Simplification of the method of in vitro fertilization: sonographic measurements of follicular diameter as the sole index of follicular maturity

Computerized detection and recognition of follicles in ovarian ultrasound images: a review

Observing changes in females' ovaries is essential in obstetrics and gynaecological imaging, e.g., genetic engineering and human reproduction. It is particularly important to monitor the dynamics of ovarian follicles' growth, as only fully mature and grown follicles, i.e., the dominant follicles have a potential to ovulate at the end of a follicular phase. Gynaecologists follow this process in two dimensions, but recently three-dimensional (3-D) ultrasound examinations are coming to the fore. This paper surveys the existing computer methods for detection, recognition, and analyses of follicles in two-dimensional (2-D) and 3-D ovarian ultrasound recordings. Our study focuses on the efficiency, validation, and assessment of proposed follicle processing algorithms. The most important processing steps were identified in order to compare their performances. Higher ranking solutions are suggested for the so-called best algorithm for 2-D and 3-D ultrasound recordings of ovarian follicles. Finally, some guidelines for future research in this field are discussed, in particular for 3-D ultrasound volumes.

Expression pattern of endothelin system components and localization of smooth muscle cells in the human pre-ovulatory follicle

BACKGROUND

Whether ovarian follicular rupture involves contractile activity or not has been debated for decades. Recently, study in the rodents has indicated that an endogenously produced potent vasoconstrictive peptide, endothelin-2 (EDN2), may induce follicular constriction immediately prior to ovulation. This study was aimed to systematically characterize the human ovarian endothelin system and localize smooth muscle cells to assess the possible involvement of contractile activity in human ovulation.

METHODS

This is a prospective experimental study. Study subjects were 20 women aged 20-38 years who underwent IVF owing to tubal or male factors. Expression patterns of messenger RNAs (mRNAs) for EDN1, EDN2, EDN3, endothelin-converting enzyme-1 (ECE1 and ECE2), endothelin receptor A (ET(A)) and ET(B) in the granulosa cells (GCs) and cumulus cells and endothelin peptide concentration in the pre-ovulatory follicles were measured at 36 h after hCG injection. In addition, localization of ovarian smooth muscle cells and endothelin receptor expression were determined in normal (non-IVF patient) ovaries.

RESULTS

Pre-ovulatory follicles express mRNA for EDN1 and EDN2, ECE1, ECE2, ET(A) and ET(B), but not EDN3, contain highly concentrated endothelin peptides (105.9 pg/ml) and are surrounded by theca externa that are made mostly of multicell layer non-vascular smooth muscle cells. ET(A) expression is localized in the smooth muscle cells of theca externa, theca interna and GC, whereas ET(B) expression is confined to theca interna.

CONCLUSIONS

Pre-ovulatory follicles contain highly concentrated endothelins and are surrounded by non-vascular smooth muscle cells that express endothelin receptor, suggesting involvement of endothelin-induced contractile action in ovulation in the human ovary.

Monitoring of in vitro fertilization-embryo transfer cycles by ultrasound versus by ultrasound and hormonal levels: a prospective, multicenter, randomized study

OBJECTIVE

To determine whether cycle monitoring using both serum E(2) and ultrasound findings yields superior clinical pregnancy rates during IVF-embryo transfer (ET) compared to monitoring with ultrasound alone.

DESIGN

Prospective, randomized, multicenter, patient-blinded study.

SETTING

Four assisted conception units in the United Kingdom.

PATIENT(S)

Two hundred ninety-seven women believed to be normal responders undergoing IVF treatment.

INTERVENTION(S)

Patients were randomly allocated on day 7 of stimulation to one of the two hCG administration criteria: [1] the E(2)-to-follicle > or =11 mm ratio was between 250 and 500 pmol/L/follicle and at least 2 follicles reached a mean diameter of 18 mm or [2] at least 2 follicles reached a mean diameter of 18 mm and the endometrium thickness was > or =8 mm.

