The authors investigated the influence of vitamin C supplementation on the therapeutic results in infertility as part of a programme of assisted reproduction in a group of 76 women (38 smokers and 38 non-smokers). Half the women (19 smokers and 19 non-smokers included in the trial) were given during the period of hormonal stimulation a daily dose of 500mg vitamin C in pellets which released it gradually in the course of 8 to 12 hours. The same number of women was in the control group. The ascorbic acid levels were in all women assessed in two urine samples (before supplementation and after collection of the follicles) and in the follicular fluid by the colorimetric method. The ovarian response to hormonal stimulation with gonadotropins (hMG, FSH) in amounts of 150-225 i.u./day combined with GnRH analogues in a short (busereline)or long protocol (triptoreline) and 5000 to 10000 i.u. human chorionic gonadotropin was evaluated by the number of formed follicles and the number of obtained oocytes. Fertilization was evaluated by the number of successfully fertilized oocytes (fertilization ratio) and the number of developed embrya. The success of comprehensive infertility treatment was evaluated by the number of achieved pregnancies. In the biological material (follicular fluid, urine) of women in the supplemented group the ascorbic acid levels were significantly elevated. Vitamin C administration during the period of hormonal stimulation was manifested by a higher number of pregnancies (34.2 % vs. 23.7 % in the control group).Supplementation was manifested more markedly by pregnancies in the group of non-smokers (57.9 % vs. 31.6 % in the control group). The more than threefold number of non-smoking women who became pregnant after successful treatment of infertility (44.7 %) as compared with smokers (13.2 %) is an obvious reason why infertility treatment should be conditioned by abandonment of smoking.

        Key words: smoking - female infertility - ascorbic acid - assisted reproduction