Search PubMed⌕ Search

Biomedical subjects

D Levran

Publications and source records attributed to D Levran.

At least 19 recordsLinked to original sources

Zygote intrafallopian transfer in patients with tubal factor infertility after repeated failure of implantation with in vitro fertilization-embryo transfer.

OBJECTIVE: To evaluate the efficacy of zygote intrafallopian transfer (ZIFT) in terms of implantation and pregnancy rates in patients with tubal factor infertility and repeated implantation failure in IVF-ET cycles. DESIGN: Retrospective analysis of ZIFT cycles. SETTING: An IVF unit in a university hospital. PATIENT(S): Criteria for patient selection for ZIFT included at least four failures of implantation in IVF-ET cycles in which at least 3 embryos were replaced per transfer and a cause of infertility diagnosed as male, unexplained, or tubal factor with proof of one patient tube. INTERVENTION(S): Four to six zygotes were transferred by laparoscopy into the fallopian tube 24-26 hours after oocyte retrieval. MAIN OUTCOME MEASURE(S): Implantation and pregnancy rates were determined in 112 ZIFT cycles performed in 81 patients with repeated failure of implantation. Results were further stratified for patients with tubal factor (n = 15) and patients without tubal factor (n = 66). RESULT(S): The pregnancy and implantation rates for all ZIFT cycles were 35.1% and 11.1%, respectively. Pregnancy and implantation rates per cycle in patients with tubal factor versus patients without tubal factor were 26.6% versus 37.1% and 9.4% versus 11.4%, respectively. CONCLUSION(S): ZIFT can be considered as a mode of treatment for patients with repeated failure of implantation in IVF-ET and with tubal factor with proved patency of one tube.

Embryo Implantation↗

Estradiol supplementation during the luteal phase may improve the pregnancy rate in patients undergoing in vitro fertilization-embryo transfer cycles.

OBJECTIVE: To evaluate the effect of adding E(2) to progestin supplementation during the luteal phase on pregnancy and implantation rates in patients undergoing IVF cycles. DESIGN: Prospective, randomized study. SETTING: An IVF unit in a university hospital. PATIENT(S): Patients who were undergoing IVF with controlled ovarian hyperstimulation using a GnRH analog and who had E(2)2,500 pg/dL at the time of hCG administration. INTERVENTION(S): Serum concentrations of E(2) and progesterone were measured in all patients on days 7, 10, and 12 after ET. MAIN OUTCOME MEASURE(S): The E(2) and progesterone profiles of the luteal phase and the pregnancy and implantation rates were documented. Data were analyzed for the entire study population and further stratified according to the GnRH analog protocol used (short or long). RESULT(S): Significantly higher E(2) levels were found during the luteal phase in the group that received E(2) supplementation. This effect was more pronounced in the patients who were treated with the long GnRH analog protocol. Significantly higher pregnancy and implantation rates were recorded in the patients who received E(2) supplementation and were treated with the long GnRH analog protocol. CONCLUSION(S): For patients who are treated with the long GnRH analog protocol for controlled ovarian hyperstimulation and for whom luteal support with hCG is contraindicated, the addition of E(2) to the progestin support regimen may have a beneficial effect on pregnancy and implantation rates.

Adult↗

Testicular sperm aspiration and intracytoplasmic sperm injection for persistent infection of the ejaculate.

OBJECTIVE: To report the successful use of testicular sperm aspiration and intracytoplasmic sperm injection in the presence of an Escherichia coli-infected ejaculate that previously caused repeated embryo degeneration. DESIGN: Case report. SETTING: University medical center. PATIENT(S): A 38-year-old woman who did not conceive for 6 years with repeated IVF attempts. Escherichia coli was isolated from both the oocyte culture dish and her male partner's ejaculate. INTERVENTION(S): Testicular sperm aspiration and intracytoplasmic sperm injection followed by ET. MAIN OUTCOME MEASURE(S): Clinical outcome. RESULT(S): Establishment of a pregnancy delivered at term. CONCLUSION(S): Patients undergoing IVF treatment who have repeated embryo degeneration caused by bacterial infection originating in the ejaculate may be treated successfully with testicular sperm aspiration and intracytoplasmic sperm injection.

Adult↗

The best donor.

