OHSS affects between five to 10 percent of women undergoing IVF treatment and can cause bloating, diarrhoea and nausea, or lead to more severe problems such as blood clots, kidney damage and respiratory failure.
The scientists from Middlesex University in association with Bart's Hospital in London analysed fluid surrounding human eggs and found that levels of adenosine, a common molecule in the body, were high in some people.
The lead researcher on the study, Professor Ray Iles from Middlesex University, said: 'Although adenosine has been detected in follicular fluid before, we were surprised at the extremely high levels detected in this study'.
The molecule is known to cause blood vessels to become leaky, allowing fluid to escape into the tissues. Experts believe that the drugs used in IVF treatment increase the levels of adenosine, and that the ensuing leakage may be the cause of OHSS.
Other studies have shown that people metabolise adenosine at different rates, and that this is strongly linked to genetic makeup, which may explain why only some women undergoing IVF treatment have OHSS.
Individuals who clear adenosine more slowly are therefore likely to have higher levels, and to also experience more severe symptoms.
If scientists can find a way to block adenosine they may be able to reduce the effects of the condition. Fortunately, a candidate already exists in the form of caffeine.
'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', said Professor Iles.
Studies are now being carried out to see whether caffeine is able to reduce the effects of OHSS. This research is published in the journal Metabolism.