Too much caffeine in pregnancy 'can cause childhood obesity'

Norwegian report finds children at higher risk of weight gain if mothers consume caffeine

The HSE advises that women do not consume more than 200mg of caffeine a day during pregnancy. Photograph: Katie Collins/PA Wire
The HSE advises that women do not consume more than 200mg of caffeine a day during pregnancy. Photograph: Katie Collins/PA Wire

Mothers who consume moderate to high levels of caffeine during pregnancy are putting their child at risk of gaining excess weight in their early years of life, new research has found.

A Norwegian study published in the online BMJ Open journal found that a foetus exposed to “any caffeine level” while in the womb was more likely to become overweight in the first three or five years of her/his life.

The research, which was carried out among 51,000 mothers and their infants between 2002 and 2008, reveals that caffeine consumed not only from coffee and tea, but also through soft drinks or energy drinks, chocolate, sandwich spreads, desserts, cakes and sweets, can negatively impact on a young child’s weight gain. During pregnancy, it takes the body longer to get rid of caffeine which rapidly passes through tissues including the placenta.

At 22 weeks, the women surveyed were asked to record their food and drink intake. Just under half of the mothers were classified as consuming a low level of caffeine, 44 per cent consumed an average level, seven per cent a high level and three per cent a very high level. Following birth, their child’s weight, height and body length were measured 11 times over eight years.

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Further research

The study found the women who consumed a higher level of caffeine were more likely to be over 30, already have one child, consume more daily calories and smoke during pregnancy. Women with a “very high caffeine intake” during their pregnancy were more likely to be poorly educated and obese before they became pregnant, it added.

While any exposure to caffeine during pregnancy was found to impact negatively on the child’s health, mothers who consumed “average, high and very high” levels of caffeine were more likely to see their child gain excess weight.

Women are generally advised to reduce their caffeine intake during pregnancy. However, researchers from this study note that a “complete avoidance” of caffeine may be advisable based on their findings. They note that further research is needed to examine the effects of prenatal caffeine exposure on a child’s postnatal growth.

In its nutritional advice for pregnant women, the HSE advises that women do not consume more than 200mg of caffeine a day (the equivalent of two mugs of instant coffee) as high levels can result in babies having “a low birth weight, which can increase the risk of health problems in later life”. It also warns that too much caffeine can cause miscarriage.

Sorcha Pollak

Sorcha Pollak

Sorcha Pollak is an Irish Times reporter specialising in immigration issues and cohost of the In the News podcast