Ovarian cystectomy is commonly performed to treat benign ovarian cysts, but might cause inadvertent damage to normal ovarian tissue, thereby influencing a woman’s ovarian reserve. Ovarian reserve is defined as the existent quantitative and qualitative supply of follicles which are found in the ovaries that can potentially develop into mature follicles which in effect determine a woman’s reproductive potential. It is commonly quantified by the levels of serum FSH and recently by total antral follicle count (2.0-10.0 mm follicles in both ovaries) and AMH levels. These tests however have inherent biological variation in relation to menstrual cycle and ageing; and are also influenced by the intra- and inter-observer variations. The aim of this thesis was to develop a reliable method of examining the effect of ovarian cystectomy on ovarian reserve. I began by examining the ultrasound markers of ovarian reserve. AFC is measured using 2D ultrasound and there is some evidence that 3D ultrasound can make more reliable counts than 2D. I examined the reliability of these two methods and compared them to a new 3D assisted method, SonoAVC which is designed to make automated AFC. I found that the intra- and inter-observer reliability of SonoAVC in counting the number of antral follicles was superior to 2D and 3D manual methods. It however required post-processing of the counts by manually clicking on the antral follicles initially missed in the automated version, thereby making it a semi-automated method. I then compared 2D ultrasound to SonoAVC in measuring the size of antral follicles as there is increasing evidence that the small antral follicles might be more predictive of ovarian reserve. I found that SonoAVC measured the size of antral follicles significantly quicker than 2D and also that the number of small follicles measured by 2D were more than SonoAVC, thereby raising the possibility that 2D might overestimate the number of small antral follicles. I then studied the ability of antral follicle counts stratified by size in prediction of ovarian response and pregnancy. I found that the small antral follicles measuring between 2.0-4.0 mm were independent predictors of clinical pregnancy and ovarian response to assisted reproduction treatment. I then examined the AFCs of different sizes made by SonoAVC and 2D in bovine ovaries and compared to the follicles obtained by manually dissecting the follicles. I found that SonoAVC with post-processing significantly underestimated and 2D overestimated the number of antral follicles measuring 4.0mm or less, but both made comparable counts of follicles measuring more than 4.0mm when compared with the antral follicles dissected manually. However, the agreement with SonoAVC with post-processing was more than that with 2D. Having established that SonoAVC albeit with post-processing was the most reliable method in measuring the size of antral follicles, I began to examine the intra- and inter-cycle variation and compared to AMH. I found that the small antral follicle measuring 2.0-6.0 mm showed least intra-and inter-cycle variation and that it was comparable to AMH. The larger antral follicles showed significant intra-cycle variation but a non-significant inter-cycle variation in the early follicular phase of menstrual cycle. I also examined the inter-ovarian variation in the AFC’s and found that the small antral follicles measuring 2.0-6.0 mm again showed the least variation between ovaries within an individual. I was finally able to conclude that small antral follicles (≤6.0mm) measured using SonoAVC were the most reliable in prediction of ovarian reserve, and showed excellent correlation with AMH. Finally, I examined the effect of laparoscopic ovarian cystectomy on the ovarian reserve for up to 6 months post-operatively using AMH and small AFC measured by SonoAVC. I found that ovarian cystectomy significantly reduces ovarian reserve and that this effect may be more pronounced with cysts of endometriotic nature, followed by dermoid cysts. In summary, the effect of ovarian cystectomy on ovarian reserve is best quantified using AFC of small follicles measuring less than 6.0 mm as it provides reliable measures of ovarian reserve, has minimal biological variation and is comparable to AMH.

