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*CLOMIPHENE
*METFORMIN HYDROCHLORIDE
The Journal of Clinical Endocrinology & Metabolism Vol. 89, No. 10 4801-4809
Copyright © 2004 by The Endocrine Society


Special Feature

Metformin Administration Versus Laparoscopic Ovarian Diathermy in Clomiphene Citrate-Resistant Women with Polycystic Ovary Syndrome: A Prospective Parallel Randomized Double-Blind Placebo-Controlled Trial

Stefano Palomba, Francesco Orio, Jr., Luciano Giovanni Nardo, Angela Falbo, Tiziana Russo, Domenico Corea, Patrizia Doldo, Gaetano Lombardi, Achille Tolino, Annamaria Colao and Fulvio Zullo

Departments of Obstetrics and Gynecology (S.P., A.F., T.R., D.C., F.Z.) and Experimental Medicine (P.D.), University "Magna Graecia" of Catanzaro, 88100 Catanzaro, Italy; Departments of Molecular and Clinical Endocrinology and Oncology (F.O., G.L., A.C.), and Obstetrics and Gynecology (A.T.), University "Federico II" of Naples, 80131 Naples, Italy; and Imperial College (L.G.N.), St. Mary’s Hospital, London W2 1NY, United Kingdom

Address all correspondence and requests for reprints to: Stefano Palomba, M.D., Department of Gynecology and Obstetrics, University "Magna Graecia" of Catanzaro, Via Nicolardi 188, 80131 Naples, Italy. E-mail: stefanopalomba{at}tin.it.


    Abstract
 Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
At present, it is unclear what the role is of laparoscopic ovarian diathermy (LOD) and of metformin administration as second-line treatments for ovulation induction in women with polycystic ovary syndrome (PCOS) after failure of clomiphene citrate (CC) treatment. The aim of the present study was to compare in a randomized double-blind placebo-controlled fashion the effectiveness of LOD with metformin administration in the treatment of CC-resistant women with PCOS. A total of 120 overweight primary infertile anovulatory CC-resistant women with PCOS were enrolled and randomized into two groups of treatment. Group A underwent diagnostic laparoscopy, whereas group B underwent LOD. At hospital discharge, the patients were treated for 6 months with metformin cloridrate (group A; 850 mg twice daily) or with multivitamins (group B). The ovulation, pregnancy, abortion, and live-birth rates were evaluated. At the end of the study, the total ovulation rate was not statistically different between both treatment groups (54.8 vs. 55.1% in groups A and B, respectively), whereas the pregnancy (18.6 vs. 13.4%), the abortion (15.4 vs. 29.0%), and the live-birth (82.1 vs. 64.5%) rates were significantly (P < 0.05) different between the two groups. Our data show that metformin administration is more effective than LOD in overall reproductive outcomes in overweight infertile CC-resistant women with PCOS.


    Introduction
 Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
POLYCYSTIC OVARY SYNDROME (PCOS) is the most common reproductive endocrinopathy, which affects 5–10% of women in the reproductive age and is a major cause of infertility (1, 2, 3, 4). Notwithstanding the different criteria proposed for the diagnosis of PCOS (5, 6), the crucial alteration remains, probably, ovarian dysfunction caused by chronic anovulation, which makes this syndrome an important social problem for its implications in the field of sterility.

Several approaches have been proposed to induce ovulation in women with PCOS (7). At the present, clomiphene citrate (CC) administration is considered the first choice treatment in PCOS women (7, 8), whereas no clear data are in the literature regarding the management of CC-resistant women with PCOS.

During the last years we have assisted in the development of laparoscopic techniques as minimally invasive surgery. At present, laparoscopy is widely diffused throughout the world, and it has generated new interest in surgical ovulation induction (7, 9, 10). Contrary to laparotomic wedge resection, laparoscopic ovarian diathermy (LOD) seemed to induce a low rate of peritoneal adhesions (11, 12, 13, 14, 15). LOD is effective in terms of reproductive outcomes, with ovulation and pregnancy rates of 70 and 55%, respectively (7, 9, 10). Consequently, the surgical management of PCOS has become widely accepted and used.

