Novel clomiphene "stair-step" protocol reduces time to ovulation in women with polycystic ovarian syndrome

Comparing efficacy and safety of stair step protocols for clomiphene citrate and letrozole in ovulation induction for women with polycystic ovary syndrome (PCOS): a randomized controlled clinical trial

Polycystic ovary syndrome (PCOS) is characterized by menstrual irregularities, high androgen levels, and ovarian cysts. Clomiphene citrate (Clomid) and letrozole have both been investigated as ovulation induction therapies for PCOS. This interventional study aimed to compare the efficacy and safety of a stairstep practice of letrozole versus clomiphene citrate in women with PCOS. A total of 100 women diagnosed with PCOS and infertility participated in the study, which took place from March 2021 to July 2022 at the Maternity and Children Teaching Hospital in Adiwaniyah Province, Iraq. Participants were randomly assigned to one of two groups (each with 50 women): the first group received clomiphene citrate in a stair step pattern (single dose of 50 mg, 100 mg, and 150 mg) for five days, for a maximum of three cycles; the second group received letrozole in a stair step pattern (single dose of 2.5, 5, and 7.5 mg) for five days, for a maximum of three cycles. Follicle size was monitored using ultrasound to achieve a follicle size >18 mm. The ovulation rate was higher in the letrozole group (86.0%) compared to the clomiphene citrate group (72.0%), although the difference was not statistically significant (p=0.086). The pregnancy rate was slightly higher in the letrozole group (22.0% vs 18.0%), but also not statistically significant (p=0.617). However, the mean time from menstruation to ovulation was significantly shorter in the letrozole group (17.20±1.32 days) compared to the clomiphene citrate group (24.08 ± 1.56 days, p<0.001). There were no significant differences in common side effects between the two groups. Overall, letrozole was found to be as safe as clomiphene citrate but demonstrated a shorter time to ovulation. Further studies with larger sample sizes are necessary to validate these findings and determine their clinical implications.

Ovulation induction techniques in women with polycystic ovary syndrome

Anovulation is very common and has several different clinical manifestations, including amenorrhea, oligomenorrhea and abnormal uterine bleeding. Various mechanisms can cause anovulation. The clinical consequences and commonest chronic anovulatory disorder, polycystic ovary syndrome (PCOS), has a prevalence that ranges between 6 to 10% of the global population. While multiple causes can eventually result in PCOS, various methods have been described in the literature for its management, often without ascertaining the underlying cause. Ovulation Induction (OI) is a group of techniques that is used in women with PCOS who are looking to conceive and are unbale to do so with natural means. This narrative review presents a summary of the current evidence and available techniques for OI in women with PCOS, highlighting their performance and applicability.

Ovarian Drilling: Back to the Future

Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility. The complex metabolic dysregulation at the base of this syndrome often renders infertility management challenging. Many pharmacological strategies have been applied for the induction of ovulation with a non-negligible rate of severe complications such as ovarian hyperstimulation syndrome and multiple pregnancies. Ovarian drilling (OD) is currently being adopted as a second-line treatment, to be performed in case of medical therapy. Laparoscopic ovarian drilling (LOD), the contemporary version of ovarian wedge resection, is considered effective for gonadotropins in terms of live birth rates, but without the risks of iatrogenic complications in gonadotropin therapy. Its endocrinal effects are longer lasting and, after the accomplishment of this procedure, ovarian responsiveness to successive ovulation induction agents is enhanced. Traditional LOD, however, is burdened by the potential risks of iatrogenic adhesions and decreased ovarian reserve and, therefore, should only be considered in selected cases. To overcome these limits, novel tailored and mini-invasive approaches, which are still waiting for wide acceptance, have been introduced, although their role is still not well-clarified and none of them have provided enough evidence in terms of efficacy and safety.

Endometrial and follicular development following stair-step and traditional protocols in women with polycystic ovary syndrome: An RCT

Background

Various strategies have been proposed for polycystic ovary syndrome (PCOS) treatment.

Objective

To investigate and compare the number and size of ovarian follicles, endometrial thickness, and ovulation rate by traditional protocol (TP) and stair-step protocol (SSP).

