WO2000078298A2

WO2000078298A2 - Programming ovulation by administering estrogen such as estradiol

Info

Publication number: WO2000078298A2
Application number: PCT/EP2000/005665
Authority: WO
Inventors: Dominique De Ziegler
Original assignee: Columbia Laboratories (Bermuda) Limited
Priority date: 1999-06-21
Filing date: 2000-06-20
Publication date: 2000-12-28
Also published as: CA2377609C; AU5683900A; CA2377609A1; MXPA02000127A; CO5180654A1; WO2000078298A3; PE20010640A1

Abstract

The invention relates to the use of exogenous estrogen, or a substance that causes estrogen release, in programming ovulation, measuring or controlling follicular phase length, preventing conception, facilitating fertility, therapeutically treating infertility, synchronizing early follicular phase assessments, and scheduling late follicular phase clinical evaluations.

Description

PROGRAMMING OVULATION

This application claims the benefit of United States Provisional Patent Application No. 60/139,783, filed June 21, 1999.

Field of the Invention

The present invention relates to methods of programming ovulation, measuring or controlling follicular phase length, preventing conception, facilitating fertility, treating infertility, synchronizing early follicular phase assessments, and scheduling late follicular phase clinical evaluations with exogenous estrogen or substance that causes estrogen release.

Background of the Invention

Ovulation is the process where an ovum or ova are released from the ovaries. The timing of ovulation within the menstrual cycle is critical for fertilization. Since the life span of both spermatozoa and the unfertilized ovum is limited, fertilization must take place within hours after ovulation if conception is to occur during that menstrual cycle .

The menstrual cycle can be divided into three phases on the basis of endocrine events: the follicular, the ovulatory and the luteal phases. The follicular phase extends from the first day of menses to the day before the LH surge, a massive preovulatory release of luteinizing hormone (LH, a gonadotropin) by the pituitary gland. During the first half of the luteal phase, follicle stimulating hormone (FSH, another gonadotropin) secretion increases slightly, stimulating ovarian follicular growth. Beginning one or two days after the increase in FSH levels, circulating LH levels also rise. In the second half of the follicular phase, about 7 to 8 days before the LH surge, ovarian secretion of estradiol (E₂) and estrone (Ei) increases slowly at first, then accelerates to reach a peak on the day before the LH surge. The rise in estrogen levels is accompanied by a decrease in FSH levels.

During the ovulatory phase, blood LH levels rise, culminating in the LH surge. A smaller increase in FSH secretion occurs simultaneously, but its significance is not understood. As LH levels increase, estradiol levels decrease while progesterone levels continue to increase. The LH surge, typically lasting 36 to 48 hours, leads to the final maturation of the ovarian Graafian follicle, follicular rupture and discharge of the ovum or ova from the mature Graafian follicle some 16 to 32 hours after the onset of the LH surge.

Following ovulation, during the luteal phase, the post- ovulatory ovarian follicle cells are luteinized to form a corpus luteum. A marked increase in progesterone secretion by the corpus luteum occurs during the luteal phase, along with a smaller increase in estrogen levels. As progesterone and estrogen levels increase, LH and FSH levels decline throughout most of the luteal phase. From the end of the luteal phase through the beginning of the follicular phase in the next menstrual cycle, a period referred to as the intercycle interval or luteal-follicular transition (LFT) , FSH levels rise to initiate follicular growth for the next menstrual cycle. The variability in menstrual cycle length and inability to determine its functional onset (the intercycle FSH elevation) have heretofore limited the use of the menstrual cycle in infertility treatments (Meldrum, D. et al . , "Articial Agonadism and Hormone replacement for Oocyte Donation", Fertil. Steril . (1989) 52:509-11; Steptoe, P. et al . , "Birth after the Reimplantation of a Human Embryo", Lancet (1978) 2 (8085) : 366) . The trend in the past two decades has been to adopt various surrogate approaches to avoid the complexity of menstrual cycle monitoring for assisted reproductive technology (ART) procedures, such as in vi tro fertilization (IVF), Intra Uterine Insemination (IUI) and frozen embryo transfers.

SUMMARY OF THE INVENTION The present invention provides the ability to program the menstrual cycle or natural ovulation, notably in ART procedures and/or other infertility treatments.

