Don P. Wolf

Absence of an electrical polyspermy block in the mouse

To examine the possibility of an electrical polyspermy block in the mouse, we recorded the electrophysiological properties of zona-free mouse eggs during fertilization. Starting from an unfertilized value of -41 +/- 4 mV (SD), the membrane potential undergoes an oscillation (seen in 8 of 11 records) of 4 +/- 1 mV in amplitude, starting 7 +/- 5 min after insemination, and lasting about 1 min. However, except for this small oscillation, the membrane potential is constant during the 60 min following insemination; the average range (11 +/- 4 mV) is not significantly different from that which is observed in 60-min recordings from unfertilized eggs. These results indicate that the polyspermy block which is established during this period (D. P. Wolf, 1978, Dev. Biol. 64, 1-10) is not electrically mediated. Consistent with this finding, reduction of the sodium or calcium concentration in the external medium does not induce polyspermy. As a consequence of fertilization, the resistance of the egg membrane decreases from 96 +/- 34 to 44 +/- 15 M omega; this change accompanies the voltage oscillation.

Enhanced follicular recruitment in an in vitro fertilization program: clomiphene alone versus a clomiphene/human menopausal gonadotropin combination *

In an attempt to improve the pregnancy rate following in vitro fertilization and embryo transfer by increasing the numbers of embryos available for transfer to each patient, a prospective, randomized comparison of clomiphene citrate alone (50 mg/day, cycle days 5 to 9) with the combination of clomiphene as above plus human menopausal gonadotropin (2 ampules/day, cycle days 6, 8, and 10) was undertaken from January through April 1983, with 17 patients in each group. The combination produced increased follicular development, compared with clomiphene alone, resulting in the retrieval of more fertilizable oocytes. Two clinical pregnancies resulted in each group. These results show that a fixed combination of clomiphene and human menopausal gonadotropin produces a greater degree of enhanced follicular recruitment, resulting in the recovery of an increased number of fertilizable oocytes. The lack of a statistically significant increase in the number of embryos transferred per patient in the combination group as well as the identical number of clinical pregnancies in both groups suggests that this particular combination of clomiphene and human menopausal gonadotropin offers no advantage over the use of clomiphene alone for enhanced follicular recruitment.

Comparison of two clomiphene citrate dosage regimens for follicular recruitment in an in vitro fertilization program

Clomiphene citrate (CC) (150 mg/day) is used in most clinical in vitro fertilization and embryo transfer (IVF-ET) programs to induce maturation of several preovulatory follicles rather than the one characteristic of the unstimulated cycle. This study examines whether a reduced dosage of CC will induce the maturation of a similar number of follicles. The advantage of the reduced dosage should be a decrease in the dose-dependent antiestrogenic effects of CC. Normally ovulating women undergoing treatment in an IVF-ET program received CC on cycle days 5 to 9. Thirty-six patients received 150 mg/day, and 60 patients received 50 mg/day. There were no significant differences between the groups in the number or the size of follicles as measured by ultrasonography on the day of human chorionic gonadotropin administration. All seven clinical pregnancies were in the 50 mg group (P less than 0.05). These data suggest that there is no advantage to the 150 mg/day dosage of CC as compared with 50 mg/day with respect to enhanced follicular recruitment, and the higher dosage may have a detrimental effect on pregnancy establishment.

Clomiphene citrate in an in vitro fertilization program: hormonal comparisons between 50- and 150-mg daily dosages.

When clomiphene citrate is used for enhanced follicular recruitment in an in vitro fertilization and embryo transfer program, the usual dosage is 150 mg/day, although we recently reported comparable follicular development (size and number) with 50 mg/day. The present report compares circulating hormone levels between groups of patients receiving the two regimens. Gonadotropin levels were higher in the 150-mg group throughout the follicular phase. Serum estradiol (E2) levels, expressed either as total E2 or E2 per follicle greater than or equal to 15 mm, were also higher throughout the follicular phase in the 150-mg group. During the luteal phase, the progesterone levels were similar in both groups. However, there were higher E2 levels in the 150-mg group during the entire luteal phase. Even though there were no significant differences between groups with regard to the degree of enhanced follicular recruitment, there were significant differences in the observed hormone levels.

