Assessing ovarian response: antral follicle count versus anti-Müllerian hormone.

Oocyte number and quality decline with age; however, fertility varies significantly even among women of the same age. Various measures have been developed to predict response to ovarian stimulation and reproductive potential. Evaluation of ovarian reserve can identify patients who may experience poor response or hyper-response to exogenous gonadotrophins and can aid in the personalization of treatment to achieve good response and minimize risks. In recent years, two key methods, antral follicle count (AFC), an ultrasound biomarker of follicle number, and the concentration of serum anti-Müllerian hormone (AMH), a hormone biomarker of follicle number, have emerged as preferred methods for assessing ovarian reserve. In this review, a live debate held at the American Society for Reproductive Medicine 2013 Annual Meeting is expanded upon to compare the predictive values, merits, and disadvantages of AFC and AMH level. An ovarian reserve measure without limitations has not yet been discovered, although both AFC and AMH have good predictive value. Published evidence, however, as well as the objectivity and potential standardization of AMH level and the convenience of testing any time throughout the menstrual cycle, leans towards AMH level becoming the gold-standard biomarker to evaluate ovarian reserve and predict ovarian response to stimulation.

A critical review of bi-dimensional and three-dimensional ultrasound techniques to monitor follicle growth: do they help improving IVF outcome?

BACKGROUND: This review focuses on the possibility of improving the outcome of human IVF by studying the follicles where oocytes grow by ultrasound techniques. A comprehensive analysis of bi-dimensional (2D) and three-dimensional (3D) ultrasound (US) assessment of the follicle size and volume is presented. METHODS: Published reports from the year 1999 to 2014 analyzing the relationship between oocyte competence, IVF outcome and ultrasound assessment of the follicle size and volume have been critically analyzed. RESULTS: US assessment of growing follicles has been performed mainly by 2D-US, and while overall very useful, it has been found to be of limited usefulness in predicting oocyte competence, recognize which follicles will release a mature metaphase II oocytes and decide the ideal time to trigger ovulation. In fact, a quite wide follicle size range (16-22 mm) has been reported to be associated with mature oocytes with good competence toward fertilization and embryo development. It has been also shown that smaller follicles sometimes contain mature, fertilizable oocytes. However, embryos derived from smaller follicles have probably a lower implantation potential, while follicles larger than 22 mm often contain post-mature eggs. CONCLUSIONS: The study of follicular size by 2D-US is of limited usefulness in helping in the identification of follicles containing the best oocytes and in choosing the best moment to trigger ovulation. Possibly the value of US in this area will be improved by large prospective studies in which automated 3D-US will be used.

Association between sex steroids, ovarian reserve, and vitamin D levels in healthy nonobese women.

CONTEXT: Vitamin D maintains calcium and phosphorous homeostasis and promotes bone mineralization; however, its nonskeletal functions are increasingly being recognized. Recent evidence supports a role for vitamin D in reproductive potential, but few studies have investigated the potential effects of vitamin D on reproductive hormone biosynthesis and ovarian reserve. OBJECTIVE: The aim of this study was to determine the relationships between the serum level of vitamin D, reproductive hormone levels, and ovarian reserve in healthy nonobese women. DESIGN: This was a cross-sectional study. SETTING: The study was performed at the Fertility Center at CHA Medical Center. PARTICIPANTS: Seventy-three healthy women volunteers participated in this study. The participants were nonobese parous women with regular menstrual cycles and no history of infertility. MAIN OUTCOME MEASURES: We determined serum levels of vitamin D, steroid hormones, SHBG, ovarian reserve markers, homeostatic model assessment of insulin resistance index, and lipid profiles. RESULTS: In linear regression analysis adjusting for age, body mass index, homeostatic model assessment of insulin resistance, and lipid profile, serum vitamin D level positively correlated with total T (P < .001) and free androgen index (P < .001) but did not correlate with dehydroepiandrosterone sulfate or other steroid hormones. The spline regression-suggested relationship between 25-hydroxyvitamin D and total T was most pronounced at a 25-hydroxyvitamin D concentration greater than 13 ng/mL (ß-coefficient 2.374, 95% confidence interval 1.435-3.313). The serum vitamin D level was not associated with the levels of ovarian reserve markers. CONCLUSION: Our study revealed a positive correlation between serum vitamin D level and T level in healthy nonobese women, suggesting that vitamin D may increase fertility through the modulation of androgen activity. The possible causality of the relationship between vitamin D and T deserves further investigation.