Materials and Methods

Sixty infertile PCOS women were allocated into two groups (SSP = 30 and control TP = 30) between May and October 2019 in the Besat Hospital, Sanandaj, Iran. In the SSP group, the infertile women were treated with 50 mg/daily clomiphene citrate (CC) for five days, while the nonresponsive women were prescribed 100 mg daily CC for five days in the same cycle. The maximum dose (150 mg) was administered until ovulation occurred. In the control group, in non-ovulatory cases, the dose was increased in the next cycle. Ultrasound was used to detect ovulation.

Results

Endometrial thickness changes with various doses of CC were significantly different in the TP. The comparison of both protocols showed a significant difference in endometrial thickness only at 50 mg CC. The number of follicles in the left ovary was significantly different in both protocols at 150-mg CC. The size of ovarian follicles in the left ovary was significantly different between the two protocols at 100-mg CC. The ovulation rate was significantly different in the SSP at 100- and 150-mg doses of CC. Moreover, 86% of ovulation occurred at 100-mg CC in the SSP, while this rate was 73% in the TP.

Conclusion

The most appropriate dose for ovulation in patients with PCOS is 100 mg CC.

Comparison of the efficacy of letrozole stair-step protocol with clomiphene citrate stair-step protocol in the management of clomiphene citrate-resistant polycystic ovary syndrome patients

PURPOSE

We sought to compare the efficacy of the letrozole (LTZ) stair-step protocol with clomiphene citrate (CC) stair-step protocol in the management of 150 mg dose of CC-resistant polycystic ovary syndrome (PCOS) patients.

METHODS

We retrospectively compared a total of 61 patients diagnosed as being resistant to the traditional CC protocol who were subsequently managed using the LTZ stair-step protocol with CC-resistant 56 patients who were treated with CC stair-step protocol. The number of follicles ≥18 mm, endometrial thickness, time to ovulation, clinical pregnancy rates, multiple pregnancy rates, spontaneous abortion rates, live birth rates, and systemic side effects in patients were evaluated.

RESULTS

The mean time to ovulation was significantly shorter in the LTZ stair-step group than the CC stair-step group (17.3 ± 7.7 and 22.4 ± 8.1 days, respectively, p < 0.001). The ovulation rate was significantly higher in patients treated with LTZ stair-step protocol than those treated with the CC stair-step protocol (83.6% and 64.2%, respectively, p = 0.007). The clinical pregnancy rate was higher in the LTZ stair-step than the CC stair-step group (32.7% and 17.8%, respectively, p = 0.015). LTZ stair-step group had a significantly higher live birth rate than that of the CC stair-step group (27.8% and 14.2%, respectively, p = 0.012).

CONCLUSION

The LTZ stair-step protocol revealed higher ovulation, clinical pregnancy, and live birth rates with a shorter time to achieve ovulation than the CC stair-step protocol. Increment of the dose in the same cycle in both protocols did not cause any additional severe side effects.

Pregnancy outcomes following different protocols of controlled ovarian hyperstimulation in couples undergoing intrauterine insemination

Clomiphene citrate (CC), letrozole and cetrorelix acetate are frequently used agents in controlled ovarian hyperstimulation (COH). However, these three agents have not yet been compared to one another regarding their pregnancy outcomes. The present study was designed to retrospectively compare pregnancy outcomes among the three aforementioned agents. This study involved infertile couples with an infertility duration of at least 2 years, ages 18 to 42 years and who were referred to have their first intrauterine insemination (IUI) treatment cycle. All patients underwent COH with recombinant follicle-stimulating hormone (rFSH) plus CC (n = 118), letrozole (n = 81), or cetrorelix acetate (n = 62), followed by IUI. Using the one-way multivariate analysis of covariance to control female patients' ages, patients stimulated with cetrorelix acetate/rFSH or CC/rFSH had higher numbers of preovulatory follicles than women stimulated with letrozole/rFSH (P < .02), whereas women stimulated with cetrorelix acetate/rFSH had a thicker endometrium than women stimulated with CC/rFSH (P < .0005). Biochemical pregnancy rates were similar among the three protocols of COH. However, women stimulated with letrozole/rFSH showed clinical pregnancy rates higher than those stimulated with CC/rFSH (P = .003) or cetrorelix acetate/rFSH (P = .03) and subclinical abortion rates lower than those stimulated with CC/rFSH or cetrorelix acetate/rFSH (P = .009). Of the different protocols of COH, the odds of having a clinical pregnancy was 3.1 times greater for women stimulated with letrozole/rFSH than women stimulated with CC/rFSH (P = .004) and 2.8 times greater for women stimulated with letrozole/rFSH than women stimulated with cetrorelix acetate/rFSH (P = .03). Our observations show that increased numbers of preovulatory follicles or endometrium thickness do not necessarily improve pregnancy outcomes, because pregnancy outcomes are also subjected to the type of COH used agent. In this regard, letrozole produced fewer preovulatory follicles and did not significantly increase endometrium thickness, but significantly improved pregnancy outcomes in comparison to CC and cetrorelix acetate.

