Paraoxonase 1 (PON1) attenuates sperm hyperactivity and spontaneous acrosome reaction.

BACKGROUND: Sperm capacitation is essential for proper fertilization and is associated with increased sperm hyperactivity (HA) and acrosome reaction (AR). For successful fertilization, AR timing is critical; accordingly, early spontaneous AR may not facilitate fertilization. Paraoxonase 1 (PON1) possesses antioxidant properties which affect sperm capacitation. The association between PON1, semen parameters, and capacitation is not fully understood. OBJECTIVE: To study PON1 activity in relation to human sperm hyperactivity and AR. MATERIALS AND METHODS: Semen samples were collected, and parameters were determined (volume, concentration, total sperm count, percentage total motility, and percentage normal morphology) according to World Health Organization (WHO) guidelines. AR and hyperactivity were evaluated using FITC-PSA, staining, and computer-aided sperm analysis (CASA). PON1 activity was assessed using arylesterase activity assay. RESULTS: Purified PON1 inhibited both sperm hyperactivity and AR in a dose-dependent manner. Native semen PON1 activity was positively associated with higher sperm concentration and negatively associated with spontaneous acrosome reaction (sAR). DISCUSSION AND CONCLUSION: PON1 may have a positive effect on fertility via its ability to prevent early spontaneous sperm capacitation and AR before reaching the female genital tract.

Successful use of the Cryolock device for cryopreservation of scarce human ejaculate and testicular spermatozoa.

The existing methods for cryopreservation of very low count sperm samples are complex and sub-optimal for individual spermatozoa. Our purpose is to establish an effective simple method for cryoprotecting individual spermatozoa. Samples from patients with OTA were mixed with TYB or HEPES-buffered salt solution with glycerol + glucose and placed on a Cryolock that was plunged directly into liquid nitrogen or exposed to its vapors. Thawing was performed by direct immersion into a drop of warmed medium. The favorable method was tested on diluted samples (10-50 cells) and leftover TESE specimens from patients with azoospermia. Cryopreservation was considered successful if >30 spermatozoa, (>3 motile), or >5 spermatozoa (>1 motile) in diluted and TESE samples, were detected post-thawing. A significantly higher survival rate of seminal spermatozoa was obtained when using the Cryolock with TYB and freezing with liquid nitrogen vapor, compared to HEPES glycerol-glucose (95 vs. 35% respectively). Plunging the Cryolock into liquid nitrogen was detrimental. Cryolock combined with TYB cryoprotection and liquid nitrogen vapor freezing was highly effective for cryopreservation of individual spermatozoa in diluted and TESE samples. The Cryolock may serve for freezing very low-count sperm samples and individual spermatozoa. This method offers simplicity, efficacy, use of available materials, without requiring micromanipulation equipment or skills.

Platelet-derived growth factors (PDGF-A and -B) and their receptors in human fetal and adult ovaries.

There is no information regarding the presence of platelet-derived growth factors (PDGFs) and their receptors in human ovaries. The expression of PDGF-A, -B and their two receptors, PDGFR-alpha and -beta, was investigated in ovarian samples from women/girls and from human fetuses, at the protein and mRNA levels. The samples were prepared for immunohistochemical staining for PDGF-A and -B and their two receptors and in situ hybridization for the detection of the mRNA transcripts of the receptors. Total RNA was extracted from frozen ovarian samples, and the expression of PDGF-A and -B was investigated by reverse transcription-polymerase chain reaction. The proteins for PDGF-A and -B were detected in oocytes, and in granulosa cells (GC) of 50% of the follicles from women/girls. The proteins and mRNA transcripts for the two receptors were detected in oocytes (mRNA for PDGFR-beta only in 25% of the oocytes). PDGFR-alpha mRNA was expressed in GC of a minority of the samples from women/girls, whereas PDGFR-beta protein and mRNA were identified in over 50% of the GC from this source. PDGF-A and -B transcripts were identified in all the extracts. The presence of the receptors in GC suggests that PDGFs might be involved in the activation of primordial follicles.

Is assisted hatching beneficial in patients with recurrent implantation failures?

