The effect of follicle maturing drugs on side of ovulation in successive cycles.

Our previous study has demonstrated that ovulation in unstimulated cycles is random with an equal likelihood of ipsilateral or contralateral ovulation occurring in the following cycle. This study evaluated women taking ovulation-inducing drugs to see if the side of ovulation in the preceding cycle has an influence on the side of ovulation in the succeeding cycle. Ovulatory patterns in consecutive pairs of cycles in anovulatory women treated with ovulation-inducing drugs were evaluated through sonographic studies of follicular maturation. The results demonstrated that when unilateral ovulation occurred, there was an equal likelihood of ipsilateral or contralateral ovulation in the succeeding cycle. However, ovulation-inducing drugs increase the incidence of bilateral or multiple ovulation.     

Involvement of leukocytes and cytokines in the ovulatory process and corpus luteum function

The role of leukocytes and cytokines in ovarian physiology isnow established, although the function of each cell type andcytokine remains to be determined in detail. Current knowledgeof these effects on follicle development, ovulation, luteinizationand luteotrophic process and luteolysis is reviewed. It is possiblethat further research will help to unravel some of the clinicalmysteries in ovarian function, including polycystic ovary syndrome,premature menopause, ovulatory disorders, and luteal phase defect.Furthermore, the increasing use of cytokines and their antagonistsin clinical practice may have significant effects upon reproductivefunction.     

Side of ovulation and cycle characteristics in normally fertile women

This study was undertaken to establish whether ovulation in humans alternates consistently from right to left ovary in successive cycles and whether the site of ovulation affects the next cycle length or the hormonal profiles. A total of 199 cycles in 80 normally fertile women were studied. The volunteers were monitored with ultrasonography to determine the day and side of ovulation and to calculate follicular and luteal phase lengths. Urinary hormone concentrations were also assayed. Right-sided ovulations occurred in 104 of the 199 cycles (52.3%; not significantly different from 50%). Alternate ovulations occurred in 61 of the 119 pairs of succeeding cycles (51.3%, not significant). The follicular phase length in contralateral ovulation (14.59 +/- 0.33 days; mean +/- SEM) did not differ significantly from that of ipsilateral ovulation (14.59 +/- 0. 37 days). There were also no significant differences in urinary concentrations of oestrone-3-glucuronide, pregnanediol-3alpha glucuronide, follicle stimulating hormone, and luteinizing hormone between ipsilateral and contralateral ovulation in either early follicular, peri-ovulatory or luteal phase of the cycle. It is concluded that in normally fertile women, the cycle length and the hormonal profile are independent of the, most probably random, site of ovulation.     

生后大鼠发育不同时期各级卵泡凋亡的观察

目的：观察研究生后不同阶段大鼠卵巢卵泡的生长发育与卵泡凋亡的关系、凋亡过程及规律，探索性激素血液浓度变化与卵泡凋亡的内在联系。方法：用DNA缺口原位末端标记检测法，对生后20-140天不同阶段大鼠卵巢卵泡的生长发育及卵泡凋亡进行了光镜观察，同时对生后各阶段鼠血液孕激素(progesterone P）,卵泡刺激素（follicle stimulating hormone FSH)、黄体生成素(luteinizing lormone LH)、雌二醇(estradiol E2)浓度进行放免检测。结果：生后20天鼠卵泡即可见到凋亡发生，卵泡凋亡始于卵母细胞，继则是与其相邻的卵泡细胞，卵泡细胞的凋亡从内向外依次发生。卵泡的凋亡数目随着卵巢的生长发育而逐渐增多，生后40天可见到黄体细胞凋亡发生，至50-60天可见到卵泡膜内膜细胞凋亡及白体形成，出生80天后卵巢发育已完全成熟，此时卵泡的凋亡数也达到了高峰；放免结果经方差分析显示孕激素P＞0．05，差异显著，推测其浓度变化与卵泡凋亡有内在联系。     

Functional life-span of the dominant follicle in pharmacologically induced anovulatory cycles

With the purpose of measuring the duration of the functionallife-span (FLS) of the anovulatory follicle in women under continuouslow-dose progestogen treatment, the oestradiol curve of Norplantimplant users was retrospectively analysed. From all the datacollected during the previous 5 years at the Department of BiomedicalResearch at the Family Planning Clinic of Profamilia, SantoDomingo, Dominican Republic, data from all 29 Norplant implantusers showing follicular activity without luteal activity wereselected for this retrospective analysis. Serial blood samplingtwice or three times a week for 5 or 6 consecutive weeks hadbeen taken in all subjects. The duration of the FLS of the dominantfollicle in anovulatory cycles was defined as the period fromthe first day of ascending oestradiol curve until the day precedingonset of menses. The mean FLS of the dominant follicle in anovulatorycycles under continuous low-dose progestogen administrationwas 21.1 4.2 days, independently of the length of the menstrualcycle. The duration of the FLS of the anovulatory dominant follicleappears not to be different from the duration of a normal follicle/corpusluteum unit.     