Recently, a lot of attention has been placed also on drugs with insulin-sensitizing action in PCOS patients to induce simple ovulation in CC-resistant or nonresistant patients (7, 16, 17, 18). In a systematic review (18), the effectiveness of insulin-sensitizing drugs in improving clinical and biochemical features of PCOS has been studied, confirming that metformin is effective in achieving ovulation in women with PCOS in comparison with placebo and in improving the ovulation rate also as additional treatment in women who received CC.

Contrary to gonadotropins administration, both therapeutic alternatives, i.e. LOD and metformin administration, are characterized by few side effects, by the simplicity of management because there is no need for ongoing monitoring, and by a positive impact at the endocrine and metabolic level (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18).

At the moment, only one study has compared metformin with LOD as a treatment to induce spontaneous ovulation or pregnancy in CC-resistant women with PCOS (19). The aim of the present study was to compare in a randomized, double-blind, placebo-controlled fashion the effectiveness of LOD compared with metformin administration in the treatment of CC-resistant women with PCOS.


    Subjects and Methods
 Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
The procedures used were in accordance with the guidelines of the Helsinki Declaration on human experimentation. The study was approved by the Institutional Review Board of the University "Magna Graecia" of Catanzaro. The purpose of the protocol was carefully explained to each woman, and a written consent was obtained from each subject before beginning the study.

Subjects

Between October 2001 and December 2002, a total of 120 overweight primary infertile anovulatory CC-resistant women with PCOS were enrolled. The diagnosis of PCOS was initially made according to the National Institutes of Health criteria (5). CC resistance was defined as failure to ovulate during a total of at least three consecutive cycles using doses of CC of 150 mg for 5 d from d 3–7 of withdrawal bleeding induced with medroxyprogesterone acetate. A body mass index (BMI) between 25 and 30 was considered as overweight (20).

Exclusion criteria for all subjects included age of less than 22 yr or more than 34 yr, hypothyroidism, hyperprolactinemia, Cushing’s syndrome, nonclassical congenital adrenal hyperplasia, and current or previous (within the last 6 months) use of oral contraceptives, glucocorticoids, antiandrogens, ovulation induction agents, antidiabetic or antiobesity drugs, or other hormonal drugs. The presence of hyperprolactinemia was excluded with a single assay of plasma prolactin (PRL) levels [normal values < 25 ng/ml (SI, <15 µg/liter)]. In women with serum PRL levels greater than 25 ng/ml (SI, >15 µg/liter), hyperprolactinemia was excluded considering the average value of serum PRL assayed at 0800 h for three times every 15 min. Nonclassical congenital adrenal hyperplasia was excluded with a single measure of serum 17-hydroxyprogesterone (17-OHP) levels [normal value < 1.98 µg/liter (SI, 6.0 nmol/liter)].

No subject was affected by any neoplastic, metabolic, hepatic, or cardiovascular disorder or other concurrent medical illness (i.e. diabetes, renal disease, or malabsorptive disorders). Specifically, PCOS women with glucose intolerance, as assessed by World Health Organization criteria (21), were excluded from the study. We excluded also women who were intending to start a diet or a specific program of physical activity. Other exclusion criteria were organic pelvic diseases, previous pelvic surgery, suspected peritoneal factor infertility, and tubal or male factor infertility. Tubal infertility and male factor infertility were excluded with a hysterosalpingogram and with semen analysis, respectively.

All subjects were nonsmokers and had normal physical activity, and none drank alcoholic beverages.

Protocol and treatment

At study entry, all subjects had venous blood drawn to evaluate the complete hormonal assays, serum glucose and insulin levels.

At baseline, in both groups we calculated the Ferriman-Gallwey score (22) and evaluated patients’ daily physical activity, job, and daily activities using a semiquantitative questionnaire (23).

During the same visit, all subjects underwent transvaginal ultrasonography (TV-USG) and anthropometric measurements. The anthropometric measurements included height, weight, BMI, and waist-to-hip ratio (WHR). Body height and weight were measured without shoes and clothes, respectively. BMI was measured as the ratio between the weight and the square of the height (kg/m2). WHR was calculated as the ratio between the smallest circumference of torso (between the 12th rib and the iliac crest) and the circumference of the hip (considered as the maximal extension of the buttocks). WHR was calculated with the patients in standing position with relaxed abdomen, arms at sides, and joined feet. The same operator, who was blinded to the treatment allocation, performed all measurements.

The subjects were randomly allocated into two treatment groups of 60 women each (groups A and B). The randomization was carried out using online software (www.randomization.it) to generate a random allocation sequence in double block as method of restriction. The random allocation sequence was concealed until the interventions were assigned.