MAIN OUTCOME MEASURE(S)

Duration and cumulative dose of recombinant human FSH, total number of growing follicles, oocytes retrieved, number and quality of embryos, pregnancy rates, and ovarian hyperstimulation syndrome (OHSS) rates.

RESULT(S)

Two hundred ninety-seven patients were randomized to one of the two criteria groups. Of these, 288 (97%) received urinary (u)-hCG (143 in group A and 145 in group B). One hundred three women in group A (72%) met both criteria for hCG administration. Pregnancy and OHSS rates were similar (34.3% vs. 31.4% and 4.9% vs. 4.1%, respectively).

CONCLUSION(S)

The addition of E(2)/follicle criteria to ultrasound monitoring of IVF cycles in normal responders seldom changes the timing of hCG, and does not increase pregnancy rates or the risk of OHSS.

Can we abandon routine evaluation of serum estradiol levels during controlled ovarian hyperstimulation for assisted reproduction?

OBJECTIVE

To assess whether abandoning measurement of serum estradiol (E2) and spacing ultrasound evaluations at greater intervals had an effect on the results of assisted reproduction technology (ART).

DESIGN

A retrospective comparison of two consecutive periods.

SETTING

Division of Assisted Reproduction Technology, Department of Obstetrics and Gynecology, Ha'Emek Medical Center, Afula, Israel.

PATIENT(S)

One thousand nine hundred and eighty-five controlled ovarian hyperstimulation (COH) cycles for ART were initiated during the years 1996 to 1999.

INTERVENTION(S)

During the first 2 years an intensive follow-up protocol was used that included E2 blood levels measurements. In the next 2 years a less intensive protocol was adopted that did not use E2 measurements.

MAIN OUTCOME MEASURE(S)

ART results and the rate of ovarian hyperstimulation syndrome (OHSS).

RESULT(S)

The patients' background characteristics did not differ between the two periods. The cancellation rate was not different (9.8% vs. 7.2%). There was no difference in the duration of stimulation or the amount of gonadotropins used. The number of oocytes retrieved (12.1 +/- 9.3 vs. 9.6 +/- 6.3), fertilization rates (74% vs. 75%), and clinical pregnancy rates (26.2% vs. 27.9%) did not differ. The incidence of severe ovarian hyperstimulation syndrome was not significantly different between the two periods.

CONCLUSION(S)

Controlled ovarian hyperstimulation for ART can be done reliably without routine, serial serum E2 measurements without compromising the treatment results.

Comparison of follicle steroidogenesis from normal and polycystic ovaries in women undergoing IVF: relationship between steroid concentrations, follicle size, oocyte quality and fecundability

Studies of ovarian stimulation for IVF have suggested a relationship between follicle size and pregnancy rates. Furthermore the follicular endocrine environment is correlated with oocyte quality. The aim of this study was first to verify the relationship between follicular steroid content, follicular size, oocyte maturity and fertilization outcome in women with normal ovaries following recombinant human FSH (rhFSH). Secondly this study was extended to women with polycystic ovarian syndrome (PCOS). Fifty-nine patients (31 normal, 28 PCOS) underwent conventional IVF with rhFSH induction. Follicular diameter was classified as small (8-13 mm) or large (>14 mm) and sex steroid content was analysed for each group. Oocyte maturity was studied according to nuclear maturation the day after fertilization. In both ovulation groups, 17 beta-oestradiol and progesterone concentration were significantly higher in large follicles with meiotically competent oocytes compared with those containing meiotically incompetent oocytes. Testosterone levels were increased in PCOS follicles compared with normal patients, with no difference between corresponding sub-groups of follicles with meiotically competent oocytes. The relationship between follicle size and embryo development showed that 14 mm could be a threshold value following rhFSH induction in normal or PCOS women.

Ultrasound or ultrasound and hormonal determinations for in vitro fertilization monitoring

OBJECTIVE

To compare pregnancy rate, cost effectiveness, patients effort, related stress, and the ovarian hyperstimulation syndrome (OHSS) rate, between patients monitored for ovarian hyperstimulation using a combination of ultrasound and hormonal determination (combination protocol), in contrast to applying ultrasound only, in in vitro fertilization and embryo transfer (IVF ET).