Ovary and Ovulation: Home ovulation testing In a donor insemination service

The use of home ovulation testing kits in donor insemination(DI) has been proposed to increase patient and clinic conveniencewhile not compromising fecundity rates. Such a system was introducedinto our Dl service in December 1994, and we here report anaudit of experience over 6 months. Patients were offered homeor laboratory luteinizing hormone (LH) testmg, and those requestinghome testing were asked to store an aliquot of tested urinefor subsequent assay in the laboratory allowing retrospectiveanalysis of the accuracy of cycle timing. Insemination usingcryopreserved semen was performed on the day home testing predictedovulation, or on the day an LH surge was detected in the laboratory,and on the following day. Pregnancy rates were significantlyreduced in home testers: 3.4% per cycle (174 cycles, 64 women)versus 12.7% (110 cycles, 53 women) over the same time period(P<0.005, 95% confidence interval 6.5–18.9). Urinesamples from 140 cycles from 51 women using home testing wereanalysed. There were insufficient data in nine to allocate thecycle. Of home tested cycles, 37 (28%) were inseminated on aday other than the first day of the LH surge. In 13 of theseinsemination was performed after the first day of the LH surge.Incorrect treatment was associated with high baseline LH, butthose with ‘late’ treatment had low basal LH concentrations,similar to those correctly treated. Analysis of individual urinesamples showed that the positive predictive value of home testingwas 72%. These results suggest that home ovulation testing resultsin reduced chance of pregnancy, with increased frustration forboth patients and clinic staff. This may be particularly soin women with high baseline LH concentrations.     

Endocrinology: The role of luteinizing hormone in human follicle development and oocyte fertility: evidence from in-vitro fertilization in a woman with long-standing hypogonadotrophic hypogonadism and using recombinant human follicle stimulating hormone

To evaluate the relative importance of follicle stimulatinghormone (FSH) and luteinizing hormone (LH) in follicular developmentand oocyte fertility in the human species, the use of recombinanthuman FSH, human menopausal gonadotrophin (HMG), and very highlypurified urinary human FSH (FSH-HP) plus oestradiol valeratefor ovarian stimulation and in-vitro fertilization (IVF) werecompared in three cycles in a woman with isolated congenitalgonadotrophin deficiency who had never been treated with ovarianstimulating agents. The total number of ampoules of gonadotrophinsused was lower in the HMG treatment cycle. Ovarian responseand IVF outcome in the three treatment cycles were as follows:(i) HMG cycle: normal follicular growth, normal pattern of oestradioland inhibin through the menstrual cycle, high fertilizationrate (93%); (ii) recombinant FSH cycle: normal follicular growth,low oestradiol and abnormal inhibin, finally poor rate of fertilization(28%); (iii) FSH-HP plus oestradiol valerate cycle: normal folliculargrowth, normal pattern of inhibin and poor fertilization rate(27%). Luteal plasma progesterone concentrations were much higherin the HMG treatment cycle. This case shows that FSH is theonly factor required in order to induce follicular growth inthe human, although LH or a product derived from its actionmay assist in order to achieve full follicular maturity andoocytes capable of fertilization. Though oestradiol might havea mediatory role in the process of follicular maturation, ourresults favour a direct primary role of LH in complete maturationof the follicle.     