Oocyte donation has become a common treatment modality for a large spectrum of infertility conditions. The purpose of this study was to assess the success rate of a shared egg donation programme, and to define the profile of a successful 'donor-recipient' couple in view of the limitations imposed by the shared programme. The results of all consecutive cycles of egg donation from 1st January 1995 to 31st December 1996 were analysed. A total of 383 donor cycles were matched with 946 recipient cycles; clinical pregnancy rates were 23. 5 and 16.7% respectively. With the exception of endometriosis, which significantly reduced the pregnancy rate in both groups, similar pregnancy rates were obtained in both groups for all the other infertility aetiologies of the donors. The donor's age had no impact on pregnancy rate of the recipient, but pregnancy rate was significantly decreased in donors >35 years. Recipients >50 years had significantly reduced pregnancy rates and those >45 years a significantly increased abortion rate. Recipients with severe male factor infertility, who had intracytoplasmic sperm injection treatment, showed pregnancy rates equivalent to those recipients who had regular in-vitro fertilization. We conclude that in a shared egg donation programme, the recipients' pregnancy rate and outcome are dependent only on the donors' infertility aetiologies and on recipients' ages.

Adolescent↗

ART success and in vivo sperm cell selection depend on the ultramorphological status of spermatozoa.

Management of male infertility has recently shifted from treatment of the subfertile man towards techniques of assisted reproduction (ART). This study aimed to evaluate the possible role of the ultramorphological status of the spermatozoon with respect to sperm selection in vivo and prediction of ART success. Ultramorphological sperm parameters were assessed retrospectively for 92 males with sufficient sperm density (10(7) spermatozoa ejaculate-1) whose wives conceived following a stepwise discarding of the female genital tract barriers, using intra-uterine insemination (IUI) (n = 26), in vitro fertilization (IVF) (n = 45) or intracytoplasmic sperm injection (ICSI) (n = 21). In parallel, sperm samples of 71 fertile males were examined. Normal ultramorphology of all head and tail subcellular organelles was found to be essential for the ability of spermatozoa to pass the lower female genital tract. The ultramorphological migration threshold for this barrier is apparently higher than that essential for oocyte fertilization. No specific indication associated with passage through the upper genital tract was found. A high prevalence of axonema defects was found to impair the ability of sperm cells to penetrate the oocyte investment. The natural fertility index, based on routine sperm parameters and the ultrastructural status of the spermatozoon's subcellular organelles was confirmed to be beneficial for directing patients to ART. A discriminative score based on axonema integrity was found to contribute additional information for the first choice decision between conventional ART and ICSI (75% prediction ability). Thus it may be helpful in finding the simplest and least expensive procedure with the greatest long-term chance for pregnancy.

Female↗

Fetal enterolithiasis and anhydramnios; due to in utero hepatorenal syndrome?

Enterolithiasis is a rare, prenatal ultrasonographic finding. Previously reported cases were invariably associated with major fetal malformations. We describe a case of fetal enterolithiasis and anhydramnios in an anatomically normal fetus who, at autopsy, showed end-stage fetal liver disease. Fetal hepatorenal syndrome is the most probable cause of this in utero sonographic combination.

Adult↗

Zygote intrafallopian transfer may improve pregnancy rate in patients with repeated failure of implantation.

OBJECTIVE: To evaluate the efficacy of zygote intrafallopian transfer (ZIFT) on implantation rates and pregnancy rates (PRs) in patients with repeated failure of implantation in IVF-ET cycles. DESIGN: A case-control study. PATIENT(S): Criteria for patient selection included male factor or unexplained infertility, normal uterine cavity, and at least three failures of implantation in IVF-ET cycles in which at least three embryos were placed per transfer. Data on 70 patients who underwent 92 ZIFT cycles are presented. A control group consisted of patients with the same selection criteria who underwent an additional standard IVF-ET cycle during the same time period. INTERVENTION(S): Ovulation induction consisted of down-regulation with GnRH analogue followed by ovarian stimulation with FSH and hMG. Intracytoplasmic sperm injection was performed on the oocytes of all patients with male factor infertility. Zygotes were transferred by laparoscopy into the fallopian tube 24-26 hours after oocyte retrieval. MAIN OUTCOME MEASURE(S): Implantation rates and PRs in the ZIFT and control groups were compared. RESULT(S): The PRs and implantation rates were significantly higher in the ZIFT group than in the control group: 34.2% (24/70) and 8.7% (29/333) versus 17.1% (12/70) and 4.4% (13/289), respectively (P = 0.002 and P = 0.04). The cumulative conception rate for two ZIFT cycles was 59.3%. CONCLUSION(S): Zygote intrafallopian transfer should be considered a beneficial mode of treatment for patients with repeated failure of implantation in IVF and transcervical ET. More prospective randomized studies are needed to support this observation.

