DENMARK - Women who drink five or more cups of coffee a day severely reduce their chance of success from IVF treatment, according to Danish researchers.
The investigators described the adverse impact as "comparable to the detrimental effect of smoking".
Results showed that the consumption of five or more cups of coffee a day reduced the clinical pregnancy rate by 50 per cent and the live birth rate by 40 per cent.
"Although we were not surprised that coffee consumption appears to affect pregnancy rates in IVF, we were surprised at the magnitude of the effect," said Dr Ulrik Schioler Kesmodel from the Fertility Clinic of Aarhus University Hospital in Denmark.
The link between caffeine and fertility has been studied on occasions in the past, with conflicting results. Some studies have found an increased incidence of spontaneous abortion in coffee drinkers, but other studies have not.
This latest Danish study, which was performed in a large public IVF clinic, followed 3959 women having IVF or ICSI as fertility treatment. Information on coffee consumption was gathered at the beginning of treatment and at the start of each subsequent cycle.