PREGNANT women drinking three cups of coffee a day or more can substantially increase the chance of losing their baby or retarding growth of the foetus, according to research published yesterday.
The risk is progressive so the more caffeine pregnant women, take the greater the effect, the researchers write in the Journal of the American Medical Association.
In fact women who drank more than 321mg of caffeine a day increased their risk of spontaneous abortion by nearly three times. The journal explains that one standard cup (8oz) of coffee is equivalent to 100mg of caffeine.
Dr Claire Infante-Rivard from the Department of Community Health, University of Montreal, said that a woman drinking one cup of coffee a day, or 48-162mg of caffeine, increases her risk by 29 per cent. But a woman taking 163-321mg caffeine a day in coffee or cola drinks nearly doubles the risk. Higher levels of coffee drinking before pregnancy also increased the risk but by a lesser degree.
Dr Infante-Rivard questioned 331 pregnant women who were admitted to hospital because of spontaneous abortion between May 1987 and November 1989 and compared them with 993 matched controls, that is women who had normal pregnancies during the same period.
The researchers took into account all the factors that are known to increase the risk of losing a pregnancy including each woman's age, her race, education, smoking an alcolhol use, her exposure through her work to chemicals and existing medical conditions.
Then the women were asked about their tea, coffee and cola drinking habits, before and during the pregnancy.
'Caffeine intake before and during pregnancy was associated with increased risk of foetal loss, supporting the US Food and Drug Administration recommendation to pregnant women, largely based on animal studies, to reduce their caffeine intake,' she says.
A spokesman for the Department of Health said their advice leaflet for pregnant women gives no specific warning on caffeine consumption during pregnancy. 'We will study this research paper with interest,' he said.
A separate paper in the Archives of Family Medicine from the American Medical Association says that warning labels on bottles of alcohol are not an effective way of warning women of childbearing age of the dangers of drinking when pregnant.
Only a quarter of American women were able to remember details of warnings about alcohol and pregnancy from bottle labels and less than 10 per cent could recall reading any warning now displayed at the point of sale in the US.