OBJECTIVE: To evaluate transforming growth factor beta1 (TGF-beta1) and glycosaminoglycans (GAG) changes in human plasma and urine during the menstrual cycle, IVF-ET, and pregnancy. DESIGN: Prospective clinical study. SETTING: University hospital. PATIENT(S): Thirteen women with apparently normal menstrual cycle (group 1); 18 women undergoing IVF-ET (group 2); and 14 low-risk pregnant women (group 3). INTERVENTION(S): We assayed plasma and urine concentrations of TGF-beta1, urine content, and distribution of GAG. Blood and urine samples were collected during days 2 to 3, 12 to 13, and 23 to 24 in group 1; in group 2, samples were obtained at menstrual phase, oocyte pick-up day, and 15 days after ET; in group 3, samples were obtained during gestational weeks 10-12, 22-24, and 30-32 and 1 month after delivery. MAIN OUTCOME MEASURE(S): Changes in TGF-beta1 and GAG content. RESULT(S): The mean value of total urinary trypsin inhibitor/chondroitin sulfate (UTI/CS) showed a distinct peak at day 12 of the menstrual cycle in the fertile women in whom we monitored the ovulatory period. In the IVF-ET group, GAG distribution and TGF-beta1 levels showed significant differences during the cycle. We observed increased levels of plasma TGF-beta1 15 days after ET. A significant increase of total UTI/CS value with increasing gestation was detected. CONCLUSION(S): Transforming growth factor beta1 and GAG levels could represent an additional tool to monitor reproductive events and could be useful, noninvasive markers of ovulation and ongoing pregnancy.