Endocrinology: Luteal phase oestradiol and progesterone levels are stronger predictors than follicular phase follicle stimulating hormone for the outcome of in-vitro fertilization treatment in women with tubal infertility

Basal follicle stimulating hormone (FSH) in a natural cycle,FSH on cycle days 3 and 10 in a domiphene citrate-stimulatedcycle and oestradiol and progesterone area under the curve (AUC)in the luteal phase of the ciomiphene citrate-stimulated cyclewere evaluated as hormonal predictors for the outcome of FVFtreatment in 53 normally cycling women with tubal infertility.The pregnant women had significantly fewer treatment cycles(P < 0.001) and needed fewer ampoules of gonadotrophins (P< 0.001). They also had more oocyte retrievals (P < 0.001),more oocytes per retrieval (P < 0.01), higher fertilizationrate (P < 0.001) and more replaced pre-embryos per replacement(P < 0.01) as compared with non-pregnant women. Significantdifferences were found in FSH concentrations on cycle days 3(P < 0.05) and 10 (P < 0.001) after domiphene citratestimulation and for oestradiol and progesterone AUC in the lutealphase (P < 0.001) between those women who became pregnantand those who did not become pregnant after IVF treatment Lutealoestradiol and progesterone had considerably stronger predictivevalue for the outcome of IVF treatment as compared to basalFSH and domiphene citrate challenge test.     

Controlled ovulation of the dominant follicle: a critical role for LH in the late follicular phase of the menstrual cycle

BACKGROUND: A method was sought to control ovulation of the dominant follicle and to test the importance of LH during the late follicular phase of the menstrual cycle. Menstrual cycles of rhesus monkeys were monitored, and treatment initiated at the late follicular phase (after dominant follicle selection, before ovulation). METHODS: The 2-day treatment consisted of GnRH antagonist plus either r-hFSH and r-hLH (1:1 or 2:1 dose ratio) or r-hFSH alone. In addition, half of the females received an ovulatory bolus of hCG. RESULTS: When treatment was initiated at estradiol levels >120 pg/ml, neither the endogenous LH surge, ovulation nor luteal function were controlled. However, when treatment was initiated at estradiol levels 80-120 pg/ml using either 1:1 or 2:1 dose ratios of FSH:LH, the LH surge was prevented, and ovulation occurred following hCG treatment. FSH-only treatment also prevented the LH surge, but follicle development appeared abnormal, and hCG failed to stimulate ovulation. CONCLUSIONS: Control over the naturally dominant follicle is possible during the late follicular phase using an abbreviated GnRH antagonist, FSH+LH protocol. This method offers a model to investigate periovulatory events and their regulation by gonadotrophins/local factors during the natural menstrual cycle in primates.     

Anovulations in an ovary during two menstrual cycles enhance the pregnancy potential of oocytes matured in that ovary during the following third cycle

The aim of this study was to test whether ovulation from anovary affects the health of oocytes from dominant folliclesin that ovary two cycles later. A total of 80 women each withtwo intact ovaries underwent 270 treatment cycles (155 naturalcycles and 115 clomiphene citrate cycles) all showing unilateralovulation. The results from the in-vitro fertilization (IVF)treatment were grouped according to whether ovulation (O) oranovulation (A) (no ovulation) was observed in the ovary withdominant follicle during the treatment cycle in the previoustwo cycles: O-O, A-O, O-A and A-A (previous second cycle-previousfirst cycle). The rate of pre-embryo formation in A-A was significantlyhigher than that of O-A. The pregnancy rate in A-A (29%) wasalso higher than those of O-A (13%), A-O (9%) and O-O (5%).These rates increased from O-O to A-A as the number of previousovulations in an ovary decreased. The presence of a corpus luteumand/or a dominant follicle is likely to exert local negativeeffects on the health of the oocyte contained in the follicleselected to ovulate up to two cycles later. Anovulations inan ovary for two menstrual cycles may therefore provide improvedconditions for the development of a healthier oocyte with anincreased pregnancy potential.     

Expression and regulation of Sprouty-2 in the granulosa-lutein cells of the corpus luteum

Growth factor signalling has important modulatory roles in the process of human follicular growth, oocyte maturation and corpus luteum (CL) formation. Recently, Sprouty-2, an inhibitor of receptor tyrosine kinase (RTK) signalling pathway was advocated as a marker of oocyte competence in the bovine ovary. We sought to study Sprouty-2 expression and regulation in the human ovary. RT-PCR was used to detect Sprouty-2 mRNA in human granulosa-lutein cells (GLC) collected from follicular aspiration of IVF patients. The effect of epidermal and fibroblast growth factors (EGF and FGF) on Sprouty-2 mRNA expression in GLC was studied using quantitative real-time PCR. Immunohistochemistry was performed on cultured GLC, human CL and stimulated rat ovary sections. Sprouty-2 mRNA was expressed in human GLC. EGF and basic FGF, but not FGF4 and FGF10, increased Sprouty-2 mRNA expression in GLC. The Sprouty protein was localized to GLC of early and late human CL but not to the theca cell layer. Immunostaining of developing rat CL confirmed the temporal and spatial expression of Sprouty in humans. The detection of Sprouty-2 mRNA and protein in human GLC may suggest a role for Sprouty-2 during the final stages of follicle maturation and CL formation.     