The stair-step approach in treatment of anovulatory PCOS patients

Clomiphene citrate (CC) is a widely accepted first-line treatment for anovulatory patients with polycystic ovarian syndrome (PCOS). The current practice is to prescribe CC with gradual dose increments until ovulation is achieved. Typically, progesterone withdrawal bleeding is induced between each dose increment and before the commencement of gonadotropin therapy in CC-resistant patients. It has been recently suggested that dose increments of CC can be administered once failure to induce ovulation at a certain dose has been documented, without induction of progesterone withdrawal bleeding, and this approach has been nicknamed the clomiphene-citrate stair-step (CC-SS) protocol. The same principle has been found feasible before introducing gonadotropin therapy in CC-resistant PCOS patients. Our objective was to review the world literature on the CC-SS protocol and to summarize our own experience with extending the CC-SS approach to initiation of gonadotropin therapy. Studies on CC-SS protocol (n = 4) have found that this approach leads to a significant reduction of the time to ovulation and to an increased ovulation rate. In our own retrospective case series, 18 CC-resistant PCOS patients initiated gonadotropin stimulation without induction of progesterone withdrawal bleeding, using the chronic low-dose regimen. The time to ovulation in the study group was 54.2 ± 6.2 days, while the estimated time to ovulation calculated according to the traditional approach was approximately 110 days. The clinical pregnancy rate was 44% (8/18), and all pregnancies were singletons. One patient miscarried; hence, the live birth rate was 38.9% (7/18). In summary, the CC-SS approach and its extension to the initiation of gonadotropin therapy results in considerable reduction of the time to ovulation, and favorable ovulation rates and reproductive outcome. Large-scale confirmation of these findings by properly designed randomized controlled trials may lead to a change of practice in the treatment of anovulatory infertility in PCOS patients, allowing simplification of treatment and a shorter time to ovulation and pregnancy.

Ovulation rates in a stair-step protocol with Letrozole vs clomiphene citrate in patients with polycystic ovarian syndrome

Purpose

To compare ovulation rates between Letrozole and Clomiphene Citrate (CC) using a stair-step protocol to achieve ovulation induction in women with Polycystic Ovarian Syndrome (PCOS).

Methods

This is a retrospective cohort of predominantly Hispanic PCOS women of reproductive age who completed ovulation induction (OI) comparing women who underwent Letrozole stair-step protocol to those who underwent OI with CC stair-step. All women had a diagnosis of PCOS based on the 2003 Rotterdam criteria. For both protocols, sequentially higher doses of Letrozole or CC were given 7 days after the last dose if no dominant follicles were seen on ultrasonography. The primary outcome was ovulation rate (determined by presence of a dominant follicle) between the two treatment groups. Secondary outcomes included time to ovulation, clinical pregnancy rates and side effects.

Results

49 PCOS patients completed a Letrozole stair-step cycle and 43 completed a CC stair-step cycle for OI. Overall, demographics were comparable between both groups. Ovulation rates with the Letrozole stair-step protocol were equivalent to CC stair-step protocol (96% vs 88%, p = 0.17). Although the mean time (days) to ovulation was shorter in the Letrozole group (19.5 vs 23.1, p = 0.027), the pregnancy rates were similar for both groups.

Conclusions

This is the first study to date that has compared the efficacy of the stair-step protocol in PCOS patients using Letrozole and CC. Both Letrozole and CC can be prescribed in a stair-step fashion. Letrozole stair-step was as efficacious as CC stair-step; patients achieved comparable rates of ovulation and clinical pregnancy. Time to ovulation was shorter in the Letrozole protocol.