Specifically, the present invention relates to a method of programming ovulation in the menstrual cycle of a mammal comprising: administering to the mammal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to duplicate luteal-phase levels of estrogen. The present invention further relates to a method of programming ovulation in the menstrual cycle of a mammal to fall on a preset date comprising:

(i) selecting a preset date; and (ii) administering to, the mammal exogenous estrogen or a substance that causes estrogen release in a dosing regimen effective to cause ovulation to occur on the preset date.

The present invention also relates to a method of measuring or controlling follicular phase length in a mammal comprising:

(i) administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release; and (ii) calculating the interval between the mammal's intercycle FSH and LH surge. In addition, the present invention relates to a method of preventing conception in a mammal comprising: administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release .

The present invention further relates to a method of facilitating fertility in a mammal, comprising: administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release .

The present invention also relates to a method of treating infertility in a mammal, comprising: administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release .

In addition, the present invention relates to a method of synchronizing an early follicular phase assessment to the functional onset of follicular phase in a mammal, comprising: (i) selecting a preset date for performing the early follicular phase assessment; and (ii) administering to the mammal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to cause intercycle FSH elevation to occur on the preset date. Finally, the present invention relates to a method of scheduling a late follicular phase clinical evaluation in a mammal, comprising:

(i) selecting a preset date for performing the late follicular phase clinical evaluation; and (ii) administering to the mammal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to cause LH surge to occur at least one day after the preset date.

DETAILED DESCRIPTION OF THE INVENTION

Definitions "Effective amount" refers to the amount required to produce the desired effect.

"Effective dosing regimen" refers to the timing, sequence, route and dosage of drug delivery required to produce the desired effect.

"Animal" refers to a living organism having sensation and the power of voluntary movement, and which requires for its existence oxygen and organic food. Examples include, without limitation, members of the human, equine, porcine, bovine, murine , canine, or feline species. In the case of a human, an "animal" may also be referred to as a "patient" .

"Mammal" refers to a warm-blooded vertebrate animal.

"Facilitating fertility" includes, without limitation, increasing the rate of conception or improving fertility in an animal .

"Treating infertility" includes, without limitation, alleviating infertility, increasing the rate of conception or improving fertility in an animal with decreased or impaired fertility or proven infertility.

"Preventing conception" includes, without limitation, reducing the rate of conception and/or facilitating or improving the efficacy of contraception in an animal.

"Contraception" includes any drug, technique or device for preventing conception or impregnation. Examples include, without limitation, barrier contraceptives, oral contraceptives and natural planning methods (periodic abstinence) such as the calendar rhythm and symptothermal methods .

Methods of the Present Invention

Studies have shown that exogenous E₂ can regulate intercycle FSH levels. De Ziegler, D. et al . , "Controlled Preparation of the Endometrium with Exogenous Estradiol and Progesterone in Women Having Functioning Ovaries", Fertil . Steπl . (1991) 56:851-5, demonstrated that physiological amounts of exogenous E₂ inhibit follicular recruitment and growth for up to 2 weeks after the onset of the last menstrual period. Le Nestour, E. et al . , "Role of Estradiol m the Rise m Follicle-Stimulating Hormone Levels during the Luteal-Follicular Transition", J. Clin . Endocπnol . Metab . (1993) 77:439-42, showed that the inhibition of follicular recruitment results from an inhibition of intercycle FSH rise by exogenous E₂. In the latter study, exogenous E₂ started on day 25 of the previous cycle delayed the intercycle FSH rise until after E₂ treatment was discontinued. After interrupting E₂ treatment, the plasma FSH increment was of similar amplitude than that observed in control (untreated) cycles. The acme of FSH rise occurred 3 days after E₂ treatment was stopped This study also confirmed that administrating E₂ during the luteal phase did not prevent the normal occurrence of menses. Therefore, at the end of the luteal phase, bleeding is triggered by the decrease m progesterone independently of plasma E₂ concentration (De Ziegler, D. et al . , "Suppression of the Ovary Using a GnRH Agonist Prior to Stimulation for Oocyte Retrieval", Fertαl . Steπl . (1987) 48-807-10). The present invention provides methods of using exogenous estrogen or a substance that causes release of estrogen to program ovulation or onset of new menstrual cycles, and to measure the true duration of follicular phase (intercycle FSH elevation - LH surge interval) .