Current concepts of the roles of follicle stimulating hormone and luteinizing hormone in folliculogenesis

Around 400 follicles sequentially mature and ovulate duringan average women‘s reproductive lifetime. From birth tothe menopause, the other 99.98% of her follicles begin developmentbut never complete it. Instead they default to atresia due toinadequate stimulation by follicle stimulating hormone (FSH).Follicular growth to the stage of antrum formation (0.25 mmdiameter) is independent of gonadotrophic stimulation. Antrumformation and further growth to the stage at which folliclesbecome potentially able to begin pre-ovulatory development (2–5mm diameter) require tonic stimulation by FSH. Before onsetof puberty, blood concentrations of FSH do not rise sufficientlyto sustain development beyond this stage, therefore all antralfollicles become atretic. After puberty, as each menstrual cyclebegins, FSH concentrations rise beyond a critical ‘threshold’and multiple follicles are recruited to begin pre-ovulatorydevelopment. Due to increases in its responsiveness to FSH andluteinizing hormone (LH), one of these follicles becomes selectedto ovulate while the remainder become atretic. At mid-follicularphase, the dominant follicle reaches 10 mm in diameter and increasinglysynthesizes oestradiol. Tonic stimulation by FSH and LH, underpinnedby local paracrine signalling, maintains oestrogen secretionby the dominant follicle, which grows to 20 mm in diameter beforeit ovulates in response to the mid-cycle LH surge. The development-relatedresponse to LH shown by the pre-ovulatory follicle raises thepossibility that exogenous LH might be used as an adjunct totherapy with exogenous FSH in clinical ovulation induction regimenswhere the aim is to induce monovulation.     

Localization and characterization of white blood cell populations within the human ovary throughout the menstrual cycle and menopause

The purpose of this investigation was to localize and characterizewhite blood cell populations in the human ovary through itsphysiological life cycle. Ovaries from 30 women of reproductiveage and from three post-menopausal women were embedded in paraffinor frozen. Clinical information and pathology review were usedto obtain accurate menstrual cycle information and to ensurethe absence of ovarian disease. Tissue sections were stainedfor leukocyte phenotypes and the numbers of white blood cellsin the ovary were semiquantitatively assessed by two separateexaminers using a 0–3 plus (+) scoring system. Our resultsdemonstrated that macrophages and T lymphocytes were the primaryimmune cells of the ovary, the concentrations of which weredependent on the location and stage of development of the structurescontaining leukocytes. Developing follicles contained few (+)macrophages located in the theca, while atretic follicles possessedmoderate (+ +) numbers in the granulosa and few ( + ) to moderate(+ +) numbers in the theca. Newly formed corpora lutea containedfew ( + ) macrophages, while regressing corpora lutea containedabundant (+ + +) numbers. Human leukocyte antigen (HLA)-DR positivecells were located predominantly at sites where macrophageswere present T lymphocytes were generally not present in thedeveloping follicle but focal, small (+) numbers were observedin blood vessels of the theca. Atretic follicles contained few( + ) T lymphocytes in the granulosa and few (+) to moderate( + +) numbers in the theca. Few (+ ) T lymphocytes were presentin new corpora lutea, while moderate (+ +) to abundant (+ ++) numbers were present in regressing corpora lutea. T lymphocytesat all sites were UCHLl positive. The CD4 (T helper) to CD8(T suppressor) ratio in the corpus luteum was 1: 1. B-lymphocytesand natural killer cells were generally absent in the pre-menopausalovary. Hie post-menopausal ovary, in contrast, only containedfew ( + ) macrophages, T lymphocytes and natural killer cellsin the stroma. In conclusion, our results indicate that thehuman ovary is an immunologicaUy dynamic tissue containing activatedmacrophages and T lymphocytes which provide an anatomical basisfor immunoendocrine interactions within the ovary.     