METHOD

This study was carried out on a total of 206 patients who underwent ovarian hyperstimulation with human menopausal gonadotropin and human chorionic gonadotropin (hMG/hCG) protocol. The first 110 patients were monitored every other day by ultrasound only protocol (Group I) while the next 96 patients were monitored daily by a combination protocol (Group II). The pregnancy rate, taking home baby rate, OHSS rate and total cost of monitoring for each patient in both groups were calculated and compared. The patients and the IVF team effort and stress were also compared.

RESULT

Analysis of this study showed no statistical significant differences in clinical pregnancy rate and taking home baby rate between patients in protocol I and II (23.4% vs. 22.9%) and (14.8% vs. 14.3%), respectively. OHSS developed in only two patients--one in each group. The average cost of monitoring was significantly cheaper in Group I--78 Jordanian dinars (JD) vs. 222 JD in Group II (P < 0.0001). (NB: 1 USD = 0.7 JD).

CONCLUSION

Ultrasound monitoring only proved to be cheaper, more convenient and less time consuming for both the patients and the IVF team. However, no significant difference was found regarding the clinical pregnancy rate and taking home baby rate between the two protocols.

Minimal monitoring of ovarian hyperstimulation: a useful simplification of the clinical phase of in vitro fertilization treatment

OBJECTIVE

To investigate the feasibility of IVF treatment with minimal monitoring during ovarian hyperstimulation.

DESIGN

Retrospective analysis and prospective study with real-time control group.

SETTING

Transport IVF program with transport clinic and satellite clinics.

PATIENTS

One hundred consecutive IVF cycles monitored at a transport clinic and 100 concurrent consecutive cycles monitored at satellite clinics, using the same stimulation-monitoring protocol and resulting in oocyte aspiration, are compared retrospectively for the number of ultrasound (US) measurements carried out during monitoring and for results of IVF treatment. No patient selection took place. After introduction of a minimal monitoring protocol at a transport clinic, a prospective study was started comparing 100 minimal monitoring cycles at a transport clinic with 100 concurrent conventional monitoring cycles at satellite clinics, all resulting in oocyte aspiration. Patients entered the retrospective or prospective study only once. In all cases the same laboratory facility was used. Monitoring of ovarian hyperstimulation was done with US measurements only. Cycles were canceled for impending ovarian hyperstimulation syndrome (OHSS) when > 35 follicles were seen to develop during hyperstimulation.

RESULTS

Retrospective analysis shows no difference for the average number of US measurements at transport and satellite clinics (2.8 +/- 0.9 and 3.0 +/- 1.0; mean +/- SD). No differences were found in the number of ongoing pregnancies obtained in the two groups: 22 and 18, respectively. One case of severe OHSS occurred in the satellite clinic group. Introduction of minimal monitoring at the transport clinic gives a significant reduction of the average number of US measurements at the transport clinic compared with satellite clinics, where conventional monitoring continued to be used (1.5 +/- 0.8 versus 2.8 +/- 0.9). Ongoing pregnancies at transport and satellite clinics numbered 33 and 26, respectively. In both groups one patient developed severe OHSS. Sixty-two percent of cycles at the transport clinic were monitored with one US measurement only. No cancellations for impending OHSS occurred during the study period.

CONCLUSION

A large group of patients need only one US measurement during monitoring of ovarian hyperstimulation. Minimal monitoring gives a useful further simplification of the clinical phase of IVF treatment, without adverse effects on treatment outcome and incidence of OHSS.

Vaginal ultrasound in assisted reproduction

Vaginal scanning of the ovaries and the uterus is a diagnostic and monitoring tool of utmost importance in assisted conception. Although the value of ultrasound for monitoring follicular growth has been questioned, few groups working on assisted conception do not use it. Follicle aspiration under the guidance of vaginal sonography is the method of choice. With such a simple and safe technique available, using laparoscopy for retrieving oocytes for assisted conception cannot be justified. The introduction of ultrasound-guided transvaginal retrograde tubal catheterization has meant that laparoscopic GIFT and ZIFT procedures will probably soon be unnecessary. Vaginal sonography is one of the most clinically important diagnostic instruments in assisted conception.

