What did the media say?
The media reported that drinking more than two cups of coffee a day may double the risk of miscarriage for expectant mothers.
What did the research show?
The observational study involved 1,063 women who became pregnant during a two year period. Researchers interviewed the women on their caffeine beverage intake at around 71 days after their pregnancy had been confirmed.
A quarter, 264, of the subjects reported no consumption of any caffeine-containing beverages during pregnancy, while 635 reported consuming up to 200mg of caffeine per day and 164 drank 200mg or more – equivalent to two or more cups of coffee or five cans of cola per day.
Overall 172 women miscarried. Of these, 33 subjects were non-caffeine drinkers, 97 drank less than 200mg per day and 42 drank 200mg or more. The authors calculated that those who drank more than 200mg per day were more than twice as likely to miscarry as those who drank none.
It is the first study on the issue to fully adjust for the presence of morning sickness which often causes women to reduce their caffeine intake.
What did the researchers say?
Lead study author Dr De-Kun Li, an investigator with the health insurance company Kaiser Permanente in California, said: ‘The main message for pregnant women from these findings is that they probably should consider stopping caffeine consumption during pregnancy because this research provides clearer and stronger evidence that high doses of caffeine intake during pregnancy can increase the risk of miscarriage.’
What does this mean for nursing practice?
Although it is only an observational study, the number of subjects is large and the findings are significant. It also adds extra detail about a potential link that has already been suggested by previous research.
Dr Pat O’Brian, a spokesman for the Royal College of Obstetricians and Gynaecology, said: ‘This is the best evidence we now have on the subject and I will advise patients to avoid caffeine completely, at least for the first 12 weeks of pregnancy.’
American Journal of Obstetrics & Gynecology (2008) www.ajog.org