Few instead of many: human follicle collection from follicular aspirates at oocyte retrieval

BACKGROUND: The aim of this study was to determine if follicular aspirates obtained during oocyte retrieval for IVF were a good source of ovarian follicles for research purposes. METHODS: Follicular aspirates from 86 patients were collected and examined for the presence of follicles, and histological examination of tissue sample found was undertaken. RESULTS: Follicles were only obtained from aspirates of seven out of a total of 86 patients. From these samples a total of 14 follicles was found. The follicles were primordial, primary or secondary, 40-80 microm in diameter. Three of these recovered follicles were cultured and all degenerated within 2 days. In all aspirates some groups of granulosa cells that did not contain follicles or oocytes were found, as was vaginal epithelium that was also identified and verified by histology. CONCLUSIONS: Follicular aspirates are not a useful source of human follicles. Some structures found in the aspirates may be erroneously identified as follicles.     

The effect of accompanying dominant follicle development/ovulation on the outcomes of frozen-thawed blastocyst transfer in HRT cycle

The artificial regime was widespread used in frozen-thawed embryo transfer (FET). Some researchers asserted that if dominant follicles developed or ovulation occurred in hormone replacement FET cycles, this cycle should be cancelled because the fitting timing of transfer was hard to determine. In this study, we compared the difference between the outcome of frozen-thawed blastula transfer in hormone replacement treatment cycle (HRT) with or without dominant follicle development/ovulation. A total of 171 cases of frozen-thawed blastula transferred successfully in HRT cycle were retrospectively analyzed. Patients were divided into three groups according to dominant follicle development, ovulation or not: Group A, cycles without dominant follicle developing. Group B, cycles with dominant follicle developing but without ovulation. Group C, ovulated cycles. The results showed that there was no significant difference in the pregnancy rates or other parameters among the three groups, but the abortion rate was higher in group C than those of other two groups. To conclude, dominant follicle development/ovulation was not the necessary indication to cancel transfer cycles in HRT cycles, and our cautious decision would save many valuable cycles.     

The benefits of mid-luteal addition of human chorionic gonadotrophin in in-vitro fertilization using a down-regulation protocol and luteal support with progesterone

Luteal support is essential in in-vitro fertilization (IVF)when long-acting gonadotrophin-releasing hormone agonist (GnRHa)is used. Because progesterone lacks luteotrophic stimulation,it seems to be the drug of choice in cases with an increasedrisk of ovarian hyperstimulation syndrome (OHSS). The aim ofthis study was to assess the beneficial effect of the mid-lutealaddition of human choriomc gonadotrophin (HCG) in IVF, usinga down-regulation protocol and luteal support with progesterone,in a prospective randomized study. The study included 170 IVFcycles down-regulated with long-acting GnRHa which were supportedwith 50 mg/day progesterone i.m. during the luteal phase. Patientswere evaluated in the mid-luteal period. Those without clinicalsigns of OHSS, oestradiol concentrations <1000 pg/ml andprogesterone concentrations <50 mg/ml were randomly allocatedto either the addition of 2500 IU HCG (HCG+ group) or no HCG(HCG– group). End luteal phase progesterone concentrationsamong non-pregnant patients were used to assess the contributionof exogenous progesterone and to categorize pregnancies accordingto their corpus luteum function. Similar low OHSS (2.7 and 1.8%)and pregnancy (30 and 29%) rates were observed in the HCG+ andHCG– groups respectively. Of the 26 pregnancies in theHCG+ cases, there was only one case with reduced corpus luteumfunction, compared with 12 of the 25 pregnancies among HCG–patients. Cases with reduced corpus luteum function requiredcontinuous progesterone support and presented lower HCG concentrationsand a higher rate of adverse pregnancy outcome. We concludethat mid-luteal HCG addition does not affect pregnancy rate,but in fact helps to preserve corpus luteum function and avoidsthe need for further supplementation during early pregnancy.     

Assessment of changes in volume and vascularity of the ovaries during the normal menstrual cycle using three-dimensional power Doppler ultrasound

BACKGROUND: Our aim was to describe changes in the volume and vascularization of both ovaries, the dominant follicle and the corpus luteum during the normal menstrual cycle using three-dimensional (3D) power Doppler ultrasound. METHODS: Fourteen healthy volunteers underwent serial transvaginal 3D ultrasound examinations of both ovaries on cycle day 2, 3 or 4, then daily from cycle day 9 until follicular rupture and 1, 2, 5, 7 and 12 days after follicular rupture. The volume and vascular indices of the ovaries, the dominant follicle and the corpus luteum were calculated off-line using virtual organ computer-aided analysis (VOCAL) software. RESULTS: The volume of the dominant ovary increased during the follicular phase, decreased after follicular rupture and then increased again during the luteal phase. Vascular indices in the dominant ovary and the dominant follicle/corpus luteum increased during the follicular phase, the vascular flow index (VFI) in the dominant follicle being on average (median) 1.7 times higher on the day before ovulation than 4 days before ovulation (P=0.003). The vascular indices continued to rise after follicular rupture so that VFI in the corpus luteum was on average (median) 3.1 times higher 7 days after ovulation than in the follicle on the day before ovulation (P=0.0002). The volume and vascular indices in the non-dominant ovary manifested no unequivocal changes during the menstrual cycle. CONCLUSIONS: Substantial changes occur in volume and vascularization of the dominant ovary during the normal menstrual cycle. 3D power Doppler ultrasound may become a useful tool for assessing pathological changes in the ovaries, for example, in subfertile patients.     

