommendation for caffeine consumption among pregnant women, as research is always discovering new links between caffeine and pregnancy outcomes.
Currently, some new evidence points to a higher risk of low birth weight among pregnant women who consume caffeine during pregnancy.
In a study published in BMC Medicine in February, the Norwegian Institute of Public Health tracked data from 60,000 pregnancies collected over 10 years. They looked at information about motherís diet and birth details, particularly their intake of all sources of caffeine, including coffee, tea, sodas and food with cocoa (such as is found in desserts and chocolate),
The researchers found that caffeine was not associated with premature birth, but there appeared to be a link with low birth weight. They found that if the baby was expected to weigh 3.6kg at birth (average weight), every 100mg of caffeine consumed by the mother per day reduced the newbornís weight by 21-28g. Low birth weight babies are at higher risk of short- and long-term health problems.
Different sources of caffeine also had varying effects on the pregnancy and the newborn. For instance, caffeine from all sources increased the duration of the pregnancy by five hours for every 100mg consumed by the mother per day.
However, caffeine from coffee further increased pregnancy duration to eight hours for every 100mg consumed.
This suggests that it is not just caffeine itself that causes this effect, but another substance in coffee that exaggerates it.
Too young for caffeine
The mechanism of how caffeine affects the unborn baby is still unclear, although it is no surprise that whatever a mother eats or drinks, it will pass through the placenta to her baby in the womb.
While a small amount of caffeine may not have any effect on us, it is different for the unborn baby. The babyís metabolism is still maturing and cannot fully digest the caffeine that passes into its system.
Furthermore, as caffeine is a stimulant, it is bound to cause the baby to be more active than usual. Pregnant mothers will notice that their babies move around more after they have had caffeine, causing them some discomfort.
Many women also fear that drinking coffee will cause them to suffer a miscarriage. The jury is still out on this, as there is no conclusive evidence in either direction. One study in 2008 published in the American Journal of Obstetrics and Gynecology found that women who consume 200mg or more of caffeine daily were twice as likely to suffer a miscarriage, compared to women who did not consume any caffeine.
However, in the same year, another study published in the Epidemiology journal showed that women who drank between 200 and 350mg of coffee per day had no increased risk of miscarriage.
Animal studies have also suggested that caffeine can cause birth defects, premature birth, infertility and other reproductive problems. Whether these effects similarly translate to humans is less certain.
Ultimately, women have to make the decision for themselves. If abstinence is not possible, then moderation is key. Women also have to be aware that they could consume caffeine not only from coffee, but also from tea, cola and other soda drinks (including energy drinks), chocolate and even some over-the-counter medications, such as painkillers.
Datuk Dr Nor Ashikin Mokhtar is a consultant obstetrician & gynaecologist (FRCOG, UK). For further information, visit www.primanora.com. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the readerís own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.