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Biomedical subjects

J F Leeton

Publications and source records attributed to J F Leeton.

At least 19 recordsLinked to original sources
PubMed1995

The regulation of assisted reproductive technology in Australia: issues and solutions.

The legislative response to assisted reproduction technology had been inappropriate and inflexible for such a rapidly developing area of medicine. A national system of regulation, consisting of a merger of components of already established committees and based on the United Kingdom system introduced in 1990, would overcome the legislative differences between States, and provide a more responsible and responsive regulatory system.

Australia↗
PubMed1992

Vaginal progesterone as luteal phase support in an IVF/GIFT programme.

To determine whether luteal phase support with vaginal progesterone could improve pregnancy rates in our IVF/GIFT programme, we performed a prospective randomised controlled study. After stimulation with clomiphene citrate/human menopausal gonadotrophin, 123 women received no luteal support and 122 received progesterone pessaries 100 mg b.d. from 48 hours prior to embryo transfer and continued throughout the luteal phase. There was no difference in the pregnancy rate following IVF/ET (6/58 and 10/58 for the pessary and control group respectively), but a significantly higher rate was noted for GIFT (13/34 and 5/42 for the pessary and control group respectively; P less than 0.05). Of interest, only one of the 19 pregnancies using luteal support was extra-uterine, compared with 6/15 in the control group.

Administration, Intravaginal↗
PubMed1990

A comparison of vaginal ultrasonic-guided and laparoscopic retrieval of oocytes for in vitro fertilization.

A retrospective analysis was undertaken to compare the less invasive technique of vaginal ultrasonic-guided oocyte retrieval with the standard laparoscopic technique. We have shown that the outcome of the transvaginal technique with respect to oocytes harvested, fertilization rate, and pregnancy rate is comparable with the laparoscopy technique. We have also shown that 9 clinicians with little previous expertise in ultrasound have been able to incorporate this technique into a busy and successful in vitro fertilization unit.

Female↗
PubMed1989

Oocyte donation: a review.

Oocyte donation provides an option for achieving pregnancy in women lacking functioning gonads, or in whom IVF techniques have failed to harvest adequate oocytes, or those who do not wish to use their own gametes because of hereditary disease. In agonadal women, artificial menstrual cycles are required before proceeding to gamete donation. A fixed cyclical steroid replacement schedule of oestradiol (E2) valerate and progesterone (P4) pessaries was initially used, but the need for synchrony between donor and recipient cycles, and the narrow window for implantation limited the transfer of fresh embryos. Donor-recipient cycle asynchrony can be overcome by using frozen-thawed embryos, or by extending the follicular phase in the recipient to widen the transfer window. Twenty-two pregnancies have now been achieved by the Monash/Epworth group, resulting in the birth of 13 healthy infants. There were no statistically significant differences in pregnancy rates (per transfer) between transfers in natural cycles (14%, four pregnancies) and steroid replacement cycles (24%, 16 pregnancies). Five pregnancies (36%) were established in women treated with 2 mg of E2 daily 13-18 days before embryo transfer with P4 starting on the day of or the day following oocyte retrieval. E2 was continued for a median of 85 days (range 49-110) and P4 for a median of 86 days (range 49-133) after the supposed last menstrual period. All but one delivery was by caesarean section. There were no perinatal deaths and no ectopic pregnancies.

Embryo Transfer↗
PubMed1987

Effect of oocyte quality and sperm characteristics on the number of spermatozoa bound to the zona pellucida of human oocytes inseminated in vitro.

Sperm characteristics and oocyte quality may play a role in in vitro fertilization. The objective of this paper is to analyze the effect of the quality of oocytes, the husband's semen characteristics, and category of the couple's infertility on the number of spermatozoa bound to the zona pellucida. One hundred eighty-one oocytes which failed to fertilize or failed to cleave were fixed in 2.5% glutaraldehyde 40 to 60 hr after insemination in vitro and examined under interference microscopy and the number of sperm bound to the zone pellucida was determined. The means +/- SD of sperm bound to mature, immature, and atretic oocytes were 51.0 +/- 50.7, 7.3 +/- 12.1 10.4 +/- 17.8, respectively. Fertilized mature oocytes (81.0 +/- 53.3) had a significantly higher number of sperm bound to zonae compared to unfertilized oocytes (41.8 +/- 47.3). It is concluded that the number of sperm bound to zonae is functionally important. The sperm motility and the number of motile sperm used to inseminate oocytes were significantly correlated with the number of sperm bound to zonae, whereas sperm morphology and sperm concentration did not correlate. This study supports the notion that sperm motility is the single most important factor influencing fertilization of human oocytes in vitro.

Female↗
PubMed1986

In-vitro fertilization and embryo transfer. Prospects of pregnancy by life-table analysis.

Data have been analysed for 1775 laparoscopies that were undertaken for the collection of oocytes, and for 1401 embryo transfers that were undertaken for the treatment of infertility by in-vitro fertilization, by the Monash University in-vitro fertilization unit team. The cumulative success rates with multiple attempts were analysed by life-table analysis and life-table graphs were constructed. Almost half the patients were pregnant after five laparoscopies. These findings suggest that treatment should consist of multiple laparoscopies and that improvements should be aimed at decreasing the morbidity, stress and cost of multiple attempts.

Actuarial Analysis↗
PubMed1986

Effect on plasma gonadotropins of cyclic steroid replacement in women with premature ovarian failure.