PCOS is one of the leading causes of infertility worldwide affecting 1 in 10 women of a reproductive age. One of the fundamental abnormalities in women with PCOS can be seen within hormonal irregularities, which may include hyperandrogenemia hyperinsulinemia and hyper secretion of luteinising hormone (LH); and it is hypothesised that a defect in steroid secreting ovarian theca cells is involved due to their contribution in non-PCOS hormonal synthesis. Hyperinsulinemia has been associated with hyper-androgenemia through in vitro studies of cultured PCOS theca, where it has been suggested that insulin increases progesterone and androstenedione secretion when compared to normal theca cells. Furthermore the augmented effects of LH and insulin have been seen to increase ovarian androgen synthesis in non-PCOS theca cultures whilst also increasing the expression of steroidogenic enzymes specific to the PI3-K pathway. Many theories exist toward the etiology of hyper androgenemia within PCOS. Very few approaches however, consider dysfunction in multiple tissue types that may contribute to hormonal imbalances. It is well established that an association between obesity and PCOS exists and it is often the first therapeutic target for re-establishing reproductive function in obese PCOS patients. Furthermore PCOS patients tend to show distinct gynoid body fat distribution, which is reported to aggravate PCOS symptoms. It was therefore valid to examine the involvement in adipocyte function and its contribution to androgen levels within peos. This is further supported through the link between metabolic disorders such as insulin resistance and hyperinsulinemia, and their associations to obesity. Our study employed isolated preadipocyte and thecal cultures with close regulation of the influential factors LH and insulin. In doing so, we analysed androgen synthesis through activation and expression of steroidogenic enzymes CYP17 within both normal and polycystic ovaries. This allowed us to examine whether protein/hormonal concentrations vary across non-PCOS and peos cultures. This also allowed us to examine the possibility of a novel pathway leading to localised adipocyte synthesis as well as pinpointing whether dysfunction existed within the insulin-signalling pathway of thecal androgen steroidogenesis. The work in this thesis shows that adipocytes derived from non-PCOS and PCOS women, maintained in vitro differ on the basis of their morphology, rates of differentiation and proliferation. Furthermore, they reacted differently under conditions designed to mimic PCOS in vitro (increased insulin and LH), with reduced non-PCOS proliferation, and increased non-PCOS androgen secretion on insulin treatment. We also found increased steroidogenic CYP 17 expression in PCOS cultures under insulin stimulation. However PCOS adipocytes androstenedione secretion remained unaffected by insulin stimulation and secreted constant levels of androstenedione similar to that seen by insulin stimulated non-PCOS adipocytes. Our examination of non-PCOS and PCOS primary thecal cultures showed CYP17 expression is increased in pcas theca under basal conditions and that increases in insulin and LH leads to increases in in vitro theca proliferation. These conditions were also seen to lead to significant increases in androstenedione secretion over non-PCOS thecal cultures, and the results suggest it to be acting through the PI3-K pathway. These results therefore point to a specific area of dysfunction that should be further targeted for examination. Furthermore, they suggest that an adipocyte dysfunction exists within PCOS patients that may significantly contribute to hyperandrogenemia through localized synthesis of androgens.