Follicular size and number in human in vitro fertilization

In an attempt to maximize the success of in vitro fertilization (IVF) and embryo transfer (ET) as a treatment for human infertility, we have examined the relationship of follicular size and number to the rates of oocyte recovery, fertilization, cleavage, and ET in clomiphene citrate-stimulated cycles. The recovery of oocytes from follicles less than 20 mm in diameter was significantly reduced over that from larger follicles, and those oocytes that were obtained from smaller follicles showed a significantly lower rate of fertilization and cleavage. In addition, the overall chance that a patient would undergo ET was greater in a cycle in which more than one follicle 20 mm or larger was developing than in a cycle in which a single large follicle was developing. This latter observation suggests that attempts at laparoscopic oocyte retrieval should be confined to cycles in which more than one accessible large follicle is developing, thereby maximizing the success rate while minimizing the risk and expense for the patient.

Human in vitro fertilization and embryo transfer

1 Historical Background and Essentials for a Program in In Vitro Fertilization and Embryo Transfer.- 2 Legal Issues Raised by In Vitro Fertilization and Embryo Transfer.- 3 Patient Screening and Selection.- 4 Hypothalamic Control of the Menstrual Cycle.- 5 Maturation of the Follicular Microenvironment.- 6 Enhanced Follicular Development with Clomiphene Citrate and Human Chorionic Gonadotropin.- 7 Human Menopausal Gonadotropins for Follicular Recruitment in In Vitro Fertilization and Embryo Transfer.- 8 Monitoring Follicular Development with Ultrasound.- 9 Monitoring Follicular Development with Estrogens.- 10 Laparoscopic Follicular Aspiration.- 11 Sperm Capacitation.- 12 Oogenesis, Fertilization and Early Development.- 13 Laboratory Details in an In Vitro Fertilization and Embryo Transfer Program.- 14 Fertility Potential Evaluation with the Zona-free Hamster Egg Bioassay.- 15 Techniques of Embryo Transfer.- 16 Implantation.- 17 Pregnancy Management Following In Vitro Fertilization and Embryo Transfer.- 18 The Clinical Coordinator in an In Vitro Fertilization and Embryo Transfer Program.- 19 Data Management in an In Vitro Fertilization and Embryo Transfer Program.- 20 Ethical Considerations in In Vitro Fertilization and Embryo Transfer.- Appendices.- Contributors.

Preliminary experince with a combination of clomiphene and variable dosages of menopausal gonadotropins for enhanced follicular recruitment

A combination of clomiphene citrate and human menopausal gonadotropin was employed for enhanced follicular recruitment in an in vitro fertilization program. All patients received 50 mg of clomiphene and 1 ampule of human menopausal gonadotropin daily from cycle day 5 through cycle day 9. Follicular monitoring was begun on day 10 using a combination of ultrasound measurement of follicular size and number and determination of peripheral estradiol levels. Based on the size and number of follicles, the peirpheral levels of estradiol, and the rate of follicular growth and increase in estradiol, human menopausal gonadotropin was continued at a dosage of 1 to 3 ampules/day through the day of human chorionic gonadotropin administration. Human chorionic gonadotropin was administered on the evening of the day the largest follicle reached or exceeded 20 mm in mean diameter if the estradiol levels had been rapidly rising or reaching a plateau and had exceeded a minimal level of 300 pg/ml. Using this protocol, 30 of 33 patients underwent laparoscopy, 29 patients had successful oocyte recovery, and 23 patients underwent embryo replacement, with the establishment of six clinical pregnancies.

Oogenesis, Fertilization and Early Development

The study of mammalian reproduction to date has led to an appreciation of some of the diverse fundamental processes and events associated with gamete maturation, fertilization and embryonic development. In this chapter, we will discuss both theoretical and practical aspects of these subjects limiting our attention to the human as much as possible.

Historical Background and Essentials for a Program in In Vitro Fertilization and Embryo Transfer

In the last 18 months, explosive growth has occurred around the world in the establishment of programs offering in vitro fertilization-embryo transfer (IVF-ET) as a treatment modality for certain types of human infertility. One of the characteristics of a rapid growth phase in the application of a relatively sophisticated new technology is a lack of standardization in approaches as well as a predominence of ancedotal accounts of results. Only now, after several years, are we beginning to see the establishment of a suitable reference base. This includes the excellent general work by R. G. Edwards entitled “Conception in the Human Female” which provides an extensive description of the endocrinology, physiology and morphology of reproductive events in the human (Edwards, 1980). Additionally, several symposia proceedings are now available (Edwards and Purdy, 1982; Beier and Lindner, 1983; Crosgnani and Rubin, 1983) which provide a great deal of useful information relating specifically to aspects of IVF-ET as conducted by individual programs. To date, however, there is not yet available a reference with sufficient detailed information from any one program to be suitable for those groups planning or establishing IVF-ET programs.