Coffee drinking can cut IVF success by half

[Posted: Wed 04/07/2012 by Gillian Tsoi www.irishhealth.com]

Drinking large amounts of coffee every day can reduce the chance of IVF success by around 50%, according to new research from Denmark.

Researchers there say that women who drink five or more cups of coffee a day severely reduce their chance of success from IVF treatment.

They followed almost 4000 IVF and intra-cytoplasmic sperm injection (ICSI) patients, and concluded that the adverse impact of coffee consumption was "comparable to the detrimental effect of smoking".

The research results showed that downing five or more cups of coffee a day reduced the clinical pregnancy rate by 50% and the live birth rate by 40%.

"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 Schiøler Kesmodel from the Fertility Clinic of Aarhus University Hospital in Denmark, where the study was carried out.

The Danish study was performed in a large public IVF clinic and focused on over 3950 women having IVF or ICSI as fertility treatment.

Information on the amount of coffee consumed by each patient was gathered at the beginning of treatment (and at the start of each subsequent cycle).

The study took into account factors such as female age, female smoking habits and alcohol consumption, cause of infertility, female body mass index, ovarian stimulation, and thte number of embryos retrieved.

The results showed that the "relative risk" of pregnancy was reduced by 50% in those women who reported drinking five or more cups of coffee daily at the start of treatment - and the chance of live birth was reduced by 40%.

No effect was observed when the patients reported coffee consumption of less than five cups.

"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.

"The fact that we found no harmful effects of coffee at lower levels of intake is well in line with previous studies on time-to-pregnancy and miscarriage, which also suggest that, if coffee does have a clinically relevant effect, it is likely to be upwards from a level of four-to-six cups a day."

The study was presented at the annual meeting of European Society of Human Reproduction and Embryology (ESHRE) by Kesmodel from the Fertility Clinic of Aarhus University Hospital in Denmark.