Polycystic ovarian syndrome (PCOS) is a highly prevalent heterogeneous syndrome associated with abdominal obesity, insulin resistance and the metabolic syndrome. This clustering of risk factors could translate into an adverse cardiovascular disease (CVD) risk profile. Endothelial dysfunction, an early barometer of CVD, has been exhibited by women with PCOS; however, it remains unclear whether endothelial dysfunction is independent of CVD risk factors in this population. Exercise training has been found to enhance conduit artery and cutaneous microvessel endothelial function in various populations. Nevertheless, limited research exists regarding the cardiovascular effects of exercise in PCOS, and its impact on endothelial function in conduit arteries and cutaneous microvessels, has not been explored. The primary aim of this thesis was to examine nitric oxide (NO)-mediated endothelial function at different levels of the vascular tree in women with PCOS and to establish whether supervised exercise training induces a therapeutic effect on endothelial function. A systematic review of published studies comparing FMD in PCOS and control women was conducted. Twenty-one published studies were identified for inclusion (pCOS n=908; controls n=566). Differences in FMD between PCOS and controls were synthesised and meta-regressed against BMI and age. The pooled mean FMD was 3.5% lower (95% CI=3.4, 3.7%; P < 0.001) in women with PCOS compared with controls; and the PCOS-mediated reduction in FMD was most evident in studies involving less obese women. PCOS [n=35, 28y (95% CI=26, 30), 31kg/m2 (95% CI=27, 35)] and control women [n=16, 32y (95% CI=30, 35), 30kg/m2 (95% CI=25, 32)] were recruited. Brachial artery endothelial function was assessed using flow-mediated dilation (FMD). Internal adipose tissue (lAT), subcutaneous (SAT), visceral (VAT) and abdominal SAT was quantified using whole body magnetic resonance imaging and IH magnetic resonance spectroscopy quantified liver and skeletal muscle fat. Cardiorespiratory fitness, glycaemic control, reproductive hormone and lipid profiles were also assessed. FMD was impaired in PCOS when compared with control women [-4.5% (95% CI=-6.3, -2.8), P < O.OOl]. When FMD was adjusted for individual differences in IAT [-4.3% (95% CI=-6.l, -2.4), P < O.OOl], VAT [-4.4% (95% CI=-6.3, -2.5), P < O.OOl] and insulin resistance [-3.9% (95% CI=-5.6, -2.1), P < O.OO 1], the difference in FMD between groups remained. Ten women with PCOS [27y (95% CI=23, 32), 31 kg/rrr' (95% CI=28, 34)] completed a 16-week supervised exercise programme while 7 women with PCOS [29y (95% CI=24, 35), 35kg/m2 (95%CI=31, 40)] opted for conventional care and followed simple lifestyle advice. Exercise training improved FMD to a greater degree than conventional care [3.4% (95% CI=1.8, 5.1), P > 0.0005] and in parallel greater improvements in cardiorespiratory fitness were observed with exercise [4.7ml/kg/min (95% CI=1.4, 7.9), P=0.005]. These changes with exercise occurred independently of changes in VAT, SAT or insulin resistance. NO-mediated vasodilation in the cutaneous microvessels was examined in 11 PCOS [29y (95% CI=25, 34), 34kg/m2 (95% CI=30, 38)] and 6 control women [29y (95% CI=21, 37), 34kg/m2 (95% CI=28, 39)] using laser Doppler flowmetry combined with intra-dermal microdialysis of L-NG-monomethyl arginine to assay the NO dilator system in response to incremental local heating of the forearm. Six women with PCOS [30y (95% CI=22, 37), 31kg/m2 (95% CI=25, 37)] then undertook a 16-week exercise-training programme. Nitric oxide contribution was attenuated in women with PCOS at peak heating [-16.0CVCmax (95% CI=-32.5, 0.6), P=0.05] and during prolonged maximal heating [-15.4CVCmax (95% CI=- 29.6, -1.3), P=0.04], compared with control women. Cardiorespiratory fitness improved by 5.0ml/kg/min (95% CI=0.9, 9.2) following exercise training (P=0.03). This was accompanied by increased NO contribution to cutaneous blood flow between 36.5-42°C (P < 0.05), at peak heating [19.6CVCmax (95% CI=4.3, 34.9), P=0.02] and during prolonged maximal heating [17.1CVCmax (95% CI=2.2, 32.2), P=0.03]. The findings from this thesis suggest that endothelial dysfunction is an intrinsic characteristic of PCOS and that supervised exercise training enhances endothelial function in both conduit vessels and cutaneous microvessels, independent of adiposity or traditional CVD risk factors. The direct impact of exercise training on the vasculature of women with PCOS may decrease the risk of CVD morbidities, such as hypertension, and consequently reduce cardiovascular mortality in post-menopausal years.