Role of ultrasonographic markers of ovarian reserve in prediction of IVF and ICSI outcome.

The aim of the study was to assess correlation of ultrasonographic markers of ovarian reserve and IVF/ICSI outcome. Two-hundred twelve IVF/ICSI patients were included. Upon pituitary suppression confirmation, antral follicle count (AFC), ovarian volume (OV), and ovarian stromal indices [vascularization index (VI), flow index (FI), and vascularization flow index (VFI)] were assessed by three-dimensional (3D) and power Doppler (PD) ultrasound and correlated with the number of mature oocytes retrieved. The number of mature oocytes retrieved correlated strongly with AFC (r = 0.832, p ≤ 0.001) and OV (r = 0.835, p ≤ 0.001), but weakly with VI (r = 0.166, p = 0.016), FI (r = 0.151, p = 0.028), and VFI (r = 0.14, p = 0.041). AFC and OV correlate strongly with the number of mature oocytes retrieved in IVF/ICSI cycles, whereas 3D PD indices of the ovarian stromal vascularity have a weak correlation.

Predictive value of antral follicle count and anti-Müllerian hormone for follicle and oocyte developmental competence during the early prepubertal period in a sheep model.

Circulating anti-Müllerian hormone (AMH) and antral follicle count (AFC) are addressed as suitable markers of oocyte quantity and quality during adulthood. To investigate whether AFC and circulating AMH could predict follicle development and oocyte quality during the prepubertal period we used 40-day-old ewe lambs with high, intermediate and low AFC (≥30, 16-29 and≤15 follicles respectively). The analysis of the response to the exogenous FSH ovarian reserve test showed a positive correlation between AFC, AMH plasma levels, total follicle number and the number of large follicles (≥3mm) grown after exogenous FSH administration. The incorporation of abattoir-derived oocytes collected from ovaries with different AFC in an in vitro embryo production system showed that a high AFC can predict oocyte quality in prepubertal ovaries, reflecting an ovarian status suitable for follicular development. The histological quantification of the ovarian reserve evidenced that AFC was not predictive of differences in either the number of healthy follicles or the size of the primordial follicle pool in prepubertal ovaries. Further studies are needed to investigate the implication on the reproductive performance of the significant inter-individual differences found in the present study in AFC and circulating AMH in the early prepubertal period.

Ultrasound biomicroscopy: a non-invasive approach for in vivo evaluation of oocytes and small antral follicles in mammals.

The use of ultrasonography has changed our understanding of the ovarian function in live animals. However, most of the studies that have used ultrasonography to image the ovary have provided data only of structures >1mm in diameter. The recent availability of high-resolution ultrasound technology with high-frequency transducers (25-70 MHz), offers the potential to examine the developmental dynamics of small antral follicles and the cumulus-oocyte complex (COC) in vivo. In this review we provide data from a series of studies performed by Veterinary Biomedical Sciences Laboratory describing the advantages and disadvantages, as well as image characteristics, of ultrasound biomicroscopy (UBM) to study ovarian biology in mammals. Data and images of small ovarian structures in rabbits, cattle, mice and humans are shown. The UBM technique allowed visualisation of small antral follicles ranging in size from 300 to 700 µm in all species examined, as well as COC within follicles in rabbits, cattle and humans. Furthermore, UBM permitted clear distinction of the follicular wall from the surrounding ovarian stroma in cattle and humans. At present, the limited depth of penetration of UBM restricts the use of this technique to an experimental setting. In that regard, further studies using UBM will probably result in a greater understanding of the pattern and control of early antral folliculogenesis and oogenesis.

Unfavorable lipid profile and higher frequency of hot flashes during perimenopausal years after fallopian tube ligation.