PURPOSE: To assess the possible role of assisted hatching in patients with recurrent implantation failure during IVF cycles. DESIGN: Prospective randomized study. SETTING: IVF unit of an academic medical center. PATIENTS: Women who underwent IVF after at least three failed IVF-ET attempts. INTERVENTIONS: Patients were prospectively randomized to undergo assisted hatching of their embryos prior to their replacement by mechanical partial zona dissection. RESULTS: The study (assisted hatching) and control groups included 104 and 103 patients, respectively. There were no significant between-group differences in patient age, cause of infertility, mean number of previous IVF trials, number of oocytes retrieved, fertilization rate, or number of embryos transferred. No difference in pregnancy rate was noted on comparison of the whole study group, to the whole control group (21% and 27%, respectively). However, when the results were re-analyzed by age groups, assisted hatching was found to be harmful in the youngest group (< 34 years), significantly decreasing pregnancy rates (15% vs 35%, p < 0.05). CONCLUSION: Repeated implantation failure alone is not an indication for assisted hatching. Although assisted hatching appears to be effective in a selected group of older patients, in younger patients it may further hamper implantation and should be avoided.

Inclusion of standard and low-dose gonadotropin releasing hormone-analog (short protocol) in controlled ovarian hyperstimulation regimens in normogonadotropic patients aged 40-48 years who are undergoing in vitro fertilization.

We aimed to compare the efficiency of three controlled ovarian hyperstimulation protocols in achieving superovulation in normogonadotropic patients aged 40 years or more, who were undergoing in vitro fertilization (IVF) treatment. This was a prospective randomized clinical study, carried out in the Infertility and IVF Unit of an academic tertiary hospital. A total of 219 normogonadotropic patients (serum follicular stimulating hormone level < 15 mIU/ml) aged 40-48 years, with regular menstrual cycles, were randomly allocated to one of three short follicular protocols: menotropins only (group A), menotropins plus a mini-dose of gonadotropin releasing hormone (GnRH)-analog (600 microg/ day) (group B), or menotropins plus a standard dose (900 microg/day) of a GnRH-analog (group C). Those cycles that reached the stage of oocyte retrieval (67, 70 and 71 cycles, respectively) were analyzed. The mean daily dose of menotropins needed for ovarian stimulation was higher when GnRH-analog was used (groups B and C) (p < 0.02; ANOVA), although there was no significant difference in the time of human chorionic gonadotropin injection (average: cycle day 11). Peak estradiol levels (p < 0.02), number of oocytes retrieved (3.9, 5.4 and 5.5 oocytes/cycle, respectively, p < 0.02) and number of embryos transferred (1.6, 1.8 and 2.1 embryos/cycle, respectively, p < 0.05) were higher when GnRH-analog was included in the controlled ovarian hyperstimulation protocol. The IVF treatment resulted in 19 pregnancies (9.1% implantation rate), with a similar distribution among all three groups (11.9%, 8.6% and 7.0%). However, a higher miscarriage rate was noted in the menotropins-only group (67.5% vs. 33.3% and 40.0% of pregnancies). No differences were observed in any of the aforementioned variables between the mini-dose and standard dose GnRH-analog groups (groups B and C). In conclusion, controlled ovarian hyperstimulation before IVF treatment in normogonadotropic patients aged 40 years or more is more effective when a GnRH-analog (short protocol) is included in the treatment regimen. In this selected group of patients, reducing the daily dose of GnRH-analog does not improve the treatment results.

Gonadotropin stimulation following GnRH-a priming for poor responders in in vitro fertilization-embryo transfer programs.

The effect of gonadotropin-releasing hormone agonist (GnRH-a) administration before gonadotropin superovulation on the stimulation characteristics of poor responder patients was assessed in an in vitro fertilization (IVF) program. Thirty consecutive patients who had exhibited low ovarian response (fewer than four retrieved oocytes) in at least two previous IVF cycles (control cycles, n = 60), were eligible for the study. GnRH-a (nafarelin) was administered daily for 7-10 days from the mid-luteal phase of the previous cycle until the first day of menstruation. Menotropin treatment was commenced on cycle day 3 (with no additional GnRH-a) (study cycles, n = 39). A significantly higher number of oocytes was retrieved (p < 0.0002) and a higher number of embryos transferred (p < 0.003) in the study cycles than in the control cycles. No cases of premature luteinizing hormone surge were recorded. Pregnancy rates per embryo transfer and per cycle were 10.4% and 7.7% for the study cycles and 2.8% and 1.6% for the control cycles, respectively. GnRH-a, administered prior to gonadotropin treatment, should be an additional option of ovulation induction protocol for poor responders in IVF programs.