Follicular monitoring and outcome of in vitro fertilization in gonadotropin-releasing hormone-agonist-treated cycles

Previous investigations of in vitro fertilization (IVF) cycles stimulated with gonadotropins have shown that it is possible to predict IVF outcome on the basis of the pattern of estradiol (E2) production in the terminal phase of follicular growth. This analysis looked at endocrine and ultrasound parameters in the late follicular phase of 320 patients in their first cycle of IVF. All cycles were stimulated by an association of gonadotropin-releasing hormone agonists (GnRH-a) and human menopausal gonadotropins (hMG). The pregnancy rate (PR) was not related to the E2 pattern in the 5 days before ovulation induction and was 33% and 39% even when E2 values fell during hMG administration. The PR was independent of the E2 level and the number of follicles greater than 14 mm on the day of human chorionic gonadotropin administration (day 0). The incidence of multiple pregnancy increased when E2 levels were greater than 1,000 pg/mL. It is concluded that follicular phase parameters used for cycle cancellation in hMG-stimulated IVF cycles cannot be extrapolated to GnRH-a/hMG cycles.

Tumors in the lower pelvis as imaged by vaginal sonography

Ultrasound is a sensitive tool for the diagnosis of cystic tumors in the lower pelvis of women. Most knowledge about the ultrasound image of such tumors is based on abdominal scanning. The value of vaginal sonography for evaluation of such tumors has, to the best of our knowledge, so far not been studied. This study was aimed at relating the vaginal sonographic image of tumors in the lower pelvis with the results of macro- and microscopic examination of the tumor. Special interest was paid to establishing ultrasound criteria for classifying unilocular tumors as benign or malignant. One hundred and eighty women who were operated on for pelvic tumors were included in the study. All women were evaluated by vaginal sonography the day before surgery. Ninety-four women were postmenopausal and eighty-six were still menstruating. Vaginal ultrasound characterized the tumor correctly as related to macroscopic examination in 96% (172/180). The sensitivity of vaginal sonography in identifying benign and malignant tumors was 82%, and the specificity, 92%. None of the unilocular tumors was malignant. Papillary formations on the inside of the cyst wall indicated an increased chance of the tumor's being malignant. There was a clear correlation between size of tumor and malignancy except for unilocular tumors. Vaginal sonography was shown to be accurate in characterizing cystic tumors in the lower pelvis. The present results also indicate that the probability that unilocular tumors less than 10 cm in diameter and without papillary formations, are malignant is low, irrespective of the woman's age.

Patients' experience of transvaginal follicle aspiration under local anesthesia

The development of vaginal ultrasound transducers has facilitated ovum pick-up (OPU) by providing higher precision and less trauma than are found with laparoscopy and other ultrasound-assisted techniques. In order to evaluate the patients' acceptance, 65 patients were asked to answer a questionnaire about their experience with the procedure. The punctures were executed with specially designed needles introduced through a needle guide attached to a vaginal transducer with a frequency of 7 MHz (Brüel & Kjaer, Denmark). The anesthesia consisted of a light premedication and a paracervical block. If needed, a small dose of sedative was given intravenously intraoperatively. The patients classified their pain experience within the day of the puncture on a four-grade scale. Their statements were compared to the physician's opinion of the discomfort caused. Oocytes were retrieved from all patients. Fifty-one patients answered the questionnaire, of whom five found the OPU painful. In two cases the physician underestimated the patients' pain experience. The mean time required for the procedure was 16 min/OPU. We conclude that transvaginal ultrasound-guided OPU is well accepted by most patients under local anesthesia and that it is a rapid and accurate procedure.