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Το σύνδρομο πολυκυστικών ωοθηκών (PCOS) αποτελεί την πιο συχνή ενδοκρινολογική διαταραχή των γυναικών αναπαραγωγικής ηλικίας που χαρακτηρίζεται από κεντρικού τύπου παχυσαρκία, ακμή, υπερτρίχωση και διαταραχές των εμμηνορησιακών κύκλων που οφείλονται στην υπερανδρογοναιμία και την χρόνια ανωοθυλακιορρηξία. Οι γυναίκες με PCOS αναπτύσσουν και μεταβολικού τύπου διαταραχές όπως η υπερινσουλιναιμία λόγω αντίστασης στην ινσουλίνη, η υπέρταση, ο σακχαρώδης διαβήτης, η δυσλιπιδαιμία και το μεταβολικό σύνδρομο. Τα τελευταία χρόνια γίνονται πολλές γενετικές μελέτες προκειμένου να προσδιορισθούν οι μοριακοί γενετικοί μηχανισμοί που εμπλέκονται στην παθογένεια του ΣΠΩ. Ένας σημαντικός ρυθμιστής της ωοθυλακιογένεσης που πιθανόν να παίζει ρόλο στην παθοφυσιολογία του ΣΠΩ είναι η αντιμυλλεριανική ορμόνη (ΑΜΗ). Eντός του εξωνίου 1 του γονιδίου της ΑΜΗ εδράζεται ο πολυμορφισμός Ιle49Ser (ref SNPID:rs10407022) που συνίσταται στην αλλαγή μιας βάσης θυμίνης (T) από γουανίνη (G) δημιουργώντας τρεις γονότυπους: ομοζυγώτες GG, oμοζυγώτες TT, ετεροζυγώτες GT. Δεδομένου του ρόλου της ΑΜΗ στην παθοφυσιολογία του συνδρόμου των πολυκυστικών ωοθηκών αλλά και της ενδεχόμενης χρήσης της ως διαγνωστικό και προγνωστικό δείκτη του συνδρόμου, ο πολυμορφισμός Ιle49Ser έχει καταστεί αντικείμενο μελέτης. Στην παρούσα μελέτη προσδιορίστηκε ο πολυμορφισμός Ιle49Ser σε 111 γυναίκες με ΣΠΩ και 67 υγιείς μάρτυρες . Από τη στατιστική ανάλυση δεν προέκυψε κάποια στατιστικά σημαντική διαφορά στη συχνότητα των γονοτύπων του πολυμορφισμού Ile49Ser του γονιδίου της ΑΜΗ ανάμεσα στις γυναίκες με ΣΠΩ και του υγιούς πληθυσμού ελέγχου. Από τη στατιστική ανάλυση, επίσης, δεν προέκυψε συσχέτιση των γονοτύπων με κάποια από τις ορμονικές ή κλινικές παραμέτρους των γυναικών με ΣΠΩ. Η απουσία συσχέτισης του πολυμορφισμού Ile49Ser με αυξημένο κίνδυνο για ΣΠΩ δείχνει ότι το σηματοδοτικό μονοπάτι της ΑΜΗ εμπλέκεται στην παθογένεια του συνδρόμου με έναν έμμεσο τρόπο. Ωστόσο περισσότερες μελέτες είναι απαραίτητες προκειμένου να διαλευκανθεί ο ρόλος της ΑΜΗ στην ανθρώπινη ωοθυλακιογένεση, όπως και στην παθοφυσιολογία του συνδρόμου των πολυκυστικών ωοθηκών. / The polycystic ovary syndrome (PCOS) is the most common endocrine disorder of women of reproductive age, characterized by central obesity, acne, hirsutism and disorders of menstrual cycles due to hyperandrogonemia and chronic anovulation. Women with PCOS develop type and metabolic disorders such as hyperinsulinemia due to insulin resistance, hypertension, diabetes mellitus, dyslipidemia and metabolic syndrome. Over the last decade there are an increasing number of studies conducted in order to identify the molecular genetic mechanisms that are involved in the pathogenesis of PCOS. AMH seems to be an important regulator of follicle development and may also play a significant role in the pathogenesis of PCOS. The polymorphism Ile49Ser (ref SNPID:rs10407022) is located in exon 1 of AMH gene and results from the conversion of thymine (T) to guanine (G) giving three genotypes: homozygotes TT, GG and heterozygotes GT. Taken as granted the role of AMH in the pathophysiology of PCOS and the possible use of AMH levels as a diagnostic and prognostic marker of the syndrome, recent studies concern the involvement of IIe49Ser polymorphism. The precent study identified the polymorphism Ile49Ser in a cohort of 111 women with PCOS and 67 controls. Genotype frequencies for the AMH Ile49Ser polymorphism were similar in PCOS women and controls. In addition, AMH Ile49 Ser variant was not associated with clinical or hormonal parameters of PCOS women. The absence of an association of AMH Ile49Ser polymorphism with susceptibility to PCOS indicates that the AMH signaling pathway is not directly involved in the pathophysiology of PCOS. More studies should be carried out in order to determine the role of AMH in human ovarian physiology.