AIM: We sought to study the effect of tubal ligation on lipid profile, ovarian reserve and hot flashes during perimenopausal years. METHODS: A total of 210 perimenopausal women complaining of abnormal vaginal bleeding were enrolled for the study. Subjects' menstrual, reproductive and medical histories were recorded. Serum FSH, LH and estradiol levels were screened in all women to determine menopausal status. In order to rule out any gynecologic pathology, all subjects underwent transvaginal sonography. Women were divided into two groups according to presence (study group, n = 68) or absence (control group, n = 142) of tubal ligation history. Lipid profiles and ovarian reserve tests were compared between groups. RESULTS: Mean age, parity, serum hemoglobin (Hb), high density lipoprotein (HDL-C), triglyceride, estradiol levels, endometrial thickness and frequency of hot flashes were significantly different between groups (p < 0.05). Mean age was 42.8 ± 1.9 years in women with tubal ligation and 45.9 ± 3.5 years in control group. Mean serum estradiol level was lower in group with tubal ligation (41.4 versus 92.5 pg/ml). Mean endometrial thickness was higher in control group (10.2 versus 7.5 mm). Age-adjusted serum Hb, HDL-C, triglyceride, estradiol, FSH level, endometrial thickness and frequency of hot flashes remained significantly different between groups (p < 0.05). CONCLUSION: Tubal ligation is associated with unfavorable lipid profile and higher frequency of hot flashes during perimenopausal years.

Changes of endocrine and ultrasound markers as ovarian aging in modifying the Stages of Reproductive Aging Workshop (STRAW) staging system with subclassification of mid reproductive age stage.

OBJECTIVE: To demonstrate the changes of ovarian aging markers across the Stages of Reproductive Aging Workshop (STRAW) stages and modify it with subclassification of mid reproductive age stage (MR). DESIGN: Healthy females were classified according to the STRAW system. Serum basal FSH, LH, E2, and anti-Müllerian hormone (AMH) were detected, FSH/LH ratio calculated, and antral follicle counts (AFCs) determined in follicular phase. RESULTS: Progression through the whole STRAW stages under MR stage subdivided is associated with elevations in FSH, LH, FSH/LH ratio and decreases in E2, AMH and AFCs (p < 0.001). Both serum AMH and AFCs decreased early (after 25 years) and significantly (p < 0.01) with chronological age in MR stage. 0.982 ng/ml AMH and 3 antral follicles (low level of MR 25-30 years) were set as cutoffs to distinguish MR stage into early mid reproductive age (EMR) and late mid reproductive age (LMR) stages. The women in EMR stage compared with LMR could retrieve more oocytes in IVF treatment (p < 0.05) and has a higher pregnancy chance (57.9%) though not significant. CONCLUSION(S): The early and marked fall in serum AMH levels and AFCs suggest fine markers to further categorize and define the MR stage, demonstrating disparate reproductive aging period with reduced ovarian reserve in young age across the STRAW stages.

In vivo imaging of cumulus-oocyte-complexes and small ovarian follicles in cattle using ultrasonic biomicroscopy.

The objectives of this study were to: (1) evaluate the feasibility of ultrasonic biomicroscopy (UBM) for imaging ovarian follicles in vivo in cows and heifers, (2) compare the transvaginal to the transrectal approach, (3) compare the number of follicles detected by UBM to conventional ultrasonography (US), and (4) identify cumulus-oocyte-complexes (COC) within follicles by UBM. Mature cows (n=5) and peri-pubertal heifers (n=5) were examined once using conventional B-mode US (Aloka 900) with a 7.5 MHz transrectal, and a 5 MHz transvaginal transducers. A second series of examinations was performed using UBM (Visualsonics Vevo 660) equipped with a 30 MHz transrectal and a 40 MHz transvaginal transducer. A three- to four-fold increase in the number of small follicles (<3 mm) was detected using the transvaginal approach with UBM compared to conventional US in both heifers (32.4 ± 4.24 compared to 7.2 ± 1.4; P<0.0001) and cows (35.0 ± 13.8 compared to 10.7 ± 7.5; P=0.0013). However, fewer follicles (all sizes combined) were detected using the transrectal approach with UBM compared to conventional US in both heifers (8.6 ± 5.6 compared to 17.6 ± 4.9; P=0.02) and cows (5.3 ± 6.1 compared to 20.3 ± 7; P=0.04). In heifers, COC-like structures were identified in 39 of 202 (19.3%) follicles examined. In conclusion, UBM using a transvaginal approach is feasible and may be used for in vivo assessment of early antral follicles as small as 0.4 mm, and COC within follicles.

Abnormal expression of growth differentiation factor 9 and bone morphogenetic protein 15 in stimulated oocytes during maturation from women with polycystic ovary syndrome.