Spontaneous luteinizing hormone surge and cleavage of in vitro fertilized embryos

The importance of monitoring luteinizing hormone (LH) secretion during gonadotropin stimulation remains controversial. In the present study, the authors evaluated the occurrence of spontaneous LH surges in 170 cycles stimulated by clomiphene citrate and human menopausal gonadotropin, and correlated the success rate of embryo cleavage to the time interval between the occurrence of the LH surge peak value and the time of human chorionic gonadotropin (hCG) administration. LH was quantitated from urine by an avidin-biotin enzyme immunoassay. The results indicated that a spontaneous LH surge occurred in 18% of the cycles. The number of oocytes recovered was not affected by the occurrence of a spontaneous LH surge. In 12% of all cases, the spontaneous LH surge occurred less than 12 hours before the administration of hCG, and in these cases embryo cleavage was not reduced. In 6% of all cases, the spontaneous LH surge occurred over 12 hours before hCG administration, and in these cases embryo cleavage was reduced significantly.

Linear regression analysis of ultrasound follicular growth series: evidence for an abnormality of follicular growth in endometriosis patients

Follicular diameter growth is a highly linear function of time. Recently, the potential utility of linear regression-derived parameters for describing and comparing cycles of follicular growth was described. The linearity of growth, growth rate constant (K), calculated date of growth onset (Do), total growth period (TGP), menstrual age at apparent ovulation (MAov), and peak follicular diameter (PFD) have been calculated from the follicular growth series of a group of patients with laparoscopically diagnosed endometriosis (n = 46). These parameters were compared with those of a group of normal volunteers (n = 18). The authors found significant differences between endometriosis patients and controls in follicular growth rate and total growth period. The effect of patients' clomiphene citrate usage on growth parameters in these patients was examined. Abnormalities in interrelationships between the growth parameters were detected, suggesting the possibility of subtle defects in the regulation of follicular growth in these patients.

Linear regression analysis of ultrasound follicular growth series: statistical relationship of growth rate and calculated date of growth onset to total growth period

Linear regression analysis was used to assess the serial growth of carefully measured individual mean follicular diameters as a function of menstrual age in a group of normal volunteers in natural, unstimulated cycles (n = 18). Follicle diameter (FD) growth, as measured with serial pelvic ultrasonography, can be shown to be essentially linear (mean R2, 0.92) with respect to time up to the point of ovulation. Growth rate (k) and the calculated date of growth onset (Do) are obtainable from the individual regression equations. Because an approximation of the date of ovulation (Dov, measured by menstrual age at the date of peak mean follicular size) is an available parameter, total growth period (TGP) is calculated with the equation (TGP = Dov - Do). Do, k, and TGP are highly correlated with one another. The mean parameters (+/- standard deviation) are Do = 4.29 +/- 2.77 day, k = 0.24 +/- 0.07 cm/day, TGP = 10.32 +/- 2.35 day, peak FD = 2.34 +/- 0.28 cm, and Dov = 14.61 +/- 2.00 day. The internal correlation of these parameters predicts that information from the first several scans in an individual series may be used to forecast date of ovulation. This may represent an improvement over the use of follicle size or menstrual age alone in planning for human chorionic gonadotropin administration, insemination timing, follicular aspiration and other interventions.

Clinical experience in an in vitro fertilization and embryo replacement program of a new method for analysis of urinary estrogens

The clinical experience in an IVF/ER program of a newly developed commercial kit (Estradiol enzymatique; BioMerieux) to determine urinary estrogens enzymatically, is reported. The study included 157 cycles, and the main indication for treatment was infertility due to tubal factor. Follicular development was stimulated in most cases by a combination of clomiphene citrate, human menopausal gonadotropin and chorionic gonadotropin. In addition to the previously used method to monitor follicular growth, ultrasound, daily urinary estrogens (estradiol + estrone) levels were assayed. A correlation between the pattern of urinary estrogen and the clinical results was found. In cycles with continuously rising estrogen up to the time of hCG administration a higher rate of in vitro fertilization and clinical pregnancies were obtained as compared to cycles where urinary estrogen declined or levelled off. It is concluded that this enzymatic assay of urinary estrogens is a good alternative to increase the precision of follicle monitoring when radioimmunological assay of serum estradiol levels cannot be obtained on a daily routine basis.