Doppler parameters of uterine and ovarian stromal blood flow in women with polycystic ovary syndrome and normally ovulating women undergoing controlled ovarian stimulation.

OBJECTIVE: To test the hypothesis that the increased ovarian sensitivity to gonadotropins observed in women with polycystic ovary syndrome (PCOS) may be due to changes in ovarian stromal blood flow in these patients. DESIGN: Uterine and ovarian stromal arterial blood flow (with transvaginal color Doppler ultrasound) were measured in ten women with PCOS and 12 normo-ovulatory women (control group), undergoing gonadotropin stimulation before in vitro fertilization. METHODS: A careful ovarian stimulation strategy was adopted for the study group in order to avoid ovarian hyperstimulation syndrome and achieve an ovarian response which was comparable to that of the control group. Resistance and pulsatility indices (RI and PI) of the uterine and ovarian stromal arteries were calculated before the onset of gonadotropin treatment, on cycle day 5 (after commencing treatment), day of human chorionic gonadotropin injection, day of ovum pick-up as well as on the day of embryo transfer, and 7 and 12 days later. RESULTS: No significant differences were found in RI and PI between the study and control groups throughout the treatment cycle. CONCLUSIONS: It seems that polycystic ovaries do not bear an inherent disturbance in blood flow dynamics of the uterine and ovarian arteries, as measured by color Doppler, which would explain the increased sensitivity of polycystic ovaries to stimulation with gonadotropins.

Treatment variables in relation to oocyte maturation: lessons from a clinical micromanipulation-assisted in vitro fertilization program.

OBJECTIVE: In an effort to understand the mechanism underlying the improved pregnancy rate observed in IVF cycles when gonadotropin-releasing hormone analogues (GnRH-a) are applied, we investigated a possible relationship between treatment variables and oocyte nuclear maturity. DESIGN: Nuclear maturity was retrospectively assessed in cumulus-free, denuded oocytes, obtained from women undergoing micromanipulation-assisted IVF treatment following controlled ovarian hyperstimulation with GnRH-a and menotropins. SETTING: The setting was the infertility and IVF unit of a tertiary academic medical center. PARTICIPANTS: Two hundred twenty-one patients underwent 435 treatment cycles. MAIN OUTCOME MEASURE: This was the proportion of germinal vesicle-intact immature (GVII) oocytes. RESULTS: One hundred fifty-four of the 3520 oocytes studied (4.4%) were in the GVII stage. These oocytes were found in 66 of the treatment cycles (15.2%) and in 54 of the patients (24.4%). Cycles in which GVII oocytes were detected did not differ from those in which all the aspirated oocytes were mature in the following respects: patient age, type and duration of infertility, controlled ovarian hyperstimulation protocol and time of ovum pickup. However, the GVII group was characterized by a significantly higher peak estradiol level, as well as a higher number of mature follicles visualized sonographically (diameter, > 14 mm) and oocytes retrieved. CONCLUSIONS: Comparing the present findings with previously published data, it appears that the inclusion of GnRH-a in the stimulation regimen is associated with a lower proportion of immature oocytes. A higher occurrence of oocyte-nuclear immaturity is apparently associated with a significantly better ovarian response to stimulation. The high incidence of immature oocytes observed in patients with normospermic partners and low fertilization rates in previous cycles may suggest that the fertilization failure in some of these cases is due to oocyte, rather than sperm, dysfunction.

Neonatal assessment of babies conceived by in vitro fertilization.

PROBLEM: Neonatal outcome of in vitro fertilization (IVF) pregnancies has been described by different authors, but several issues have yet to be resolved. The aim of the present study was to evaluate neonates conceived in vitro and to direct special attention to neonatal morbidity and prevalence of minor abnormalities. The information that has been accumulated so far is scant. METHOD: The first 100 babies conceived in vitro, and subsequently born in our institute, were investigated and compared with the general, spontaneously conceived newborn population. All infants were examined by a senior neonatologist, and the data that were recorded included gestational age at delivery, birth weight, gender, major malformations, minor congenital abnormalities, neonatal mortality, and neonatal morbidity (including asphyxia, jaundice, meconium aspiration, hypoglycemia, and hypocalcemia). RESULTS AND CONCLUSIONS: The data indicate that the IVF neonates assessed had a higher rate of low birth weight (37%), twinning (30%), and preterm birth (20%) in comparison with the general reference population (p < 0.05). However, no differences were encountered either in the rate of small for gestational age infants or the incidence of major malformations and minor abnormalities between these groups of newborns. The overall neonatal morbidity in IVF babies was found to exceed that of the general population. Nevertheless, at birth, there were no clinical pathognomonic signs typical of IVF babies, although more detailed metabolic, endocrine, and neurobehavioral studies are still required to confirm that newborns conceived in vitro do not differ from those conceived spontaneously in any of these respects.