OBJECTIVE: To investigate the expression pattern of two oocyte-secreted factors-growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BM15)-during oocyte maturation in women with polycystic ovary syndrome (PCOS) and in controls and to evaluate the expression differences in oocytes between the two groups. DESIGN: Case-control study. SETTING: University-affiliated hospital. PATIENT(S): Twenty-five oocytes were obtained from 12 patients with PCOS and 82 oocytes from 56 controls. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The abundance of GDF9 and BMP15 mRNA in oocytes of the germinal vesicle (GV), metaphase I (MI), and MII stage. RESULT(S): The expression of GDF9 and BMP15 mRNA displayed dynamic changes during oocyte maturation in controls after ovarian stimulation, with a decline at the MI stage and an increase to the peak at the MII stage. However, their expression in oocytes from patients with PCOS demonstrated a reduced state without any dynamic change. CONCLUSION(S): The results suggest that the expression of GDF9 and BMP15 in oocytes from patients with PCOS cannot reach the normal level even after ovarian stimulation and that the expression pattern is abnormal during oocyte maturation, which may be associated with impaired oocyte quality and developmental competence in PCOS.

Developmental competence of antral follicles and their oocytes after gonadotrophin treatment of sows with gene polymorphisms for leptin and melanocortin receptors (Iberian pig).

PURPOSE: To evaluate possible differences in follicle and oocyte developmental competence after gonadotrophin treatment in sows of obese and lean genotypes. METHODS: Follicle dynamics, ovulation rate and oocyte developmental competence to embryo were compared between females, of obese (n = 7) and lean genotypes (n = 10), treated with 1,250 I.U. of eCG and 500 I.U. of hCG. RESULTS: The obese genotype showed lower numbers of follicles growing to preovulatory stages (12.4 ± 1.8 vs 18.6 ± 1.0, P < 0.05), of corpora lutea (16.0 ± 0.9 vs 23.5 ± 0.9, P < 0.05), and of recovered oocytes/embryos (8.0 ± 1.3 vs 12.9 ± 0.9, P < 0.05). Thereafter, embryo viability rates also decreased when compared to lean genotypes (62.5 vs 77.6%, P < 0.05). DISCUSSION: To our knowledge, this is the first study analyzing the effect of obese genotypes on the ovarian response to exogenous gonadotrophins in a non-rodent animal model, the pig. A lower efficiency of gonadotrophin treatments for stimulation of follicle development and induction of ovulation was observed.

[Ovarian reserve]. / Réserve ovarienne.

Ovarian reserve assessment has become critical when counselling infertile couples. This evaluation should be conducted in all women over 35 years, or earlier in case of familial history of premature ovarian failure, gonadotoxic treatment of short menstrual cycles. The first step for ovarian reserve assessment is to measure basal hormonal status, i.e. day 3 FSH and estradiol. If necessary, antral follicle count performed by a skilled operator and/or serum AMH level can give some relevant additional information. The historical concept of 2-years waiting does not make sense any more regarding the current delay in childbearing. Therefore, the infertility workup, and particularly ovarian reserve assessment, should be initiated after 6 months of infertility in all women over 35 years of age.

Ovarian hyperstimulation syndrome prevention strategies: in vitro maturation.

The only reliable way to eliminate the risk of ovarian hyperstimulation syndrome (OHSS) is complete avoidance of gonadotropin ovarian stimulation. It could be argued that in vitro maturation (IVM) of oocytes represents the most effective strategy to prevent OHSS. IVM has been an established treatment option in many centers worldwide for over a decade. The use of IVM and natural cycle in vitro fertilization (IVF) combined with IVM can result in clinical pregnancy rates that compare to those obtained with conventional IVF. The obstetric and perinatal outcomes of IVM pregnancies are similar to those conceived from stimulated IVF or spontaneous conceptions. To date, more than a thousand healthy infants have been born without an increase in fetal abnormalities. Although IVM may not replace standard IVF, it plays an increasingly important role in assisted reproductive technology, especially in the settings of high responders and those patients at risk of OHSS.

Ultrasonographic-guided retrieval of cumulus oocyte complexes after super-stimulation in dromedary camel (Camelus dromedarius).