Specifically, the present invention relates to a method of programming ovulation in the menstrual cycle of an animal comprising: administering to the animal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to duplicate luteal-phase levels of estrogen.

The present invention further relates to a method of programming ovulation in the menstrual cycle of an animal to fall on a preset date comprising:

(i) selecting a preset date; and

(ii) administering to the animal exogenous estrogen or a substance that causes estrogen release in a dosing regimen effective to cause ovulation to occur on the preset date.

Without being bound to any mechanism of action, the inventive methods are believed to program ovulation or the onset of new menstrual cycles by controlling intercycle FSH elevation. The inventive methods offer a simple means for timing clinical evaluations and/or treatments such as PCT's,

IVF' s or IUI's in the menstrual cycle, and the ability to use the menstrual cycle or natural ovulation for ART procedures . In particular, the inventive methods can be used to prime endometrial receptivity for frozen embryo transfers by administering exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to prevent follicular recruitment. Preferably, the dosing regimen duplicates luteal-phase levels of estrogen. More preferably, the methods further comprise administering an effective amount of progesterone after administering the estrogen or substance that causes estrogen release.

In addition, the inventive methods can be used to synchronize early follicular phase assessments, including baseline ultrasound, FSH, inhibin and E₂ measurements, to the functional onset of the follicular phase (the intercycle FSH elevation) . Furthermore, the inventive methods can be used to schedule clinical evaluations of the late follicular phase, including PCT's and utero-tubal contractility assessments .

The present invention also relates to a method of measuring or controlling follicular phase length in an animal comprising:

(i) administering to the animal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release; and (ii) calculating the interval between the mammal's intercycle FSH and LH surge. The follicular phase length (time interval from intercycle FSH rise to LH surge) is a potentially important parameter of ovarian function. By measuring the follicular phase length, the inventive methods can be used to predict reproductive potential and/or diagnose menstrual abnormalities, ovulatory dysfunctions and menopause. By controlling follicular phase length, the inventive methods can be used to induce, stimulate or inhibit ovulation.

Ovulation induction and/or stimulation can be useful in facilitating fertility and treating infertility, particularly ovulatory dysfunctions including, without limitation, polycystic ovary syndrome, chronic anovulation, hypothalamic amenorrhea and luteal phase deficiency. Thus, the present invention further relates to a method of facilitating contraception or treating infertility in an animal, comprising: administering to the animal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release.

Conversely, ovulation inhibition can prevent conception and be beneficial as a contraceptive. Thus, the present invention further relates to a method of preventing conception in an animal comprising: administering to the animal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release . The inventive method may be used in conjunction with other forms of contraception, including natural family planning methods which require abstinence from coitus during fertile periods. The instant invention may substantially improve the reliability of predicting the timing of peak fertile periods.

The animal is preferably a mammal, more preferably a human having a menstrual cycle varying from 25-35 days.

The exogenous estrogens used in the inventive methods include, without limitation, biogenic estrogens (e.g., estradiol, estrone, estriol) , synthetic estrogens (e.g., EE or mestranol) and other estrogens known in the art. A preferred exogenous estrogen is estradiol valerate (E₂ valerate) .

The estrogen or substance that causes estrogen release may be administered by any means known to a person of ordinary skill in the art. For example, the estrogen or substance that causes estrogen release may be administered by a single dose, multiple discrete doses or continuous infusion. The specific dose level for any particular patient will vary depending upon a variety of factors, including the activity and the possible toxicity of the specific compound employed; the age, body weight, general health, sex and diet of the patient; the time of administration; the rate of excretion; drug combination; the severity of the particular disease being treated; and the form of administration.

For the methods of the present invention, any dosing regimen known to a person of ordinary skill for regulating the timing, sequence, route and dosage of drug delivery can be used and repeated as necessary to effect treatment. Such regimen may include pretreatment and/or co-administration with one or more additional therapeutic agent (s) either (i) together in a single formulation, or (ii) separately in individual formulations designed for optimal release rates of their respective active agent. EX7AMPLE

The following example is illustrative of the present invention and is not intended to be a limitation thereon.