Adult↗

Outcome of in vitro fertilization and intracytoplasmic injection of epididymal and testicular sperm extracted from patients with obstructive and nonobstructive azoospermia.

OBJECTIVE: To evaluate IVF outcome after epididymal and testicular sperm retrieval in patients with obstructive or nonobstructive azoospermia. DESIGN: Retrospective clinical analysis. SETTING: Public university-affiliated IVF unit. PATIENT(S): One hundred twenty-three azoospermic patients (178 cycles). INTERVENTION(S): Sixty-three patients (103 cycles) with obstructive azoospermia (group 1) underwent either epididymal or testicular sperm retrieval, and 60 patients (75 cycles) with nonobstructive azoospermia (group 2) underwent testicular sperm retrieval combined with IVF treatment. Mature oocytes were fertilized using intracytoplasmic sperm injection. After sperm preparation, supernumerary spermatozoa were cryopreserved. MAIN OUTCOME MEASURE(S): Oocyte fertilization rate and clinical pregnancy rate (PR). RESULT(S): The oocyte fertilization rate was 48.4% (534/1,104) in group 1 and 41.5% (312/751) in group 2 (not significant [NS] difference). A total of 100 cycles (97.1%) and 62 cycles (82.7%) in the obstructive and nonobstructive groups, respectively, had embryos for replacement (NS difference). The clinical PRs per ET cycle were 24% (24/100) and 17.7% (11/62) in the two groups, respectively. Oocyte fertilization rates, when fresh (46.4%) or frozen-thawed (41.8%) spermatozoa were used, were not significantly different in the two groups. The PR when fresh sperm were used was 23.6% (30/127), versus 14.3% (5/35) when frozen sperm were used (NS difference). The PR for women aged < or = 35 years was similar to that for women >35 years of age (20.7% or 29/140 and 18.2% or 4/25, respectively). CONCLUSION(S): Epididymal and testicular sperm obtained in azoospermic patients can fertilize oocytes successfully and may lead to high fertilization rates and PRs. Freezing of these spermatozoa does not reduce the outcome of treatment significantly.

Adult↗

In vitro fertilization treatment for severe male factor: a comparative study of intracytoplasmic sperm injection with testicular sperm extraction and with spermatozoa from ejaculate.

PURPOSE: Our purpose was to evaluate whether the source of spermatozoa influences the results of intracytoplasmic sperm injection (ICSI) treatment in couples with severe male-factor infertility. METHODS: A retrospective analysis of 40 cases of ICSI with testicular-retrieved spermatozoa, matched with 40 cases of ICSI with ejaculated spermatozoa, was performed. We included only couples with normoovulatory females younger than 37 years who were matched according to the day of ovum pickup with the patients in the study group. RESULTS: Eighty cycles were analyzed: 40 cycles using testicular spermatozoa and 40 cycles using ejaculated spermatozoa. In 32 (80%) of the 40 ICSI transcutaneous needle aspiration cycles, we obtained enough spermatozoa to inject all the mature oocytes retrieved. In eight (20%) cases there were not enough spermatozoa to inject all the oocytes. Only 76 (54%) of 141 available oocytes were injected in these eight patients. The oocyte fertilization rates were 42% for the study group and 55.5% for the controls (P < 0.005). Thirty-six (90%) patients in the group with nonobstructive a zoospermia (NOA) and 37 (92.5%) patients in the oligoteratoasthenospermia (OTA) group had embryos for replacement. The mean cleavage rates per cycle (96% with testicular and 93% with ejaculated spermatozoa), the mean number of embryos per transfer (3.72 +/- 1.6 in the NOA group and 4.24 +/- 1.5 in the OTA group), the embryo quality (cumulative embryo scoring = 34.03 +/- 22.62 in the testicular sperm group and 36.08 +/- 19.28 in the ejaculated sperm group), and the clinical pregnancy rates (22.5% in the NOA patients and 20% in the ejaculate group) were not significantly different between groups. CONCLUSIONS: High fertilization, cleavage, and pregnancy rates can be achieved with intracytoplasmic testicular sperm injection from patients with NOA, reaching levels comparable with those of ICSI using ejaculated spermatozoa.

Adult↗

The outcome of in-vitro fertilization treatment by egg donation and intracytoplasmatic sperm injection for severe male factor infertility: a preliminary report.

