5 or more cups of coffee per day cuts IVF success chance by 50 pcPublished On: Tue, Jul 3rd, 2012 | Sexual Health | By BioNews
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 percent and the live birth rate by 40 percent.
“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.
Similarly, a Cochrane review from 2009 found there was insufficient evidence to confirm or deny the effect of “caffeine avoidance” on pregnancy outcome. However, one much cited study from 2004 showed that time-to-pregnancy was significantly extended in women when coffee or tea intake was more than six cups per day or when the male partner consumed more than 20 alcohol units per week.
This latest Danish study, which was performed in a large public IVF clinic, was a prospective follow-up of 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). The statistical analysis controlled for such confounding variables as female age, female smoking habits and alcohol consumption, cause of infertility, female body mass index, ovarian stimulation, and number of embryos retrieved.
The analysis showed that the “relative risk” of pregnancy was reduced by 50 percent in those women who reported drinking five or more cups of coffee per day at the start of treatment – and the chance of live birth was reduced by 40 percent (though this trend was not quite statistically significant). No effect was observed when the patients reported coffee consumption of less than five cups.
Commenting on his results, Dr Kesmodel proposed that in a study of greater numbers the statistical effect of coffee on IVF delivery results would have most likely been significant, and comparable to the effects seen on pregnancy rate.
“There is limited evidence about coffee in the literature,” said Dr Kesmodel, “so we would not wish to worry IVF patients unnecessarily. But it does seem reasonable, based on our results and the evidence we have about coffee consumption during pregnancy, that women should not drink more than five cups of coffee a day when having IVF.
Dr Kesmodel presented the findings at the annual meeting of ESHRE.