Το σύνδρομο πολυκυστικών ωοθηκών (PCOS) αποτελεί την πιο συχνή ενδοκρινολογική διαταραχή των γυναικών αναπαραγωγικής ηλικίας που χαρακτηρίζεται από κεντρικού τύπου παχυσαρκία, ακμή , υπερτρίχωση και διαταραχές των εμμηνορησιακών κύκλων που οφείλονται στην υπερανδρογοναιμία και την χρόνια ανωοθυλακιορρηξία. Οι γυναίκες με PCOS αναπτύσσουν και μεταβολικού τύπου διαταραχές όπως η υπερινσουλιναιμία λόγω αντίστασης στην ινσουλίνη, η υπέρταση, ο σακχαρώδης διαβήτης, η δυσλιπιδαιμία και το μεταβολικό σύνδρομο. Σημαντικό ρόλο στην παθοφυσιολογία της των παραπάνω μεταβολικών διαταραχών ασκεί το σύστημα Ρενίνης-Αγγειοτενσίνης-Αλδοστερόνης (Renin-Angiotensin-Aldosterone System – RAAS) που διακρίνεται σε ενδοκρινές κι ιστικό. Στο ιντρόνιο 16 του γονιδίου του ενζύμου ACE(17q23) έχει βρεθεί ο πολυμορφισμός I/D που προκύπτει από την παρουσία ( Insertion– I) ή την απουσία (Deletion–D) μιας Αlu αλληλουχίας μήκους 287 bp, δημιουργώντας τρείς διακριτούς γονότυπους: II, ID και DD Με δεδομένο το ρόλο του συστήματος RAAS σε σχέση με τους παράγοντες κινδύνου για καρδιαγγειακή νόσο και κυρίως με την αντίσταση στην ινσουλίνη, ο ρόλος του πολυμορφισμού ACE I/D έχει καταστεί αντικείμενο μελέτης ως προς την εκδήλωση καρδιαγγειακών συμβαμάτων. Στην παρούσα μελέτη προσδιορίστηκε ο πολυμορφισμός ACE I/D σε 156 φυσιολογικές γυναίκες και σε 212 γυναίκες με την πιο βαριά μορφή του συνδρόμου πολυκυστικών ωοθηκών που είναι η ύπαρξη βιοχημικής υπερανδρογοναιμίας και χρόνιας ανωοθυλακιορηξίας. Το συμπέρασμα μετά τη στατιστική ανάλυση ήταν ότι ο γονότυπος ΙΙ συνδέεται στατιστικώς σημαντικά με την την αντίσταση στην ινσουλίνη κι ο γονότυπος ΙD με τα επίπεδα της 17-OH προγεστερόνης, πρόδρομης ορμόνης κατά την βιοσύνθεση των ανδρογόνων που ίσως σημαίνει με τοπικά αυξημένη ενεργότητα του RAS. Tα ευρήματα αυτά ανάγουν τον πολυμορφισμό της ACE σε ένα πιθανά πολύτιμο δείκτη αυξημένου καρδιαγγειακού κινδύνου στις γυναίκες με PCOS. / The polycystic ovary syndrome (PCOS) is the most common endocrine disorder of women of reproductive age, characterized by central obesity, acne, hirsutism and disorders menstrual cycles due to hyperandrogonemia and chronic anovulation. Women with PCOS develop type and metabolic disorders such as hyperinsulinemia due to insulin resistance, hypertension, diabetes mellitus, dyslipidemia and metabolic syndrome. Important role in the pathophysiology of these metabolic disorders has the renin-angiotensin-aldosterone system (Renin-Angiotensin-Aldosterone System - RAAS), which is divided into endocrine and tissue. In intron 16 of the gene of the enzyme ACE (17q23) has found a polymorphism I / D resulting from the presence (Insertion-I) or absence (Deletion-D) of an Alu sequence length of 287 bp, creating three distinct genotypes: II,ID,DD. Given the role of the RAAS system in relation to risk factors for cardiovascular disease and especially with insulin