Due to a paucity of donated eggs, we have excluded, until recently, couples with severe male factor infertility from our egg donation programme, except for those who accepted insemination with donor spermatozoa. The purpose of this study was to assess the feasibility of a shared in-vitro fertilization (IVF)-embryo transfer treatment whenever the recipients have severe oligoasthenoteratozoospermia (OTA) and need intracytoplasmic sperm injection (ICSI) for egg fertilization. The results from 163 consecutive couples with ovarian failure who underwent 273 cycles of IVF with donated eggs and augmented with ICSI were analysed. The rate of diploid fertilization was 54.7%; in 92.3% of the cycles, at least one embryo was available for transfer. Forty-seven clinical pregnancies were achieved, representing 18.6% conceptions per transfer. The highest pregnancy rate was achieved in menopausal patients aged 40-45 years (26.2% per cycle) and the lowest in patients >45 years old (10.8% per cycle, P = 0.03). Overall, 28.8% of the couples achieved a clinical pregnancy. A total of 196 treatment cycles resulted in 46 clinical pregnancies (23.5%) among the donors. No statistical differences were found in pregnancy rate achieved by the donors when compared with the recipients. We conclude that ICSI with egg donation is a reliable treatment in patients with ovarian failure and severe OTA.

Adult↗

Incubation with sperm enhances in vitro maturation of the oocyte from the germinal vesicle to the M2 stage.

OBJECTIVE: To evaluate the effect of sperm in the culture medium on the rate of oocyte maturation in vitro from the germinal vesicle to the M2 stage. DESIGN: Prospective randomized controlled study. SETTING: The IVF Unit, Wolfson Medical Center, Holon, Israel. PATIENT(S): All women in whom oocytes were retrieved at the germinal vesicle stage between December 1995 and March 1996. INTERVENTION(S): Oocytes retrieved at the germinal vesicle stage were divided prospectively and randomly into four groups of incubation conditions: group 1, intact germinal vesicle with cumulus; group 2, intact germinal vesicle with sperm cells in the culture medium; group 3, stripped germinal vesicle; and group 4, stripped germinal vesicle with sperm cells. Oocytes were observed 24 hours after retrieval, and the stage of maturation was recorded. Oocytes that reached the M2 stage underwent the intracytoplasmic injection procedure, and the fertilization rate in each group was recorded at 48 hours. MAIN OUTCOME MEASURE(S): Maturation rate from the germinal vesicle to M2 stage and fertilization rate. RESULT(S): Each group contained 20 germinal vesicle oocytes. In groups 1 and 2, 2 (10%) and 9 (45%) oocytes, respectively, reached the M2 stage at 24 hours; at 48 hours, 1 (5%) and 8 (40%) embryos developed, respectively. The results in group 2 were significantly higher than in group 1. In groups 3 and 4, 6 (30%) and 16 (80%) oocytes, respectively, reached the M2 stage at 24 hours; at 48 hours, 5 (25%) and 14 (70%) embryos developed, respectively. Results in group 4 were significantly higher than those in groups 1, 2, and 3. CONCLUSION(S): Both methods of oocyte activation (i.e., addition of sperm to the culture medium or removal of the cumulus) enhance oocyte maturation in vitro, but the sperm-incubation method has a more pronounced effect. A combination of both methods leads to an exceptionally high rate of oocyte maturation, followed by a high fertilization rate.

Adult↗

Cumulative pregnancy rate following in-vitro fertilization: the significance of age and infertility aetiology.

During the years 1984-1992, 951 couples completed 2252 in-vitro fertilization (IVF) treatment cycles at the In-Vitro Fertilization Unit of The Chaim Sheba Medical Centre. This study was conducted to evaluate the success of IVF using the cumulative pregnancy rate (CPR), with special emphasis on the optimal number of treatment cycles, the age of the patients and female infertility factors. It was found that the CPR showed a constant rise during the six initial IVF treatments (56% CPR), and plateaued in the subsequent three cycles (63% CPR). Various female infertility factors did not influence this rate. Women > or = 40 years of age have a significantly lower CPR. Thus, it was concluded that the CPR in IVF declined after the sixth initial treatment cycle, and in women > or = 40 years of age. The infertility factor did not significantly influence CPR.

Adult↗

Micromanipulation improves in-vitro fertilization results after epididymal or testicular sperm aspiration in patients with congenital absence of the vas deferens.