EXAMPLE 1

The feasibility and reliability of advance programming of ovulation in the menstrual cycle was determined, and the extent of fluctuations in follicular phase length was assessed by measuring the true follicular phase length (time interval from intercycle FSH rise to LH surge) in women whose menstrual cycles normally ranged from 25 to 35 days.

MATERIAL AND METHODS Population and Treatment Women undergoing infertility evaluations, whose menstrual cycle normally lasted 25 to 35 days, used an E₂ based approach to pre-program post-coital tests (PCT) , baseline and peri-ovulatory ovarian ultrasounds and/or other procedures needed for their infertility work-up. De Ziegler, D. et al., "Controlled Preparation of the Endometrium with Exogenous Estradiol and Progesterone in Women Having Functioning Ovaries", Fertil . Steril . (1991) 56:851-5; De Ziegler, D. et al . , "Synchronization of Endogenous and Exogenous FSH Stimuli in Controlled Ovarian Hyperstimulation (COH) " , Hum. Reprod . (1998) 13; 561-4; Lelaidier, C. et al . , "Controlled Preparation of the Endometrium with Estradiol and Progesterone: a Novel Regimen Not Using a Gonadotropin-releasing Hormone Agonist", Hum . Reprod . (1992) 7:1353-6.

Treatment with exogenous E₂ was initiated on the earlier of (i) day 25 of the previous menstrual cycle or (ii) approximately 3-5 days before the anticipated menses. The women took 2 mg of E₂ valerate (Progynova; Schering Pharmaceuticals, Berlin, Germany) twice daily until the first Saturday after the onset of menses. In two instances, E₂ treatment was extended 1 more week until the second Saturday after menses for reasons of personal convenience. The last day of E₂ treatment was arbitrarily called FDO (functional day 0) and served as reference for numbering days in the follicular phase from FD1 onward. Women were informed that if they were already pregnant, no risk of malformation existed as E₂ valerate is commonly prescribed to pregnant women.

Ultrasound assessment and hormone measurements

A baseline vaginal ultrasound was performed on FDO. The three largest diameters of each ovary were measured and the ovarian volume was calculated using the conventional formula, volume = τc/6 (DjxD₂xD₃) , where D represents the maximum diameter of the ovary in three perpendicular planes (Frydman, R., "A Protocol for Satisfying the Ethical Issues Raised by Oocyte Donation: the Free, Anonymous, and Fertile donors", Fertil . Steril . (1990) 53:666-72). Ovarian volumes were sorted into "largest" and "smallest". It was assumed that the smaller ovarian volume represented the ovary not carrying the previous corpus luteum (Kyei-Mensah, A. , "Transvaginal Three-dimensional Ultrasound: Accuracy of Follicular Volume Measurements, Fertil . Steril . (1996) 65:371-6) . Ovarian follicles were evaluated and follicles > 10 mm were measured and reported.

Vaginal ultrasound was repeated on FD13. Follicles > 10 mm were measured and described. On FD13 , follicles _> 16 were considered "ovulatory" and were counted. In addition, the amount of cervical mucus was assessed and graded from + to +++ : + indicated some sonoluscent mucus identifiable in the cervical canal; +++ was recorded when the entire length of the cervical canal was markedly dilated by sono- transparent mucus; ++ represented intermediary results. Any fluid in the cul-de-sac was identified and reported. Plasma FSH, LH and E₂ were measured on FDO, FD3 and FD9.

Plasma LH, E₂ and P were measured on FD13. FSH and LH increments in response to E₂ withdrawal from FDO to FD3 were calculated and expressed as ΔFΞH and ΔLH, respectively.

Plasma FSH and LH were measured using solid-phase immunoassay kits (Chiron Diagnostics Corporation, Norwood, MA, USA) . The intraassay and interassay coefficients of variation (CV) were 2.8% and 4.9% for FSH, and 4.7% and 5.0% for LH, respectively.

