OPS 15: Chemicals and pregnancy, Room 114, Floor 1, August 26, 2019, 10:30 AM - 12:00 PM Background/Aim: Parabens are commonly used as antimicrobial preservatives in cosmetics, pharmaceuticals, food and beverage processing. Widespread human exposure to parabens has been recently documented, and some parabens have demonstrated adverse effects on female reproduction in animal studies. Despite the widespread usage of parabens in personal care products little is known about their effect on female fertility. The aim of this study was to evaluate the association between environmental exposure to parabens and parameters of ovarian reserve. Methods: Urine samples collected from 511 female who attended the infertility clinic for diagnostic purposes were analyzed for five parabens concentrations using a validated gas chromatograohy ion-tap mass spectrometry method. Parameters of ovarian reserve were: follicle-stimulating hormone (FSH), antral follicle count (AFC), estradiol (E2) and anti-Müllerian hormone (AMH) levels. Results: In multivariate linear regression models adjusted for age, smoking and BMI only propyl paraben (PP) decrease antral follicle count (p=0.04), estradiol level (p=0.04) and increase the FSH concentration (p=0.028). Methyl (MP), ethyl (EP), butyl (BP) and isobutyl (iBuP) parabens were not associated any with parameters of ovarian reserve. These findings suggest that exposure to PP may adversely affect ovarian reserve, one of the predictor of female fertility among women attending a fertility clinic. Conclusions: PP may be associated with diminished ovarian reserve. As this is one of the first study on this topic, so the observation of the relationship between parabens and ovarian reserve warrants further investigation.