In all, 58 couples suffering from infertility because of congenital bilateral absence of the vas deferens underwent a total of 67 combined microsurgical epididymal aspiration or testicular sperm extraction (TESE) and in-vitro fertilization (IVF) treatments. The oocytes recovered were inseminated by either the microdroplet IVF technique (N = 20), subzonal insemination (SUZI; n = 10) or intracytoplasmic sperm injection (ICSI; n = 37). Of the ICSI cycles, 12 were performed using spermatozoa obtained by TESE. Fertilization rates for epididymal spermatozoa were significantly higher for SUZI (17.9%, 17/95) and ICSI (34.4%), 137/398) than for microdroplet IVF (5.2%, 18/343) cycles. The proportion of cycles in which fertilization was achieved was higher in the SUZI (80%) and ICSI (95%) cycles than in the IVF cycles (45%). Delivery or an ongoing pregnancy was achieved in one (5%) IVF cycle, two (20%) SUZI cycles and seven (18.95) ICSI cycles. SUZI or ICSI using epididymal or testicular spermatozoa significantly improved the oocyte fertility rate. The ICSI procedure was especially advantageous in patients for whom spermatozoa were obtained from a testicular biopsy.

Cytoplasm↗

Parameters that influence the results of in vitro fertilization/embryo transfer: a study of an egg donation model.

A retrospective analysis was carried out after ovulation induction in donors, and treatment outcome in donors and recipients, relating to variables such as: age, protocol of ovarian stimulation, transfer of fresh or cryopreserved embryos, number of embryos transferred including quality and etiology of donor and recipient infertility. The recipients underwent 214 cycles of embryo transfer from 82 different donors. Forty-five (21%) pregnancies were recorded. The age of the recipients significantly affected the conception rate (pregnancy rate of 30% in those aged < 30 years, compared to 9.7% in those aged > 44 years) and the donors were contributed more to pregnancies were also younger. The pregnancy rate was significantly higher when fresh embryos were transferred to recipients (28%, compared to 15% when cryopreserved embryos were transferred). In addition, the number of embryos transferred affected the pregnancy rate if > or = 3 embryos were transferred and, if they were of good quality, the success was significantly higher. Ultimately, when the ovarian stimulation protocol was clomiphene citrate and human menopausal gonadotropin or gonadotropin-releasing hormone agonist/follicle-stimulating hormone/human menopausal gonadotropin, and the etiology of infertility was polycystic ovarian disease in the donors, the success rate was significantly increased in the recipients.

Abortion, Spontaneous↗

A randomized study of intracytoplasmic sperm injection (ICSI) versus subzonal insemination (SUZI) for the management of severe male-factor infertility.

OBJECTIVE: Our objective was to compare the fertilization rates achieved by ICSI versus SUZI in couples with severe male infertility. DESIGN: This was a randomized, prospective study. SETTING: The study took place at the In-Vitro Fertilization-Embryo Transfer Unit, Department of Obstetrics and Gynecology, The Chaim Sheba Medical Center. MATERIALS AND METHODS: Oocytes of 12 patients were randomly allocated to either ICSI or SUZI procedures. Each woman thus served as her own control. All 12 patients had undergone at least two previous in vitro fertilization cycles with no fertilization or had a very low sperm count, i.e., a total motile sperm count of less than 0.5 x 10(6). RESULTS: A total of 117 oocytes was obtained for fertilization. Of these oocytes, 16% (10/63) were successfully fertilized by SUZI, compared to 33% (18/54) treated by ICSI. This difference was statistically significant (P < 0.05). Of the 12 cycles, ICSI provided embryos in 10 cycles (83%), while SUZI was successful in only 6 cycles (50%). Four pregnancies were achieved: 33% per attempt, or 40% per transfer.

Adult↗

Endometrial blood flow response to hormone replacement therapy in women with premature ovarian failure: a transvaginal Doppler study.

