The aim of this article is to describe unexpected spontaneous pregnancies in poor responder patients with long-term infertility, when treated with dehydroepiandrosterone (DHEA) supplementation prior to in vitro fertilization (IVF). Our evaluation was carried out in two groups of women. The first group included 39 young women with <40 years, all treated with DHEA because of a previous poor response. The second group included 38 women over 40 years who received DHEA supplementation. Controls for latter group were 24 comparable women who had not been treated with DHEA before the first IVF cycle to evaluate the spontaneous pregnancy rate during preparation to IVF. Three tablets daily of 25 mg micronized DHEA were administered for at least 12 weeks before starting a long stimulation protocol for IVF. Surprisingly, spontaneous pregnancy rate significantly increased after DHEA treatment, allowing to achieve 10 spontaneous pregnancies and 9 spontaneous ongoing pregnancies among young poor responders. Pregnancy rate and ongoing pregnancy rate obtained before starting the IVF cycle were also significantly higher in older women treated with DHEA than in the control group: 21.05% and 13.15% and 4.1% and 0, respectively. Our results show that DHEA supplementation improves the ovarian function in poor responders and in women over 40 years, suggesting that this molecule alone can raise fecundity and fertility treatment success in women with poor prognosis for pregnancy.