Ovary and ovulation: A model conforming the decline in follicle numbers to the age of menopause in women

The store of primordial follicles in the ovary is fixed beforebirth and dwindles with age until it is unable to provide enoughGraafian stages to sustain menstrual cyclicity. According toa simple bi-exponential model of ageing, the rate of follicledisappearance increases at age 37.5 years (or when 25 000 folliclesremain) so that the numbers fall to approximately 1000 at 51years, the median age of menopause in the population. This studyattempts to produce a biologically more realistic model of fofficledisappearance and harmonizes follicle dynamics with the distributionof menopausal ages from an American survey. The step-changein the rate of fofficle attrition was replaced by a model whichassumed that this rate changes more gradually with the sizeof the follicle store. This produced a distribution of predictedmenopausal ages (based on an assumed threshold of 1000 follicles)which was closer to observed data. The fit further improvedwhen the model was modified by having a threshold that variedacross the population. Using such a stochastic threshold modelfor menopause, the number of fertile years remaining could beforecast with an acceptable margin of uncertainty if it everbecomes possible to estimate the size of the follicle storein vivo.     

LHRH agonists in IVF: different methods of utilization and comparison with previous ovulation stimulation treatments

LHRH agonists are being increasingly used in ovulation stimulationprotocols in IVF programmes. We have compared the results oftwo methods of utilization of LHRH agonists. In the long protocol,gonadotrophin stimulation was only commenced after a preliminaryperiod of pituitary desensitization with LHRH agonist. In theshort protocol, exogenous gonadotrophins were administered shortlyafter the start of LHRH agonist therapy, benefitting from thegonadotrophin flare-up effect. One-hundred-and-eighty-six patientswere divided equally between the two treatments. There was nodifference in the ovarian response on the day of HCG or thenumber of mature oocytes recovered. The cleavage rate of matureoocytes was higher in the short protocol (70, versus 56, P<0.01). The ongoing pregnancy rate per treatment cycle was similarin both groups (18, in the long protocol and 16, in the shortprotocol). Analysis of the luteal phases revealed a trend forhigher progesterone values in the long protocol although thiswas only significant on the second day following oocyte retrieval.As the clinical results were similar other factors should betaken into account when deciding therapy. These include patientconvenience, cost and side-effects. Other schedules of ovulationstimulation using LHRH agonists are discussed.     

Ovary and Ovulation: Human follicular nitric oxide pathway: relationship to follicular size, oestradiol concentrations and ovarian blood flow

Nitric oxide (NO) has been suggested to be involved in ovarianphysiology. Our aim was to study follicular nitrite and nitrate(NO₃/NO₂) levels in women undergoing in-vitro fertilization(IVF), and to examine their relationship to follicular size,oestradiol concentrations, and ovarian artery and intra-ovarianblood flow as measured by Doppler ultrasound. A total of 15patients from the IVF programme of Hadassah University Hospital,Mt Scopus, Israel, participated in the study. Detailed transvaginalultrasonographic examination was performed before ovum collection,and ovarian artery and intra-ovarian blood flow were measured.While aspirating the fofficles, the content of two to four ofthe fofficles in each ovary was collected individually, thevolume of follicular fluid measured, and NO₃/NO₂ concentrationswere determined. A statistically significant positive correlationwas found between follicular fluid NO₃/NO₂ concentrations andfollicular volume (r = 0.76), as well as between NO₃/NO₂ concentrationsand oestradiol concentrations (r = 0.63). A statistically significantnegative correlation was found between follicular fluid NO₃/NO₂concentrations and ovarian flow parameters as well as betweenNO₃/NO₂ concentrations in fofficles containing 4–5 mland ovarian artery pulsatility index.