Researchers at the Center for Human Reproduction in New York began exploring the effects of DHEA in 2004, when they learned that an older patient of theirs had been taking the drug without telling them. Desperate to conceive a child using her own eggs, the then 42-year-old woman had scoured the scientific literature and found a very small trial suggesting that DHEA could improve ovarian function (Human Reproduction, vol 15, p 2129).
The number of eggs doctors could extract from her jumped from one per cycle of IVF to 19 over the course of seven cycles. "We were kind of stunned," says Norbert Gleicher, the doctor who treated her. Since then, Gleicher has been advising some of his patients aged 40 and above to take three dose of DHEA every day. Each 25-milligram dose costs under $1.
At a meeting of the American Society for Reproductive Medicine in Washington DC last week, Gleicher's colleague David Barad presented data from a pilot study involving 27 women, eight of whom had received DHEA. Women taking the drug produced more eggs and had twice as many high-quality embryos suitable for transfer into the uterus per cycle. The use of DHEA appears to have helped boost the pregnancy rate from 11 per cent to 23 per cent among patients aged 40 and above in Gleicher's clinic. Other clinics are beginning to focus research efforts on DHEA, too.
It is a hormone produced naturally by the body, where it is converted into the sex hormones oestrogen and testosterone. Exactly how it influences egg maturation is unclear. According to Barad, it appears to induce a form of polycystic ovary syndrome (PCOS), a condition in which high levels of the hormone cause a "backlog" of ripening eggs that fail to release naturally. Women taking DHEA as part of IVF treatment avoid the negative symptoms linked to PCOS, such as weight gain, perhaps because doctors harvest the ripe eggs each month, Barad says.
Janet Hall, a reproductive endocrinologist at the Massachusetts General Hospital in Boston, believes the studies so far suggest DHEA warrants further investigation. "It's very tantalising data," she says, but stresses that large, placebo-controlled studies are needed to assess the true impact of the drug.
Gleicher is worried that women may take DHEA without consulting their doctors: "We urge women not to do it on their own." 