In Experiment 1, studies were conducted to apply the transvaginal ultrasound guided ovum pick-up (OPU) technique in dromedary camels after their ovarian super-stimulation and in vivo oocyte maturation. In Experiment 2, the developmental potential of two commonly used oocyte types, i.e., in vivo matured oocytes collected by OPU and abattoir derived in vitro-matured oocytes was compared after their chemical activation. In Experiment 3, developmental competence of oocytes collected from super-stimulated camels by OPU, matured either in vivo or in vitro, was compared after their chemical activation. Mature female dromedary camels super-stimulated with a combination of eCG and pFSH were given an injection of 20 microg of the GnRH analogue, buserelin 24, 26, or 28 h before the scheduled OPU. For collection of cumulus oocyte complexes (COCs) the transducer was guided through the vulva into the cranial most portion of the vagina and 17-gauge, 55 cm single-lumen needle was placed in the needle guide of the ultrasound probe and advanced through the vaginal fornix and into the follicle. Follicular fluid was aspirated using a regulated vacuum pump into tubes containing embryo-flushing media. Aspirates were searched for COCs using a stereomicroscope, and they were then denuded of cumulus cells by hyaluronidase and repeated pipetting. The oocytes were classified as mature (with a visible polar body), immature (with no visible polar body), activated (with divided or fragmented ooplasm) and others (degenerated and abnormal). Overall an average of 12.12 +/- 7.9 COCs were aspirated per animal with an oocyte recovery rate from the aspirated follicles of about 77%. The majority (> 90%) of the collected COCs by OPU were with loose and expanded cumulus cells. The proportion of matured oocytes obtained at 28-29 h (91.2 +/- 4.1) and 26-27 h (82.1 +/- 3.4) were higher (P < 0.005) when compared with those obtained at 24-25 h (40.4 +/- 16.3) after GnRH administration. In Experiment 2, a higher proportion (P < 0.05) of in vivo matured oocytes cleaved (84.6 +/- 2.1 vs. 60.9 +/- 6.6) and developed to blastocyst stages (52.4 +/- 4.1 vs. 30.5 +/- 3.3) when compared with in vitro matured oocytes collected from slaughterhouse ovaries. In Experiment 3, no difference was observed between the developmental competences of oocytes, collected from super stimulated camels, matured in vitro with those collected after their in vivo maturation. In conclusion, about 80-90% mature oocytes can be collected by ultrasound guided transvaginal ovum pick-up from super-stimulated dromedary camels 26-28 h after GnRH administration. The developmental response, to chemical activation, of in vivo matured oocytes collected by ultrasound guided transvaginal OPU is better than in vitro matured oocytes obtained from slaughterhouse ovaries. However, no difference was observed in the developmental competence of oocytes collected by OPU whether they were matured in vivo or in vitro.

A method to improve false interpretation of the endometrial echo pattern as homogeneous hyperechogenic.

Endometrial echo patterns are generally evaluated and graded via transvaginal sonography; however, the uterine position can impede adequate visualization, giving the false impression of a hyperechogenic echo pattern before ovulation or oocyte retrieval. Transabdominal sonography can eliminate this error in the majority of cases when transvaginal ultrasound fails to provide diagnostic images of the endometrium.

Clinical outcomes for various causes of infertility with natural-cycle in vitro fertilization combined with in vitro maturation of immature oocytes.

The clinical outcomes of different infertility causes (tubal factor, male factor, unexplained infertility, combination of tubal and male factors, and other/mixed factors) with natural-cycle in vitro fertilization/maturation (IVF/M) treatment were evaluated. There were no significant differences in the rates of IVM, IVF, and cleavage as well as the clinical pregnancy (30.4%-46.9%) and live birth rates among the five subgroups, which suggests that natural-cycle IVF/M is a suitable treatment for infertility of various causes with acceptable pregnancy and live birth rates.

Timing of oocyte maturation and egg collection during controlled ovarian stimulation: a randomized controlled trial evaluating manual and automated measurements of follicle diameter.

OBJECTIVE: To evaluate the effect of a new automated technique of follicle measurement (Sono automated volume calculation [SonoAVC]) on the timing of oocyte maturation and subsequent oocyte retrieval. DESIGN: Prospective randomized controlled trial. SETTING: University-based Assisted Conception Unit. PATIENT(S): Seventy-two women undergoing their first cycle of assisted reproduction treatment. INTERVENTION(S): The timing of final follicle maturation and oocyte retrieval based on follicle tracking with use of either conventional two-dimensional (2D) ultrasound or SonoAVC. MAIN OUTCOME MEASURE(S): The number of mature oocytes retrieved and clinical pregnancy rate. RESULT(S): The number of the mature oocytes collected (10.70 +/- 6.08 vs. 11.43 +/- 6.17), the number of fertilized oocytes (7.27 +/- 4.78 vs. 7.97 +/- 5.25), and the clinical pregnancy rates (42% vs. 43%) were similar with both 2D ultrasound and SonoAVC methods. CONCLUSION(S): Automated follicle tracking using SonoAVC identifies a comparable number of follicles to real-time 2D ultrasound in this preliminary study. Timing final follicle maturation and egg retrieval on the basis of these automated measures does not appear to improve the clinical outcome of assisted reproduction treatment.