A sequential regimen of steroid replacement of oral estradiol valerate and progesterone (P) by intravaginal suppository was developed for women with premature ovarian failure or ovarian agenesis. The regimen, based on a 28-day cycle, resulted in peripheral plasma concentrations of estradiol and P within the normal range of the menstrual cycle and endometrial differentiation consistent with the normal secretory phase. Pregnancy has now been successfully established in four patients following this regimen of steroid treatment and transfer of donated embryos. Plasma concentrations of LH were within the normal range by the end of the first cycle of treatment with exogenous steroids. However, plasma FSH remained above the normal range, even during the third treatment cycle, consistent with the necessity of a gonadal feedback factor (inhibin?) other than estradiol and P for maintaining FSH in the normal range. Although 7/8 patients had a surge of LH at midcycle, only 3/8 patients had concomitant FSH surges, supporting a role for progesterone in facilitating the midcycle FSH surge.

Administration, Oral↗
PubMed1986

An analysis of plasma estradiol concentrations during clomiphene citrate-human menopausal gonadotropin stimulation in an in vitro fertilization-embryo transfer program.

We report here a range of plasma estradiol (E2) concentrations suitable for use in an in vitro fertilization (IVF) program. This range was derived from nonparametric analysis of plasma E2 levels using plasma E2 measurements beginning 10 days before the anticipated day of the midcycle LH surge (midpoint), as calculated from each patient's six previous menstrual cycles, during which time the patients all received the same ovarian stimulation regimen. The regimen consisted of 100 mg clomiphene citrate/day for 5 days, beginning 10 days before the anticipated midpoint, plus 150 IU human menopausal gonadotropin, commencing the day after clomiphene. A consecutive series of 102 IVF conception cycles induced in this standardized fashion were analyzed in this study. The 5th-95 percentile envelope of plasma E2 concentrations was derived as a valid clinical indicator of satisfactory folliculogenesis during IVF treatment. Five women had plasma E2 concentrations below the 5th percentile of the E2 range on at least 3 consecutive days of ovarian stimulation, while six women had E2 levels above the 95th percentile of this range on at least 3 consecutive days. This plasma E2 range defined objectively the diagnoses of ovarian hyperstimulation and inadequate stimulation in an IVF program. These criteria should help clinicians in managing ovarian responses during IVF superovulation stimulation treatment.

Clomiphene↗
PubMed1985

Oocyte and embryo donation in IVF programmes.

We have described a cyclic steroid replacement regimen of oestradiol and progesterone which is able to produce physiological concentrations of these steroids in plasma indicative of a normal menstrual cycle. The stimulation of a secretory endometrium at the appropriate time in this artificial menstrual cycle bears testament to the suitability of the treatment and has led to the establishment of pregnancy in three women with complete ovarian failure or ovarian agenesis when used in combination with the established techniques of in vitro fertilization and embryo transfer. The steroid replacement regimen can easily be adjusted to maintain pregnancy until the time of luteoplacental shift, based on the close monitoring of the plasma steroid and hCG levels in the pregnant individual. The implications of this form of treatment for other disease states and for our understanding of the mechanisms involved in ovarian hormone action, pregnancy maintenance and parturition are immense.

Chorionic Gonadotropin↗
PubMed1983

Successful use of human semen cryobanking for in vitro fertilization.

Frozen-thawed donor semen was compared with freshly ejaculated donor semen for in vitro fertilization of human oocytes in patients with infertile husbands. There was no significant difference in the fertilization rates between frozen-thawed (85%) and fresh spermatozoa (78%). Fertilization occurred with semen stored for as long as 27 months and with numbers of spermatozoa as low as 20,000/ml culture medium for insemination of oocytes. Pregnancy rates of embryos, fertilized with frozen-thawed and freshly ejaculated spermatozoa, were similar following embryo transfer.

Fertilization in Vitro↗
PubMed1983

The relationship of tubal blockage, infertility of unknown cause, suspected male infertility, and endometriosis to success of in vitro fertilization and embryo transfer.

The success of in vitro fertilization (IVF) and embryo transfer has been examined with regard to five categories of infertility over a 2-year period. Fertilization rates in vitro were highest in women with bilateral tubal blockage and women treated for endometriosis. There was a significant reduction of approximately 13% in the fertilization rate of couples with idiopathic infertility and women who had failed to conceive after 12 cycles of artificial insemination by donor. A further substantial reduction in the fertilization rate occurred when the husband had low quality semen, particularly when no abnormality was detected in the wife. Repeated IVF in couples with idiopathic infertility eventually resulted in fertilization. It is recommended that donor spermatozoa not be used for cases of idiopathic infertility, but it may be needed in cases of poor semen quality. There were no differences in the pregnancy rates following embryo replacement in any of the groups studied, nor was there any detectable effect of age on fertilization or pregnancy rates up to the age of 44 years.

Adult↗
PubMed1982

Clinical features of eight pregnancies resulting from in vitro fertilization and embryo transfer.

In vitro fertilization (IVF) and embryo transfer (ET) have resulted in the birth of nine babies, including twins. One of the twins had a congenital cardiac malformation and seven of the nine babies were girls. Labor occurred preterm in two pregnancies; and in six delivery was by cesarean section. Plasma human chorionic gonadotropin (hCG), progesterone (P), and estriol (E3) measurements and ultrasonic scans showed no obvious differences from pregnancies resulting from natural conception. Cytogenetic studies from cord blood and histologic examination of the placentas were unremarkable. The theoretic risks of pregnancy following IVF and ET are discussed. Definite conclusions cannot be drawn until a large number of babies are delivered and a long-term follow-up is completed. Initial results from the current small sample are encouraging.

Adult↗