Usefulness of intermittent clomiphene citrate treatment for women with polycystic ovarian syndrome that is resistant to standard clomiphene citrate treatment

PURPOSE

Clomiphene citrate (CC) has been used as a first-line treatment for anovulatory polycystic ovary syndrome (PCOS). However, some patients with PCOS are resistant to standard CC treatment. In this study, a new CC treatment protocol was developed, named "intermittent CC treatment" (ICT) and its efficacy was investigated on the induction of follicular growth in patients with PCOS who were resistant to standard CC treatment.

METHODS

Of the 42 patients with PCOS who were resistant to standard CC treatment (50 mg/day, 5 days), 26 underwent ICT. They were given 100 mg/day of CC for 5 days from the next menstrual cycle day (MCD) 5 (first CC). If follicular growth was not observed on MCD 14, they were given 100 mg/day of CC for 5 days (MCD 14-MCD 18) (second CC). If follicular growth still was not observed on MCD 23, they were treated with CC again in the same way (third CC).

RESULTS

The first CC, second CC, and third CC were effective for 3/26 (11.5%) patients, 12/23 (52.2%) patients, and 6/11 (54.5%) patients, respectively. In total, ICT was effective for 21/26 (80.8%) patients with CC-resistant PCOS.

CONCLUSION

Thus, ICT is a useful treatment and could be an alternative to gonadotropin therapy for patients with CC-resistant PCOS.

Ovulation Induction Using Clomiphene Citrate Using Stair - Step Regimen versus Traditional Regimen in Polycystic Ovary Syndrome Women - A Randomized Control Trial

Objective:

To determine the efficacy of the stair-step protocol (SSP) using clomiphene citrate (CC) in patients with polycystic ovary syndrome (PCOS) and compare it with traditional regimen.

Design:

This was randomized control trial.

Setting:

Infertility Clinic.

Patient(s):

Sixty infertile PCOS women.

Intervention(s):

Patients were randomized into the study (SSP – 30 patients) and control group (traditional protocol – 30 patients). In the SSP, patients were treated with CC 50 mg/day for 5 days and in nonresponsive patients, the dosage was increased to 100 mg/day for 5 days in the same cycle. Maximum dose of 150 mg was given until the dominant follicle was generated. In control group, the dose increment in nonovulatory cases was done in subsequent cycle. Ultrasonography follow-up was done to detect ovulation.

Main Outcome Measure(s):

Ovulation rate and duration of treatment.

Results:

Ovulation (66.7% vs. 50% respectively) and pregnancy rates (26.7% vs. 15.7%) were similar between the stair step and the control group. The duration of treatment was significantly shorter in stair step compared to traditional protocol (17.23 vs. 53 days). CC 100 mg was the most effective dose for ovulation in either group. There were no significant differences in the systemic side effect.

Conclusions:

By using SSP, effective treatment is provided in significantly shorter time period without any detrimental effect on the ovulation and pregnancy rates.

Clomiphene Stair-Step Protocol for Women With Polycystic Ovary Syndrome

OBJECTIVE

To compare time to ovulation, ovulation rates, and side effect profile of traditional and the stair-step protocol for ovulation induction using clomiphene citrate in women with polycystic ovary syndrome (PCOS).

METHODS

We performed a retrospective study of women seeking care for infertility with a diagnosis of PCOS at a university-based infertility clinic from July 2012 to July 2014. We included patients who were resistant to the initial starting dose of 50 mg clomiphene. The primary outcome was time to ovulation. Secondary outcomes included ovulation rates, clinical pregnancy rates, and mild and moderate-to-severe side effects based on dose. For the traditional protocol, higher doses of clomiphene were used each subsequent month if no ovulation occurred. For the stair-step protocol, higher doses of clomiphene were given 7 days after the last dose if no dominant follicles were seen on ultrasonography. Our study had 80% power to detect a 20% difference in ovulation.

RESULTS

One hundred nine patients were included in the analysis with 66 (60.6%) in the traditional and 43 (39.4%) in the stair-step protocol. Age and body mass index were similar between groups. The time to ovulation was decreased in the stair-step protocol group compared with the traditional protocol group (23.1±0.9 days vs 47.5±6.3 days). Ovulation rates were increased in the stair-step group compared with the traditional group at 150 mg (16 [37%] vs 8 [12%], P=.004) and at 200 mg (9 [21%] vs 3 [5%], P=.01). Pregnancy rates were similar between groups once ovulation was achieved (12 [18.1%] vs 7 [16.3%], P=.08). The stair-step protocol had an increased incidence of mild side effects (vasomotor flushes, headaches, gastrointestinal disturbance, mastalgia, changes in mood; 18 [41%] vs 8 [12%]), but there was no difference in the incidence of severe side effects (headaches, visual disturbances).