Data Analysis and Statistics

Patients were divided into three groups based on findings on FD13. On FD13 , LH levels that were 2 SD higher than mean values obtained in all patients from FDO through FD9 were considered to reflect an LH surge. Group A consisted of women who had evidence of an LH surge on FD13. Group B consisted of women without evidence of LH surge on FD13 but with signs of previous ovulation. Group C had no LH surge and no evidence of previous ovulation on FD13. Because of the small number of women in groups B and C, comparisons between groups were solely descriptive. In group A, indices observed on FDO, FD3 , FD9 and FD13 were compared by analysis of variance (ANOVA) . Variables on FDO and FD3 were also compared in the whole population using paired statistics.

RESULTS Demographics, menstrual cycle information and baseline ultrasound data appear in Table I. Table I also shows treatment information such as the duration between the onset of menses and end of E₂ treatment (FDO) (duration of FSH suppression by E₂) . Hormone levels and ultrasound findings on FDO, FD3 , FD9 and FD13 appear in Table II. The results were sorted according to whether evidence was obtained of preovulatory LH surge (ovulation) (group A) , previous ovulation (group B) , or no ovulation (group C) on FD13. As shown in Table II, 19 of 26 women (73%) had a preovulatory LH surge on FD13. In these women, the LH level reached 51.7 ± 5.3 mlU/ L (mean ± SEM) . All had one preovulatory follicle on FD13 and an excellent mucus score (+++) . Endometrial thickness ranged from 6.6 to 12 mm. There was evidence of previous ovulation (group B) in 4 (15%) of 26 women (group B) . LH levels were low (mean, 9.8 mlU/ml ; range, 5-12.2 mlU/mL) , no ovulatory follicles were seen and progesterone (P) levels (group B) were elevated. In these women, plasma P levels reached 11.5 (range, 6.8-15 nmol/L) as compared with 3.1 + 0.8 nmol/L in those who had an LH surge on FD13. The mucus score was ++ or less in all 4 women. It was concluded that these 4 women had already ovulated . As shown in Table I, women who had already ovulated on FD13 (n=4) were older (mean, 39 years; range, 37-44 years) and had a higher FSH increment in response to E₂ withdrawal

(mean ΔFSH 4.9 mlU/ml ; range, 3-6.5 mlU/mL) . By comparison, the mean age of the ovulatory population was 34.7 + 2 years and ΔFSH was 3.1 ± 0.8 mlU/mL (Table II). On FD9 , hormonal profiles appeared similar in groups A and B. On FD13, however, plasma E₂ had dropped from values on FD9 (mean, 745; range, 614-1021 pmol/L) in all four women who ovulated early. In contrast, in women who had an LH surge on FD13 , E₂ increased further from 610 ± 95 pmol/L (mean ± SEM) on FD9 to 1008 ± 88 pmol/L on FD13.

In the remaining three patients (12%) , there was no evidence of imminent or past ovulation (group C) . On FD9, plasma E₂ levels were lower in these three women (mean, 91; range, 74-107 pmol/L) than in those who ovulated either on FD13 (group A; 610 ± 95 pmol/L) or before FD13 (group B; mean, 745 pmol/L; range, 614-1021 pmol/L) . The interval between the onset of menses and the end of E₂ treatment (FDO) varied from 1 to 12 days because E₂ treatment was arbitrarily discontinued on a set day of the week (first or sometimes second Saturday after menses) . The treatment was designed to program preovulatory testing (e.g., post-coital test) on a Friday. The interval from menses to the end of E₂ treatment was not different (certainly not longer) in women who had a short follicular phase (mean, 3.5 days; range, 1-6 days) as compared with the rest of the population (mean ± SEM, 4.9 ± 2.5 days; range, 1-12 days) . Baseline ultrasounds on FDO showed no evidence of follicular growth (follicle > 10 mm) in all the participating women.

These two findings indicate that early ovulation did not result from an elevation of FSH levels during E₂ treatment (escape) , which would have prematurely induced follicular growth. The FSH/LH ratio showed a strong correlation between values found on FDO and FD3 (P < .001) .