Augmentation of low ovarian response to superovulation before in vitro fertilization following priming with contraceptive pills.

Poor ovarian response to superovulation treatment is observed in a certain group of patients, the so-called 'low responders'. Despite the evolution of sophisticated controlled ovarian hyperstimulation (COH) regimens prior to the in vitro fertilization (IVF), the ideal stimulation protocol for the low responder has yet to be formulated. The objective of this study was to assess the effect of oral contraceptive pills (OCP), administered before the initiation of superovulation, on ovarian response and IVF treatment results in patients with previous 'low response' to exogenous gonadotropin stimulation. The study group comprised 42 patients who had exhibited poor ovarian response to standard superovulation protocols in at least two previous consecutive treatment attempts. Contraceptive pills were administered for 28-42 days and were immediately followed by menotropin treatment. The study group (n=50 cycles) was compared with the control group consisting of previous cycles (n=88) of the same women. Significant differences were noted in peak estradiol levels (983 +/- 739 vs. 517 +/- 249 pg/ml; P <0.01, paired Student's t test) and number of pre-ovulatory follicles between the study and the control groups. Thirty-three of the cycles (66%) reached the stage of ovum pick-up, compared with 22 (25%) of the previous IVF cycles in these women. The mean number of oocytes retrieved was 6.1 +/- 3.0 and 2.4 +/- 1.3 in the study and control groups, respectively (P <0.01; paired Student's t test). Embryo transfer (ET) was performed in 62% of the treatment cycles and resulted in five clinical pregnancies (16.1% per ET). No pregnancies were recorded in the control group. This study demonstrates the beneficial effect of OCP given prior to IVF treatment, and provides an efficient treatment modality for women who consistently respond poorly to standard COH protocols.

Endoscopic retrograde cholangiopancreatography and laparoscopic cholecystectomy.

Endoscopic retrograde cholangiopancreatography (ERCP) is a useful adjunct to laparoscopic cholecystectomy. Preoperative ERCP is indicated if there is a high degree of suspicion for common duct stones, when severe gallstone-induced pancreatitis is present, or when there is uncertainty regarding the diagnosis. The best indicators of common duct stones preoperatively are an elevated bilirubin, a dilated common bile duct (CBD) on sonography, or stones visualized in the CBD on sonography. Mild gallstone pancreatitis and transient mild elevations in liver enzymes are not predictive of CBD stones and are not indications for ERCP. Postoperative ERCP is highly effective in clearing CBD stones. It has the advantage of being more readily available as compared to laparoscopic CBD exploration, and preserves all the advantages of the laparoscopic approach. Post-operative ERCP is indicated for retained CBD stones, evaluation and therapy of biliary injuries, and persistent biliary symptoms or abnormal liver enzymes and bilirubin. ERCP is the procedure of choice for the evaluation of laparoscopic biliary injuries. Major biliary injuries will generally require surgical therapy. Bile duct strictures are sometimes amenable to endoscopic therapy with dilation and stents. Biliary leaks are readily treatable with endoscopic therapy. Small cystic duct stump leaks and leaks from a duct of Lushka close within a few days with nasobiliary drainage. Larger leaks may require more prolonged drainage with stents and early supplemental percutaneous drainage of an accompanying biloma. Bilious ascites should be treated with nasobiliary drainage using low suction to be prevent contamination of the peritoneal cavity with intestinal flora, and simultaneous percutaneous ascites drainage. Biliary leaks, unless associated with major bile duct injuries, rarely require surgical therapy.

Esophagitis associated with the use of alendronate.