CONCLUSION

For women with PCOS, the stair-step clomiphene protocol is associated with decreased time to ovulation and increased ovulation rates at higher doses when compared with the traditional protocol.

Extension of the clomiphene citrate stair-step protocol to gonadotropin treatment in women with clomiphene resistant polycystic ovarian syndrome

Our objective was to evaluate the safety and efficacy of direct initiation of gonadotropin ovarian stimulation without prior withdrawal bleeding in anovulatory clomiphene citrate (CC) resistant polycystic ovarian syndrome (PCOS) patients. Eighteen PCOS patients underwent ovulation induction with CC using a stair-step regimen. Patients who failed to respond to the maximal dose of CC initiated gonadotropin stimulation without inducing withdrawal bleeding, using the chronic low dose regimen. The primary outcome measure was the time to ovulation from the beginning of CC treatment until the day of ovulatory trigger. This was compared with the time to ovulation calculated according to the traditional approach, which includes inducing progesterone withdrawal bleeding between each CC dose increment and before gonadotropin therapy. The time to ovulation in the study group was 67.0 ± 6.8 days. The estimated time to ovulation according to the traditional approach was approximately 110 days. The clinical pregnancy rate was 44% (8/18), and all pregnancies were singletons. One patient miscarried; hence the live birth rate was 38.9% (7/18). Direct initiation of gonadotropin therapy without prior induction of withdrawal bleeding in clomiphene resistant PCOS patients results in considerable reduction of the time to ovulation and is both safe and efficacious.

Randomized Trial Comparing the Effect of Endometrial Shedding With Medroxyprogesterone Acetate With Random Start of Clomiphene Citrate for Ovulation Induction in Oligo-ovulatory and Anovulatory Women

OBJECTIVE

A recent retrospective study demonstrated that anovulatory infertile women who did not have a progestogen-induced withdrawal bleed before treatment with clomiphene citrate (CC) had higher pregnancy rates than women who had a withdrawal bleed and those who had spontaneous menstrual bleeding. We sought to assess endometrial thickness at the time of ovulation in oligo-ovulatory and anovulatory women who took CC with or without a preceding progestogen-induced withdrawal bleed.

METHODS

We conducted a pilot randomized trial in which women with infertility and oligomenorrhea or amenorrhea were randomly assigned to take either CC after a withdrawal bleed induced by medroxyprogesterone acetate (MPA) 10 mg daily for 10 days or to take CC without such a bleed. Study participants underwent cycle monitoring with ultrasound assessment of endometrial thickness at the time of LH surge or a human chorionic gonadotropin trigger, followed by timed intercourse or intrauterine insemination. Women who had not ovulated by cycle day 21 took an increased dose of CC, with or without an MPA-induced withdrawal bleed, to a maximum of three cycles. Participants and nurses were asked to complete a questionnaire about the study.

RESULTS

There was no significant difference in endometrial thickness on the day of LH surge or human chorionic gonadotropin trigger between women who had a progestogen-induced withdrawal bleed and those who did not (P = 0.65). On average, the time to ovulation was 15 days longer in women who took MPA than in women who did not, but this difference was not statistically significant (P = 0.65). Satisfaction with the study was reported as high by both patients and nurses.

CONCLUSION

In anovulatory or oligo-ovulatory women treated with CC, we found no significant difference in endometrial thickness whether or not the use of CC was preceded by a withdrawal bleed induced by MPA.

Polycystic ovary syndrome: chemical pharmacotherapy

INTRODUCTION

Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disease among women of childbearing age. The clinical features are heterogeneous and vary in intensity. Hirsutism, menstrual disorders and infertility are the most frequent conditions observed; however, long-term complications (dyslipidemia, hypertension, cardiovascular disease, type 2 diabetes mellitus, endometrial cancer) are also often described. Each disorder may be managed by tailored strategies, employing sequential or combined pharmacological and/or non-pharmacological treatment.

AREAS COVERED

The authors review the drugs used for PCOS management and discuss new approaches. A systematic MEDLINE search regarding the randomized controlled trials, retrospective and observational studies about medical treatments of PCOS, the Cochrane library for reviews and also search for registered trials on ClinicalTrials.gov is performed.