This indicates that E₂ does not affect the FSH/LH ratio in intact women in the early follicular phase. An inverse correlation was noted between their FSH/LH ratio on FDO and baseline ovarian volume (P < .05) . TABLE I

Demographics, Baseline Ultrasound, and Treatment Data for 26 Infertile Patients Undergoing Ovulation Evaluations and Post- Coital Tests

Study Group

Patients with Patients with

LH surge on a short functional day follicular

13 phase Anovulatory

Variable (n = 19) (n = 4) patients

(n = 3)

Age (y) 34.7±2 39 (34-44) 29.7 (28-33)

Cycle length 29.2±0.7 26.7 (25-28) 34.6 (34-35) (d)

Ovarian volume (cm Largest 7.111.0 9.511.6 8.2 (12.9-3.6; Smallest 2.8±0.4 4.2±1.0 3.2 (6.6-2.1)

Menses to end 4.912.5 (1-12; 3.5 (1-6) 3 (1-7) of E₂

(Functional day 0)

Note All values are means (range) or means ± SEM (range] TABLE II

Hormone Data for 26 Infertile Patients Undergoing Ovulation Evaluations and Post-Coital Tests

Study group

Patients with

Patients with ^a short Anovulatory

LH surge on follicular patients

FD13 (n = 19) phase (n = 4) _{(n = 3)}

Functional day 0

FSH level 5.5±0.6 7.0 (4.2-10.7) 3.3 (0.7-4.5)

(mlU/mL)

LH level (mlU/mL) 5.5±1 5.0 (2-8.4) 2.8 (1.5-4)

FSH/LH 1.3±0.3 1.4 1.2

E₂ level (pmol/L) 462±55 349 (186-473) 389 (97-568)

Functional day 3

FSH level 5.6±0.7* 11.9 (6.2-15.1) 5.1 (2.9-7.6) (mlU/mL)

LH level (mlU/mL) 7.0±0.6* 9.4 (4.0-15.3) 4.8 (3.6-5.5)

FSH/LH 1.3±0.2 1.3 1.1

E₂ level (pmol/L) 160±27* 137 (74-226) 125 (74-218)

Functional day 3 -functional day 0

ΔFSH level (mlU/mL) 3.1±0.8 4.9 (3-6.5) 1.4 (1-2)

ΔE₂ level (pmol/L) -302±55 -212 -264

Functional day 9

FSH level 4.4±0.6 4.6 (2.2-8.1) 9 (3.1-4.9)

LH level (mlU/mL) 5.8±0.7 7.1 (6-10.1) 4.8 (3.4-6.6)

E₂ level (pmol/L) 610±95» 745 (614-1021) 91 (74-107) Study group

Patients with

Patients with a short Anovulatory

LH surge on follicular patients FD13 (n = 19) phase (n = 4) (n = 3)

Functional day 13

LH level 51.7±5.3 9.8 (5-12.2) 8.6 (6.2-10.4)

E₂ level (pmol/L) 1008+88V 214 (86-367) 98.3 (79-137)

P level (nmol/L) 3. l±O .8 11.5 (6.8-15) 1.3 (1.1-2)

Note : All values are means ± SEM (range) .

* different from FDO (baseline), P < .01

• different from FD3 , P < .01 or means

V different from FD9, P < .01

DISCUSSION More than 70% of women whose menstrual cycle usually lasted from 25-35 days had an LH surge and other preovulatory characteristics precisely 13 days after the onset of the intercycle FSH rise. The latter signal was initiated by interrupting the E₂ treatment started in the late luteal phase, as described previously (Le Nestour, E. et al , supra . ) . Because E₂ was arbitrarily interrupted on a Saturday, the preovulatory LH surge occurred 13 days later on a Friday in all these women.

This study confirms the feasibility and practicality of programming ovulation in the menstrual cycle with exogenous E₂ given at doses that duplicate luteal phase levels. With this original yet simple approach, it appears possible to schedule ovulation to occur on a preset date in most women, particularly women whose menstrual cycles normally vary from 25 to 35 days. Four of the seven women who did not have an LH surge on FD13 had a truly short follicular phase, with an interval of < 13 days between intercycle FSH elevation and the LH surge .