BACKGROUND: Alendronate, an aminobisphosphonate and a selective inhibitor of osteoclast-mediated bone resorption, is used to treat osteoporosis in postmenopausal women and Paget's disease of bone. Aminobiphosphonates can irritate the upper gastrointestinal mucosa. METHODS: We describe three patients who had severe esophagitis shortly after starting to take alendronate and also analyze adverse esophageal effects reported to Merck, the manufacturer, through postmarketing surveillance. RESULTS: As of March 5, 1996, alendronate had been prescribed for an estimated 475,000 patients worldwide, and 1213 reports of adverse effects had been received. A total of 199 patients had adverse effects related to the esophagus; in 51 of these patients (26 percent), including the 3 we describe in case reports, adverse effects were categorized as serious or severe. Thirty-two patients (16 percent) were hospitalized, and two were temporarily disabled. Endoscopic findings generally indicated chemical esophagitis, with erosions or ulcerations and exudative inflammation accompanied by thickening of the esophageal wall. Bleeding was rare, and stomach or duodenal involvement unusual. In patients for whom adequate information was available, esophagitis seemed to be associated with swallowing alendronate with little or no water, lying down during or after ingestion of the tablet, lying down during or after ingestion of the tablet, continuing to take alendronate after the onset of symptoms, and having preexisting esophageal disorders. CONCLUSIONS: Alendronate can cause chemical esophagitis, including severe ulcerations, in some patients. Recommendations to reduce the risk of esophagitis include swallowing alendronate with 180 to 240 ml (6 to 8 oz) of water on arising in the morning, remaining upright for at least 30 minutes after swallowing the tablet and until the first food of the day has been ingested, and discontinuing the drug promptly if esophageal symptoms develop.

Intranasal nafarelin versus buserelin (short protocol) for controlled ovarian hyperstimulation before in vitro fertilization: a prospective clinical trial.

The aim of this study was to compare the effect of nafarelin acetate with that of buserelin acetate nasal spray, when administered in a 'short' protocol, as an adjunct to human menopausal gonadotropin (hMG) for controlled ovarian hyperstimulation before in vitro fertilization (IVF). Twenty-two IVF subjects were randomly recruited. Each underwent two consecutive treatment cycles; one with buserelin (900 micrograms/day) and another with nafarelin (400 micrograms/day). The treatment protocol included transnasal gonadotropin-releasing hormone (GnRH) analog from the second cycle day and hMG from the fourth day of the cycle. The buserelin and nafarelin cycles did not differ significantly in the following parameters: baseline hormone profile, duration of GnRH analog treatment, mean hMG dose required, peak estradiol levels, number of preovulatory follicles, number of aspirated oocytes, fertilization rate and number of transferred or frozen embryos. No side-effects or cancellations of treatment were recorded. The average dose required was lower for nafarelin and, because this analog was given only twice a day, it was more convenient to administer. These findings suggest that nafarelin is as effective as buserelin (when administered in a "short' protocol) in achieving controlled ovarian hyperstimulation. It even offers advantages over buserelin with respect to the total dose required (which probably reflects its relatively high potency) and the subjects' compliance.

The initial flare-up induced by gonadotropin releasing hormone agonist may serve as a predictor of ovarian response in the current IVF-ET treatment cycle in normogonadotropic women aged 40-48 years.

OBJECTIVE: Our purpose was to assess the potential role of the baseline hormone profile in combination with the initial pattern of response to gonadotropin releasing hormone (GnRH) analogue in predicting ovarian function and hence reproductive outcome in normogonadotropic patients aged 40 years or older undergoing IVF treatment. PATIENTS AND METHODS: A retrospective analysis of 394 controlled ovarian hyperstimulation (COH) cycles that reached the stage of oocyte retrieval was conducted. The study included 163 normogonadotropic (serum FSH < or = 15 IUIL) patients aged between 40 and 48 years who had regular menstrual cycles. Superovulation was achieved using menotropins in combination with GnRH analog (short protocol, beginning on menstrual day 2). The ovarian response was monitored on the third cycle day, the day following the first GnRH analogue administration. RESULTS: Cycle distribution by patient age was 175 (44.4%), 122 (30.9%), and 97 (24.7%), while the patient distribution was 85 (52.2%), 48 (29.5%), and 30 (18.3%) for age groups 40-41, 42-43, and 44-48 years, respectively. The mean total dose of menotropins needed for optimal COH was 1787 IU (range, 600-6000 IU). This dose increased with age, while the yield of oocytes and embryos declined (P < 0.05; ANOVA). A positive correlation was demonstrated between the E2 level on day 3 (GnRH analogue flare effect) and the outcome of the treatment cycle (number of oocytes and embryos). Using multiple stepwise regression analysis, it was demonstrated that the initial (day 3) serum E2 levels, combined with baseline FSH levels, patients's age and body mass index enabled early prediction of the ovarian response in the current IVF-ET treatment cycle (oocytes = 8.2 - 0.18 x Age + 0.17 x BMI - 0.12 x FSH + 0.0042 x E2). CONCLUSIONS: Multiple-parameter analysis demonstrated that the use of the initial E2 response to GnRH analogue stimulation combined with basic clinical data may assist in the prediction of ovarian function and hence the reproductive outcome in normogonadotropic IVF patients aged 40 years or older. This may serve as a clinical tool for improving patient selection and treatment outcome in IVF-ET.