EXPERT OPINION

A uniform treatment for PCOS patients does not exist. Clinicians should perform an accurate evaluation of patients' characteristics, identifying the phenotypic target and, subsequently, the best-tailored treatment to manage one or more clinical issues. Lifestyle intervention should always be the first recommended approach unless other issues indicate that drug or hormonal interventions are superior.

Endocrine and reproductive effects of polycystic ovarian syndrome

Management strategies for overweight and obese women with polycystic ovarian syndrome (PCOS) who desire fertility should include weight loss. Even a small reduction in body weight can improve ovulatory function and pregnancy rate and reduce adverse obstetric outcomes. New data suggest that letrozole should be considered as the new first-line medical treatment of anovulatory infertility in PCOS over clomiphene citrate. Second-line treatments for anovulatory infertility include in vitro fertilization, gonadotropins, or ovarian drilling.

Optimal management of subfertility in polycystic ovary syndrome

The purpose of this paper is to provide a stepwise approach to treating the infertility/subfertility associated with polycystic ovary syndrome. Defining polycystic ovary syndrome in a patient requires first investigating other possible causes for polycystic ovary morphology, acne, hirsutism, obesity, and the metabolic derangements that often accompany polycystic ovary syndrome. Beginning with lifestyle modification and use of metformin, the progressive inclusion of more intensive therapies for induction of ovulation is described. Second-line treatments are discussed and the new findings from a large multicenter trial are discussed in the context of evidence-based treatment strategies for first-line agents. Finally, monofollicular development as a treatment goal and in vitro fertilization are discussed for those with recalcitrant disease.

Use of clomiphene citrate in infertile women: a committee opinion

This committee opinion describes the use of clomiphene citrate, including indications, use, monitoring, and side effects. There is also a discussion of adjuvants and alternatives to clomiphene citrate therapy.

Endometrial shedding effect on conception and live birth in women with polycystic ovary syndrome

OBJECTIVE

To estimate whether progestin-induced endometrial shedding, before ovulation induction with clomiphene citrate, metformin, or a combination of both, affects ovulation, conception, and live birth rates in women with polycystic ovary syndrome (PCOS).

METHODS

A secondary analysis of the data from 626 women with PCOS from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Cooperative Reproductive Medicine Network trial was performed. Women had been randomized to up to six cycles of clomiphene citrate alone, metformin alone, or clomiphene citrate plus metformin. Women were assessed for occurrence of ovulation, conception, and live birth in relation to prior bleeding episodes (after either ovulation or exogenous progestin-induced withdrawal bleed).

RESULTS

Although ovulation rates were higher in cycles preceded by spontaneous endometrial shedding than after anovulatory cycles (with or without prior progestin withdrawal), both conception and live birth rates were significantly higher after anovulatory cycles without progestin-induced withdrawal bleeding (live births per cycle: spontaneous menses 2.2%; anovulatory with progestin withdrawal 1.6%; anovulatory without progestin withdrawal 5.3%; P<.001). The difference was more marked when rate was calculated per ovulation (live births per ovulation: spontaneous menses 3.0%; anovulatory with progestin withdrawal 5.4%; anovulatory without progestin withdrawal 19.7%; P<.001).

CONCLUSION

Conception and live birth rates are lower in women with PCOS after a spontaneous menses or progestin-induced withdrawal bleeding as compared with anovulatory cycles without progestin withdrawal. The common clinical practice of inducing endometrial shedding with progestin before ovarian stimulation may have an adverse effect on rates of conception and live birth in anovulatory women with PCOS.

LEVEL OF EVIDENCE

II.

Administration of clomiphene citrate in patients with polycystic ovary syndrome, without inducing withdrawal bleeding, achieves comparable treatment characteristics and outcome

In an attempt to evaluate the effect of random timing of the start of clomiphene citrate (CC) treatment in anovulatory patients with polycystic ovary syndrome on treatment characteristics and outcome, with no regard to time of menstruation, we studied 291 women in their first CC treatment cycle. Duration of treatment was shorter by 2 days and number of leading follicles was higher when treatment was started late (7-29 days from starting a bleed, as compared with day 5), but no effect of starting day was observed on response rate to CC, maximal E(2) level, endometrial thickness, and pregnancy rate.