Researchers have suggested that a life-threatening complication of fertility treatment could be prevented by a cup of coffee, after a study identified a possible cause.
In vitro fertilisation has resulted in the birth of many babies since the first "test tube" baby in 1978.
But around 5% to 10% of women undergoing IVF experience a condition known as ovarian hyperstimulation syndrome (OHSS).
Although the majority of cases are mild, with symptoms including abdominal bloating, nausea and weight gain, in its most serious form it can cause blood clotting disorders, kidney damage and chest pain.
Scientists from Middlesex University and Barts and The London School of Medicine and Dentistry who analysed fluid around the human egg reported finding surprisingly high levels of the chemical adenosine. They believe OHSS is caused when IVF drug stimulation creates high levels of adenosine, causing the blood vessels to dilate and blood fluid to leak into tissue.
The authors of the study, published in Metabolism Journal, wrote: "Although adenosine has been detected in follicular fluid before, we were surprised at the extremely high levels detected in this study."
They described the chemical as a "significant contender as the molecular cause of OHSS".
To detect adenosine in blood samples, the scientists used a technique called metabolomics, which involves the study of chemical evidence of cellular processes. The researchers said a solution could lie in caffeine, which acts as a block to adenosine.
Ray Iles, professor of biomedical science at Middlesex University, said: "It may be that a cup of strong coffee with every IVF cycle could reduce the chances of OHSS. Caffeine competes with adenosine for the same receptors, effectively blocking adenosine's action, and it could therefore potentially treat the cause of this condition."
Further research is under way at Barts and The London Centre for Reproductive Medicine with IVF patients who have suffered OHSS to find out if caffeine could help avoid the complication.