Prolonged evaluation of epinephrine and normal saline solution injections in an acute ulcer model with a single bleeding artery.

BACKGROUND: Animal studies of epinephrine or normal saline solution injection for bleeding ulcers do not consistently demonstrate local tamponade effect. METHODS: We studied the change of bleeding rates of 28 acute gastric ulcers with a single bleeding artery in 10 dogs. Four injections of 1 mL epinephrine 1:10000 at 1 mm from the spurting artery (n = 7) were compared to four injections of normal saline solution 1 to 5 mL (n = 12) and to four dry needle sticks (n = 9). Bleeding rates were measured at initial arterial incision and at minutes 1, 5, 10, 15, 20, 25, and 30 after treatment. RESULT: Reductions in early blood loss to 24.3% +/- .05 of baseline occurred with saline solution, to 17.7% +/- .03 with epinephrine, and to 66.0% +/- 1.8 in controls (p < .05 for epinephrine and saline solution vs control). A tendency for saline solution injected ulcers to resume bleeding was identified, with late blood loss increasing to 26.9% +/- .05 of baseline, (saline solution vs control) compared to 7.7% +/- .02 in epinephrine injected ulcers (p < .05 vs control). CONCLUSIONS: The early acute hemostatic effect of injection therapy depends on local tamponade. The prolonged hemostatic effect is a combination of tamponade and vasoconstriction, with advantage of epinephrine over saline solution.

Endoscopic basket impaction.

Endoscopic Retrograde Cholangiopancreatography (ERCP) is an indispensable tool for imaging the pancreatico-biliary tree, and in treating diseases of the pancreatic and biliary systems. ERCP plays a primary role in the management of choledocholithiasis, both in diagnosis and treatment. Complications occur infrequently and can usually be treated nonoperatively. An unusual complication of ERCP and an impacted stone retrieval basket are presented and discussed along with review of the medical literature.

Assisted hatching by partial zona dissection of human pre-embryos in patients with recurrent implantation failure after in vitro fertilization.

OBJECTIVE: To examine the potential of the partial zona dissection technique to promote successful implantation by assisting embryo hatching after IVF. DESIGN: The study and the control group included 72 and 82 patients, respectively, each had undergone at least three failed IVF-ET attempts. Assisted hatching was performed on four- to six-cell stage embryos by creating a slit in the zona pellucida using the partial zona dissection technique. After 90 minutes incubation (5% CO2, 37 degrees C), the embryos were transferred to the uterus. SETTING: Infertility and IVF Unit of an academic tertiary referral medical center. RESULTS: In the assisted hatching group, 230 micromanipulated embryos were replaced (3 or 4 treated embryos per patient) compared with 295 nonmanipulated embryos in the control group. Clinical pregnancy rates (PRs) were similar in the assisted hatching and control groups (n = 15; 20.8% and n = 12; 14.6%, respectively). However, the contribution of assisted hatching by partial zona dissection to successful implantation was related to the patients's age: patients older than 38 years showed a markedly higher PR after assisted hatching: 23.9% in the study group compared with only 7% of the controls. CONCLUSIONS: These results demonstrate that assisted hatching by partial zona dissection is a quick and efficient method that does not induce any visible damage to the embryos replaced. In a selected group of patients (aged over 38 years, who have failed to conceive in at least three previous IVF attempts) it significantly increases the chances for pregnancy after ET.