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Dive into the research topics where Fredesminda Hamilton is active.

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Featured researches published by Fredesminda Hamilton.


Fertility and Sterility | 1991

LOWER PREGNANCY RATE WITH PREMATURE LUTEINIZATION DURING PITUITARY SUPPRESSION WITH LEUPROLIDE ACETATE

W.B. Schoolcraft; Eleanor Sinton; Terry Schlenker; David Huynh; Fredesminda Hamilton; David R. Meldrum

The relationship of the circulating level of progesterone (P) on the day of human chorionic gonadotropin (hCG) injection to occurrence of clinical pregnancy was examined in 133 leuprolide acetate human menopausal gonadotropin (hMG) in vitro fertilization cycles in women having at least three embryos transferred. Progesterone concentrations greater than 0.5 ng/mL were associated with a significantly lower rate of pregnancy (12/59, 20%) compared with less than 0.5 ng/mL (40/74, 54%, P less than 0.005). The higher P cycles were associated with greater patient age and hMG dose, although these relationships appeared to be indirect. Luteinizing hormone (LH) concentrations remained suppressed. Ovarian stimulation may cause excessive luteinization and an adverse cycle outcome even in the presence of low LH levels. Prospective use of P levels may be helpful to determine optimal hCG timing.


Fertility and Sterility | 1999

Blastocyst culture and transfer: analysis of results and parameters affecting outcome in two in vitro fertilization programs

W.B. Schoolcraft; David K. Gardner; Michelle Lane; Terry Schlenker; Fredesminda Hamilton; David R. Meldrum

OBJECTIVE To determine whether previously described advanced blastocyst development and high implantation rates are confirmed in an expanded multicenter trial. DESIGN Retrospective review. SETTING Two private assisted reproductive technology units. PATIENT(S) One hundred seventy-four patients who underwent blastocyst culture and transfer. INTERVENTION(S) Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5) followed by ET. MAIN OUTCOME MEASURE(S) The number and percentage of blastocysts developed, implantation rates, pregnancy rates, and parameters that affected outcome were analyzed. RESULT(S) Only 3 of 174 patients failed to achieve blastocyst-stage ET. The mean blastocyst development rate was 48%. The ongoing pregnancy rate was 66.3% per oocyte retrieval, with a mean (+/-SE) of 2.2 +/- 0.05 blastocysts transferred and an implantation rate of 48% per blastocyst transferred. CONCLUSION(S) Blastocyst culture and transfer is an effective means of treating patients who respond well to gonadotropins. High pregnancy rates can be accomplished with low numbers of embryos transferred. Patients who failed to achieve ET were rare.


Fertility and Sterility | 1989

Routine pituitary suppression with leuprolide before ovarian stimulation for oocyte retrieval

David R. Meldrum; Arthur Wisot; Fredesminda Hamilton; Ana Lisa Gutlay; Wendy Kempton; David Huynh

Pituitary suppression with leuprolide acetate (LA) was used before and during ovarian stimulation with human menopausal gonadotropins in 45 consecutive women having their first cycle of in vitro fertilization embryo transfer (IVF-ET). As anticipated, a low rate of cycle cancellation (6.7%) was necessary for poor responses. Follicles were allowed to develop to a larger diameter than with our prior protocol without LA. On the day of human chorionic gonadotropin (hCG), 11.5 + 0.7 follicles of at least 1.0 cm were visualized; 11.7 + 0.9 oocytes were retrieved; 67.5% fertilized and 6.7 + 0.6 normal embryos were available for transfer. Of the 3.4 + 0.1 embryos transferred per patient, 24.6% implanted. The rates of clinical pregnancy per retrieval and per stimulation were 54% and 47%, respectively, of which 23.8% aborted. Routine use of LA resulted in a highly efficient level of ongoing pregnancy per initiated cycle, and therefore may produce a superior first cycle for IVF-ET.


Fertility and Sterility | 1988

Timing of initiation and dose schedule of leuprolide influence the time course of ovarian suppression

David R. Meldrum; Arthur Wisot; Fredesminda Hamilton; Ana Lisa Gutlay; David Huynh; Wendy Kempton

The time course of suppression of ovarian estrogen production and follicular development with leuprolide was examined in 40 normal women before ovarian stimulation for in vitro fertilization (IVF). Initiation of leuprolide during the midluteal phase caused a significantly more prompt suppression than when treatment was started during the early follicular phase (day 1). Injection of the same total amount of leuprolide in two divided doses also caused a significantly more prompt suppression. These two methods were consistent enough to make routine use of leuprolide practical before ovarian stimulation for IVF.


Fertility and Sterility | 1990

Leuprolide acetate lowers circulating bioactive luteinizing hormone and testosterone concentrations during ovarian stimulation for oocyte retrieval

Marcelle I. Cedars; Eric Surey; Fredesminda Hamilton; Phillip Lapolt; David R. Meldrum

Levels of immunoreactive luteinizing hormone (LH), bioactive LH, and testosterone (T) were determined in 52 women receiving human menopausal gonadotropins (hMG). In 26 women receiving leuprolide acetate (LA) preceding hMG, there was a significant suppression of immunoreactive LH and bioactive LH. The characteristic increase in serum levels of bioactive LH and T were absent. Follicular fluid estradiol and T concentrations, and serum progesterone were not different. The lower circulating levels of T may reflect reduced LH-stimulated androgen accumulation in smaller nonaspirated follicles and may account for the enhanced follicle recruitment observed during LA. The lack of premature luteinization despite marked rises of bioactive LH in the absence of LA is consistent with normal events during the menstrual cycle and was due to the early termination of hMG stimulation.