resistance, the role of polymorphism ACE I / D has become a subject of study as to the occurrence of cardiovascular events. This study identified a polymorphism ACE I / D in 156 healthy women and 212 women with the most severe form of polycystic ovarian syndrome is the presence of biochemical hyperandrogonemia and chronic anovulation. The conclusion after statistical analysis was that the II genotype is associated statistically significant with insulin resistance and ID genotype with levels of 17-OH progesterone hormone precursor in the biosynthesis of androgens which it might means locally increased activity of RAS. These findings suggest the polymorphism of the ACE in a potentially valuable indicator of increased cardiovascular risk in women with PCOS.

Το σύνδρομο των πολυκυστικών ωοθηκών (PCOS) είναι ίσως η συχνότερη διαταραχή των γυναικών αναπαραγωγικής ηλικίας. Οι κύριες κλινικές εκδηλώσεις του συνδρόμου είναι η υπερανδρογοναιμία και η χρόνια ανωοθυλακιορρηξία, ενώ σχετίζεται σε μεγάλο βαθμό με την παχυσαρκία και την αντίσταση στην ινσουλίνη. Η αντίσταση στην ινσουλίνη έχει ένα σημαντικό ρόλο τόσο ως αίτιο όσο και ως αποτέλεσμα του συνδρόμου. Στις γυναίκες τόσο η υπερινσουλιναιμία όσο και η υπερανδρογοναιμία σχετίζεται με αυξημένο καρδιοαγγειακό κίνδυνο. Το PCOS σχετίζεται με αυξημένο καρδιοαγγειακό κίνδυνο, ενώ τόσο η αλλαγή τρόπου ζωής και η φαρμακολογική παρέμβαση έχει δειχθεί ότι βελτιώνει την υπερανδρογοναιμία και την υπογονιμότητα και ελαττώνει τον καρδιοαγγειακό κίνδυνο. Μαζί με τους κλασικούς καρδιοαγγειακούς παράγοντες κινδύνου, αιμοδυναμικές και αιματολογικές μεταβλητές παίζουν σημαντικό ρόλο στην παθογένεση της αθηρωσκλήρυνσης. Η γλοιότητα του πλάσματος είναι σημαντική αιματολογική μεταβλητή και εξαρτάται απο μακρομόρια όπως το ινωδογόνο, οι ανοσοσφαιρίνες και οι λιποπρωτεϊνες. Ο σκοπός της παρούσης μελέτης ήταν να ερευνήσει τις μεταβολές της γλοιότητας του πλάσματος σε γυναίκες με PCOS και την συσχέτιση τους με την υπερανδρογοναιμία, την παχυσαρκία και την αντίσταση στην ινσουλίνη. Η μελέτη συμπεριέλαβε 96 ασθενείς με PCOS και 72 γυναίκες με φυσιολογική έμμηνο ρύση ως ομάδα ελέγχου. Η γλοιότητα πλάσματος ήταν 1.243±0.670 mm2/s στην ομάδα ελέγχου (n=72), και 1.250±0.079 στιν γυναίκες με PCOS (n=96) (p=0.524). Η γλοιότητα του πλάσματος εμφάνισε σημαντική συσχέτιση με BMI (b=0.315, p=0.013), Ολικές Πρωτείνες (b=0.348, p=0.005), AUCIns (b=0.320, p=0.011). Στις γυναίκες με PCOS με αντίσταση στην ινσουλίνη (PCOS-IR) η γλοιότητα του πλάσματος ήταν 1.300 ± 0.055 mm2/s, ενώ στις γυναίκες με PCOS χωρίς αντίσταση στην ινσουλίνη (PCOS-ΝIR) η γλοιότητα του πλάσματος ήταν 1.231± 0.49 mm2/s (p=0.004). Στη συνέχεια χωρίσαμε όλες τις γυναίκες με PCOS σε 2 υποομάδες: αυτές με BMI<25 και αυτές με BMI>25. Η γλοιότητα πλάσματος ήταν 1.235±0.786mm2/s στις γυναίκες με PCOS και BMI<25, και 1.273±0.756mm2/s στις γυναίκες με PCOS και BMI>25 (p=0.024). Σε νέες γυναίκες με PCOS η αύξηση της γλοιότητας του πλάσματος συσχετίσθηκε με την παχυσαρκία και την αντίσταση στην ινσουλίνη. Συμπερασματικά στις νέες γυναίκες με PCOS η γλοιότητα του πλάσματος επιδεινώθηκε από την αντίσταση στην ινσουλίνη. Καθώς η αυξημένη γλοιότητα του πλάσματος είναι ένας πρώιμος παράγοντας κινδύνου για καρδιοαγγειακή νόσο, ο κλινικός χειρισμός των νέων υπέρβαρων γυναικών με PCOS θα πρέπει πάντα να περιλαμβάνει μία μείωση του σωματικού τους βάρους και τη λελογισμένη και με προσοχή χρήση των αντισυλληπτικών δισκίων ως θεραπευτική προσέγγιση. / Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility in women. PCOS is characterized by hirsutism, anovulation, hyperandrogenemia and is also highly associated with obesity and insulin resistance. Insulin resistance plays a significant role, both as a cause and as a result of the syndrome. Both hyperinsulinemia and androgen excess in women is associated with increased cardiovascular risk. PCOS is linked to cardiovascular disease, while, altering lifestyle or pharmacological intervention has been shown to improve hyperandrogenism and infertility and reduce cardiovascular risk. Along with classic cardiovascular risk factors, hemodynamic and hemorheologic variables play an important role in the pathogenesis of atherosclerosis. Plasma viscosity is an important hemorheologic variable and is mainly determined by several macromolecules, including fibrinogen, immunoglobulins, and large lipoproteins. Our objective was to investigate plasma viscosity in women with PCOS. The acquired data were tested for association with hyperandrogenemia, obesity and insulin resistance in PCOS patients. The study included 96 young PCOS women and 72 healthy controls. Plasma viscosity was 1.243±0.670 mm2/s in the control group and 1.250±0.079 in PCOS women (p=0.524). Total protein (B=0.348, p=0.005), AUC for Insulin (B=0.320, p=0.011) and BMI (B=0.315, p=0.013) were proven to be significantly correlated to plasma viscosity. Plasma viscosity was significantly increased in PCOS women with Insulin Resistance (IR) compared to matched for age and BMI PCOS women without IR (1.300±0.055 mm2/s versus 1.231±0.049 mm2/s) (p=0.004). Then we divided all PCOS women in two separate groups, lean PCOS with BMI<25 and obese PCOS with BMI>25. Plasma viscosity was 1.235±0.786mm2/s in PCOS women with BMI<25, in the group of women was and 1.273±0.756mm2/s in PCOS women with BMI>25 (p=0.024). Young PCOS women presented a plasma viscosity which was increased by obesity and IR. In conclusion, young PCOS women presented a plasma viscosity which was deteriorated by IR. As increased plasma viscosity is an early risk factor for cardiovascular disease, clinical management of young overweight PCOS women with IR should always include a serious reduction in body weight and the use of oral contraceptive treatment with cautious.