OBJECTIVE: To evaluate the endometrial blood flow response to hormone replacement therapy (HRT) in women with premature ovarian failure who plan to enter an oocyte donation program. DESIGN: Transvaginal color Doppler ultrasound examinations were performed in women with ovarian failure before and during a cycle of standard HRT and in those with normal menstrual cycles. Blood flow response was assessed by visualization of arterial wave forms in the endometrial region. The transvaginal color flow mapping system was used. Resistance indexes were calculated for analysis and correlated with plasma E2 and P concentrations. PATIENTS: Eighteen women with ovarian failure (study group), and 12 volunteers with normal ovarian cycles (control group). RESULTS: Data for resistance indexes were divided into five phases according to the day of hormonal cycle: 0, pretreatment phase; I, early follicular phase (days 5 to 7); II, late follicular phase (days 11 to 13); III, early luteal phase (days 17 to 21); and IV, late luteal phase (days 23 to 25). All women with ovarian failure demonstrated continuous forward end-diastolic flow velocities at phase I, whereas none showed this pattern during the pretreatment period (phase 0). Women with ovarian failure in the early follicular phase had a significantly higher resistance index (0.85 +/- 0.1; mean +/- SD) than that in the late follicular phase (0.57 +/- 0.1), and the resistance index in the early luteal phase (0.67 +/- 0.1) was significantly higher than that of the late follicular phase. There was no difference in the resistance index between early and late luteal phases. A similar pattern of lower resistance index around midcycle was observed in the control group. However, a comparison of the resistance indexes between ovarian failure and control patients revealed a significant difference between values in the early follicular phase only (0.85 +/- 0.1 versus 0.68 +/- 0.1). In the late follicular phase and during the entire luteal phase, the mean resistance index did not differ between the study and control groups. CONCLUSIONS: The observed data suggest that standard HRT in women with premature ovarian failure enables restoration of endometrial blood flow to normal. This may imply uterine receptivity for oocyte donation.

Diastole↗

Adjuvant growth hormone therapy in poor responders to in-vitro fertilization: a prospective randomized placebo-controlled double-blind study.

The objective of the study was to assess the effect of growth hormone (GH) supplementation to a combined gonadotrophin-releasing hormone agonist/human menopausal gonadotrophin (GnRHa/HMG) treatment protocol on ovarian response in 'poor responders' undergoing in-vitro fertilization (IVF). GH or a placebo were administered in a prospective randomized double-blind manner. A total of 14 poor-responder patients (oestradiol < 500 pg/ml, less than three oocytes retrieved in two previous IVF cycles) were randomly allocated to a combined treatment of either GnRHa/HMG/GH (18 IU on alternate days, total dose 72 IU) or GnRHa/HMG placebo. No difference was found between the study and control groups in the number of HMG ampoules used, the number of follicles (> 14 mm) and serum oestradiol concentrations on the day of administration of human chorionic gonadotrophin (HCG), the number of oocytes retrieved and fertilized, and the number of embryos transferred. The GH group (n = 7) did not show a better ovulatory response in the study cycles; mean +/- SD serum oestradiol on day of HCG 411 +/- 124 versus 493 +/- 291 pg/ml, aspirated oocytes 2.2 +/- 1.5 versus 1.9 +/- 2.0. Interestingly, when the above results for the placebo group were compared with their previous cycles (serum oestradiol 403 +/- 231 pg/ml; 0.4 +/- 0.5 aspirated oocytes), a non-specific effect was found. Follicular recruitment, oestradiol secretion by mature follicles and the number of oocytes retrieved in poor responders were not improved by GH supplementation.

Adult↗

A reappraisal of the feedback effects of oestradiol upon luteinizing hormone surge.

The objective of this study was to assess the temporal relationships of serum oestradiol and luteinizing hormone (LH) with regard to the feedback mechanism leading to the LH surge. Daily measurements of oestradiol, LH and follicle stimulating hormone were made in 65 women with ovarian failure undergoing an evaluation of endometrial response to oral cycle stimulation. Patients received incremental oral oestradiol valerate for varying durations at the in-vitro fertilization unit of the Sheba Medical Center, Tel Hashomer, Israel. The treatment protocol involved the administration of daily oestradiol valerate, starting with 1 mg/day, followed by a daily increment of 1 mg for a total of 4, 6 and 8 days. After the last day, a daily maintenance dose of 2 mg was continued. Serum oestradiol concentrations correlated with the dose of oral oestradiol valerate. Peak oestradiol concentrations (mean +/- SEM) were 572 +/- 60, 721 +/- 42 and 797 +/- 53 pg/ml for 4, 6 and 8 days of oestradiol valerate administration respectively. Serum LH, after an initial suppression, peaked 2 days after maximal oestradiol valerate dose and 1 day after peak serum oestradiol. The magnitude of the LH peak was proportional to the duration of incremental oestradiol valerate treatment. In conclusion, the LH surge is temporally related to the cessation of serum oestradiol increase. Consequently, the occurrence of this surge can be explained by a simple negative feedback inhibition of pituitary LH release rather than by a dual negative/positive mechanism.

Adult↗