The data also confirms that the apparent variability in follicular phase length results mainly from variability in the timing of intercycle FSH elevation. In > 70% of women, the follicular phase length, when properly measured by determining the time interval from intercycle FSH rise to LH surge, was as constant as the luteal phase. In contrast, four of the seven women whose plasma LH levels were low on FD13 showed evidence that ovulation had already occurred. These women had truly short follicular phases. On FD13 , none of them showed follicles > 12mm, fluid was identified in the cul-de-sac, plasma P levels were elevated and plasma E₂ had dropped profoundly compared with values on FD9.

The possibility of an escape from the suppressing effects of E₂ on FSH can be safely ruled out in these women by the absence of any developing follicle (> 10 mm) at the end of E₂ treatment (FDO) . Furthermore, the interval between the onset of menses and the end of E₂ treatment was not different (if anything, it was shorter) in these four women. The four women who ovulated early were older (mean, 39 years; range, 34-44 years) than the rest of the population (mean ± SEM, 34.7 ± 2) . The amplitude of the FSH rise in response to E₂ withdrawal

(ΔFSH) was higher (mean, 4.9; range, 3-6.5 mlU/mL) than

in the rest of the population, in whom mean ΔFSH was 3.1 + 0.8 mlU/mL (mean ± SEM) . Of the women with early ovulation, three subsequently underwent controlled ovarian hyperstimulation (COH) . All showed poor ovarian response, with hMG needs that were higher than normal. This observation is in agreement with the concept that early follicular development previously identified by elevated early follicular phase E₂ levels reflects an aging-related alteration of the ovarian function (Edwards, R. et al., "Time to Revolutionize Ovarian Stimulation", Hum . Reprod. (1996) 11:917-9). Burger, H. et al., "The Endocrinology of the Menopausal Transition: a Cross-sectional Study of a Population-based Sample", J. Clin . Endocrinol . Metab . (1995) 80:3537-45, showed a decrease in the production of inhibin by developing follicles in older women. During the menstrual cycle, insufficient protein production (inhibin A and/or other substances) by the developing follicle of aging women may result in earlier LH surges triggered by lower E₂ levels. The results indicate that it is possible to measure the true follicular phase length (intercycle FSH rise to LH surge interval) . The finding of a 15% incidence of short follicular phase is in agreement with the incidences most commonly quoted for short or inadequate luteal phase.

The remaining three women with low LH values and no ovulatory follicle on FD13 also had low P levels, indicating they had not ovulated. In these three women, the amplitude of the FSH signal in response to E₂ withdrawal, or ΔFSH, was 1.0, 1.1 and 2.1 mlU/mL, respectively. These values were lower than those seen in women who had an ovulatory response on FD13 and in whom ΔFSH was 3.1 ± 0.8 mlU/mL (mean ± SEM). In these three women, the smaller increase in FSH triggered by E₂ withdrawal appeared to be insufficient to initiate follicular growth. The usual menstrual cycle length was 34, 35 and 35 days, respectively, in these three patients, findings that are at the higher end of the 25- 35 day limit. Hence, women whose menstrual cycles are naturally long appear more likely to have minimal intercycle FSH signals in response to E₂ withdrawal, a phenomenon possibly instrumental to their tendency for long menstrual cycles.

The nature of the mechanism (s) controlling the amplitude of ΔFSH initiated by E₂ withdrawal remains

elusive. At one end of the spectrum, ΔFSH correlates negatively with age (P < .05) and tends to be increased in women whose follicular phases are shorter or whose reproductive potential is compromised. However, the values observed in early ovulators overlap with those observed in women who ovulate normally. This is in agreement with Schipper, I. et al . , "Lack of Correlation between Maximum Early Follicular Phase Serum Follicle Stimulating Hormone Concentrations and Menstrual Cycle Characteristics in Women under the Age of 35 Years, Hum . Reprod . (1998) 13:1442-48, who showed that early follicular FSH values did not correlate with menstrual cycle characteristics in women < 35 years of age. At the other end of the spectrum, ΔFSH is reduced in women whose menstrual cycles are longer than normal. Clarifying the mechanisms that control the amplitude of FSH increments in response to end-luteal decrease in E₂ may be crucial for understanding both ovarian aging and oligo- anovula ion. Any and all publications, patents and patent applications mentioned in this specification are indicative of the level of skill of those skill in the art to which this invention pertains. All such publications, patents and patent applications are herein incorporated by reference as though set forth herein in full, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference. The invention being thus described, it will be apparent to those skilled in the art that the same may be varied in many ways without departing from the spirit and scope of the invention. Such variations are included within the scope of the appended claims.