Journal of Assisted Reproduction and Genetics | 1998

Assisted hatching reduces the age-related decline in IVF outcome in women younger than age 43 without increasing miscarriage or monozygotic twinning

David R. Meldrum; Arthur Wisot; Bill Yee; Gabriel Garzo; Lisa Yeo; Fredesminda Hamilton

PurposeOur purpose was to examine the benefits of assisted hatching in our program and to determine whether the procedure increases the implantation of nonviable embryos or monozygotic twinning.MethodsConsecutive in vitro fertilization cycles using assisted hatching were compared with historical controls. The impact of assisted hatching was analyzed according to the woman’s age. Outcome measures were clinical pregnancy, implantation rate, delivery rate, multiple pregnancy, spontaneous abortion, and incidence of monozygotic twins.ResultsThe implantation rate was increased in women aged 35–39 and markedly increased in women aged 40–42. There was no change in spontaneous abortions and no increase in monozygotic twins.ConclusionsAssisted hatching is a safe and highly effective adjunct to in vitro fertilization for women aged 35–42 and did not increase spontaneous abortion or monozygotic twinning.


Fertility and Sterility | 1989

Artificial agonadism and hormone replacement for oocyte donation

David R. Meldrum; Arthur Wisot; Fredesminda Hamilton; Ana Lisa Gutlay-Yeo; Bivian Marr; David Huynh

Use of donor oocytes appears to enhance the success of in vitro fertilization (IVF) and embryo transfer (ET) by avoiding the adverse effects of ovarian stimulation on the recipient endometrium. In a donor egg recipient with menstrual function, we created an agonadal state with leuprolide acetate followed by hormonal replacement to allow precise synchronization with the donor. Her second transfer cycle resulted in a triplet pregnancy


Fertility and Sterility | 1994

Successful pregnancies with unstimulated cycle oocyte donation using an antagonist of gonadotropin-releasing hormone *

David R. Meldrum; Jean Rivier; Gabriel Garzo; Arthur Wisot; Cathy Stubbs; Fredesminda Hamilton

We achieved two ongoing pregnancies in five older recipients with natural cycle oocyte donation from five young donors using a GnRH antagonist, with hMG and hCG to complete oocyte maturation. This provides a new alternative to ovarian stimulation for both oocyte donation and routine IVF.


Journal of Assisted Reproduction and Genetics | 1985

Optimization of hydrogen-ion concentration during aspiration of oocytes and culture and transfer of embryos

Ryszard J. Chetkowski; Thomas E. Nass; Dennis W. Matt; Fredesminda Hamilton; Kenneth A. Steingold; Denise Randle; David R. Meldrum

Rapid and marked shifts in pH can have deleterious effects on oocytes and embryos. Such shifts are most likely to occur during laparoscopy and examination of gametes and embryos. We studied the rate of pH change of follicular fluid and bicarbonate- and phosphate-based media during exposure to 100% CO2 with a constant surface area to volume ratio. All solutions tested developed a pH below the physiological range of 7.30–7.50 within 2 min of expoure to 100% CO2. We also examined the rate of increase in pH due to CO2 loss from media in room air within standard organ culture dishes and tubes after exposure to ambient conditions for 2 min, the pH of modified Hams F-10 medium in organ culture dishes rose above the physiological range. We have used a needle laparoscope to confirm intraperitoneal placement prior to the insufflation of a 5% CO2 gas mixture for loparoscopic oocyte retrieval. We have carried out all examinations of oocytes and embryos within a pediatric isoette equipped with an automatic CO2 controller to maintain a 5% CO2 environment. We have transferred embryos in 15% fetal cord serum to avoid the alkaline pH associated with a high concentration of equilibrated heat-inactivated preovulatory serum. These simple techniques can optimize the hydrogen-ion concentration of media during the entire process of in vitro fertilization and embryo transfer.


Fertility and Sterility | 1987

Factors influencing maintenance of sperm motility during in vitro processing.

Dominique de Ziegler; Marcelle I. Cedars; Fredesminda Hamilton; Tracy Moreno; David R. Meldrum

Addition of serum to culture medium during washing of sperm was shown to significantly improve sperm motility upon subsequent 24-hour incubation, distinct from the beneficial effects of adding serum after washing. Commercial sources of human and bovine albumen tested did not preserve motility as well as serum, but addition to serum showed that the lesser effect was probably due to toxic contaminants. One of the most commonly available disposable plastic syringes was found to be markedly toxic to sperm. The materials found to have sperm toxicity also manifested toxicity to mouse embryos. These findings show that a similar degree of caution is advisable in testing of materials contacting sperm in vitro to that which has become standard practice for culture of human embryos.

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Arthur Wisot

University of California

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David Huynh

University of California

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Gabriel Garzo

University of California

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W.B. Schoolcraft

Eastern Virginia Medical School

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Bivian Marr

University of California

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Jean Rivier

Salk Institute for Biological Studies

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Wendy Kempton

University of California

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