The impact on ovarian reserve after laparoscopic ovarian cystectomy versus three-stage management in patients with endometriomas: a prospective randomized study.

OBJECTIVE: To investigate the effect of two different laparoscopic methods on ovarian reserve in patients with ovarian endometriomas. DESIGN: Prospective, randomized clinical trial. SETTING: Endoscopy unit of a university hospital. PATIENT(S): Twenty women with endometriomas. INTERVENTION(S): Patients were randomly selected to undergo either laparoscopic cystectomy for endometrioma (group 1) or the "three-step procedure" (group 2). Before and 6 months after laparoscopy all patients were evaluated, and 12 months postoperatively they underwent ultrasound scan examination. MAIN OUTCOME MEASURE(S): The primary end point was ovarian reserve damage based on the alterations of anti-Müllerian hormone (AMH). Secondary end points were the changes of antral follicle count and serum concentration of FSH, LH, E(2), and inhibin B. RESULT(S): Mean serum AMH was reduced significantly from 3.9-2.9 ng/mL in group 1 compared with the reduction from 4.5-3.99 ng/mL in group 2. CONCLUSION(S): Ovarian reserve determined by AMH is less diminished after the three-step procedure compared with cystectomy of endometriomas.

True ovarian volume is underestimated by two-dimensional transvaginal ultrasound measurement.

OBJECTIVE: To investigate a possible difference between true ovarian volume and ovarian volume estimated with two-dimensional (2D) transvaginal ultrasound. DESIGN: Prospective clinical and laboratory study. SETTING: University hospital research laboratory. PATIENT(S): Premenopausal girls and women from three Danish national fertility centers (A: n = 42; B: n = 6; C: n = 18), who had one entire ovary removed for cryopreservation of ovarian cortex. INTERVENTION(S): Transvaginal 2D ultrasound measurement of ovarian volume before oophorectomy. True ovarian volume was obtained by weighing the ovary. MAIN OUTCOME MEASURE(S): Ovarian volume estimated by weight and ultrasound. RESULT(S): Ovarian tissue density was 1.00 g/mL. Mean ovarian volume by ultrasound vs. weight in the three groups was as follows: A: 6.3 mL vs. 7.8 mL; B: 5.4 mL vs. 6.8 mL; and C: 2.8 mL vs. 6.1 ml. Ovarian volume obtained by ultrasound was at least 27% smaller than the true ovarian volume. CONCLUSION(S): Ovarian volume was severely underestimated by transvaginal 2D ultrasound measurement.

Prospective cohort study of three- versus two-dimensional ultrasound for prediction of oocyte maturity.

OBJECTIVE: To determine whether three-dimensional follicular ultrasound (3-D) measurements are better predictors of optimal timing of hCG administration than two-dimensional (2-D) images, the current standard. DESIGN: Prospective, cohort study. SETTING: Tertiary referral center. PATIENT(S): Seventy-six patients undergoing IVF. INTERVENTION(S): Seventy-six consecutive patients undergoing serial follicular monitoring during IVF had an additional daily 3-D volume scan of their ovaries once lead follicles had reached 16 mm diameter. MAIN OUTCOME MEASURE(S): Number of mature oocytes retrieved. RESULT(S): The 2-D follicular diameter measurements predicted 25.4% of the observed variance in the number of mature oocytes retrieved. The 3-D follicular volume measurements were more predictive of outcome, accounting for 29.2% of the observed variance in number of mature oocytes retrieved. Follicles >22 mm diameter and 5 mL volume were associated with fewer mature oocytes reflecting an undesired postmature state. Follicles measuring 11 to 15 mm had a 50% chance of yielding a mature oocyte. CONCLUSION(S): Three-dimensional follicular volume measurements have a stronger correlation with the number of mature oocytes retrieved than 2-D measurements. As 3-D technology improves, this parameter may replace 2-D measurements in the optimal timing of hCG before oocyte retrieval.