Claims

What is claimed is:

1. A method of programming ovulation in the menstrual cycle of a mammal comprising: administering to the mammal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to duplicate luteal-phase levels of estrogen.

2. The method of claim 1, wherein the exogenous estrogen is estradiol.

3. The method of claim 1, wherein the mammal is a human .

4. The method of claim 3, wherein the human has a menstrual cycle varying from 25-35 days.

5. A method of programming ovulation in the menstrual cycle of a mammal to fall on a preset date comprising:

(i) selecting a preset date; and

(ii) administering to the mammal exogenous estrogen or a substance that causes estrogen release in a dosing regimen effective to cause ovulation to occur on the preset date.

6. The method of claim 5, wherein the mammal is a human .

7. The method of claim 6, wherein the human has a menstrual cycle varying from 25-35 days.

8. A method of measuring or controlling follicular- phase length in a mammal comprising:

(i) administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release; and

(ii) calculating the interval between the mammal's intercycle FSH and LH surge.

9. The method of claim 8, wherein the exogenous estrogen is estradiol.

10. The method of claim 8, wherein the mammal is a human .

11. The method of claim 10, wherein the human has a menstrual cycle varying from 25-35 days.

12. A method of preventing conception in a mammal comprising: administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release.

13. The method of claim 12, wherein the exogenous estrogen is estradiol.

14. The method of claim 12, wherein the mammal is a human .

15. The method of claim 14, wherein the human has a menstrual cycle varying from 25-35 days.

16. The method of claim 14, wherein the human abstains from coitus during fertile periods.

17. A method of facilitating fertility in a mammal, comprising: administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release.

18. The method of claim 17, wherein the exogenous estrogen is E₂ valerate.

19. The method of claim 17, wherein the mammal is a human .

20. The method of claim 19, wherein the human has a menstrual cycle varying from 25-35 days.

21. A method of treating infertility in a mammal, comprising: administering to the mammal an effective dosing regimen of exogenous estrogen or a substance that causes estrogen release.

22. The method of claim 21, wherein the exogenous estrogen is estradiol.

23. The method of claim 21, wherein the mammal is a human.

24. The method of claim 23, wherein the human has a menstrual cycle varying from 25-35 days.

25. A method of synchronizing an early follicular phase assessment to the functional onset of follicular phase in a mammal, comprising:

(i) selecting a preset date for performing the early follicular phase assessment; (ii) administering to the mammal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to cause intercycle FSH elevation to occur on the preset date.

26. The method of claim 25, wherein the early follicular phase assessment is selected from the group consisting of baseline ultrasound, FSH, inhibin and E₂ measurements .

27. A method of scheduling a late follicular phase clinical evaluation in a mammal, comprising: (i) selecting a preset date for performing the late follicular phase clinical evaluation;

(ii) administering to the mammal exogenous estrogen, or a substance that causes estrogen release, in a dosing regimen effective to cause LH surge to occur at least one day after the preset date.

28. The method of claim 27, wherein the mammal is a human .

29. The method of claim 28, wherein the human has a menstrual cycle varying from 25-35 days.

30. The method of claim 27, wherein the late follicular phase clinical evaluation is selected from the group consisting of PCT and utero-tubal contractility assessment . manufacture of a medicament for the therapeutic treatment of infertility in a mammal.

32. Use according to claim 31 wherein the medicament is for administration in a dosing regimen effective to prevent follicular recruitment.

33. Use according to claim 31 wherein the medicament is for administration in a dosing regimen effectctive to duplicate luteal phase levels of estrogen.

34. Use according to any one of claims 31 to 33 wherein the infertility is caused by, or associated with, polycystic ovary syndrome, chronic anovulation, hypothalamic amenorrhea or luteal phase deficiency.

35. Use according to any one of claims 31 to 34 wherein the medicament is for administration prior to an administration of progesterone.

36. Use according to any one of claims 31 to 35 wherein the estrogen is estradiol.

37. Use according to any one of claims 31 to 35 wherein the estrogen is E₂ valerate.