All subjects underwent laparoscopy. Specifically, diagnostic laparoscopies were performed in group A. For the duration of the study, each patient was blinded with regard to the surgical treatment performed.

At hospital discharge, group A was treated with metformin cloridrate (Metforal, Laboratori Guidotti, Pisa, Italy) at a dosage of 850 mg twice daily, whereas group B received multivitamins (two tablets/day orally). The patients were instructed to take the tablets with the meals. The drug and the placebo were packaged in the University of Catanzaro pharmacy and labeled according to subject number. The duration of treatment was 6 months. For the entire period of study, operators and patients were blinded to the treatment allocation.

After 6 months of metformin or placebo treatment, in women who did not achieve ovulation, CC (Serophene, Serono, Rome, Italy) was administered at doses of 150 mg daily for five times from d 3–7 of progesterone (P)-induced uterine bleeding. Patients who conceived suspended the treatment (metformin or placebo tablets for groups A and B, respectively) (24, 25, 26).

At the end of the study, a 6-month extension of the follow-up period was done to obtain the live-birth rate for each treatment group.

Each woman was asked to have intercourse every 2 d for four times from the sonographic detection of a follicle with a mean diameter of at least 18 mm (detailed below).

Throughout the study, no changes in diet and in physical activity were implemented. On the contrary, the subjects were instructed to follow their usual diet and physical activity.

Standard clinical evaluations and laboratory analyses, including hematological, renal function, and liver function tests and microscopic examinations of sediment from midstream urine specimens, were performed at study entry and after 6 months of treatment.

The subjects were instructed to report in a daily diary the onset of any adverse experiences (AEs), specifying the severity, duration, and a possible cause-effect relationship with drug administration. To evaluate compliance with the treatment and with the protocol, the number of tablets forgotten, the changes in diet, physical activity, and weight, as well as the timing of intercourse were also recorded in the same diary.

Surgical procedures

The same experienced operator performed the laparoscopic procedures. After induction of general anesthesia, the patient was placed in the low lithotomic position to perform pelvic laparoscopy and vaginal manipulations. Immediately before surgery, an antibiotic therapy was given iv. A Foley catheter was inserted. After executing a pneumoperitoneum using a Verres needle, a 10-mm videolaparoscope was inserted umbilically, followed by the lateral insertion of two 5-mm ancillary trocars in the left and right iliac fossa. A careful inspection of the pelvic cavity was performed in each patient. Only in group B the LOD followed the diagnostic procedure. The LOD was performed as previously described by Tulandi (27). The ovary was immobilized with a laparoscopic forceps, and three to six punctures were performed with an insulated needle cautery of 36 mm (Karl Storz GmbH and Co. KG, Tuttlingen, Germany). The needle was inserted for its whole length as perpendicularly as possible to the ovarian surface after setting the electrosurgical device (Erbotom ACC 450, Erbe GmbH, Tubingen, Germany) at a cutting current of 100 W power. The monopolar coagulating current was then set at 40 W power, and the needle was activated for 2–3 sec at each point. The number of punctures made in each ovary depended on its size. At completion of the procedure, the ovarian surface was washed with a crystalloid solution. The injured areas were completely covered with hyaluronic acid gel (Hyalobarrier gel, Baxter, Pisa, Italy) (28).

Duration of surgical procedure, blood loss, and hospital stay were recorded. All intra- and postoperative complications were carefully recorded for each group. Based on clinical conditions, patients were discharged either the same day of the surgical procedure or 1 d postoperatively.

Biochemical assays

All blood samples were obtained in the morning between 0800 and 0900 h after an overnight fast (at least 12 h) and a 30-min resting in the supine position during the early proliferative phase (d 2–3) of the spontaneous or P-induced withdrawal uterine bleeding. Blood samples (5 ml) were collected into tubes containing EDTA and were immediately centrifuged at 4 C for 20 min at 1600 x g, and plasma samples were stored at –20 C.

Plasma LH, FSH, PRL, estradiol, P, 17-OHP, testosterone (T), androstenedione, and dehydroepiandrosterone sulfate were measured by specific RIA as previously reported (29). SHBG levels were measured also using an immunoradiometric assay (29). Serum insulin was measured by a solid-phase chemiluminescent enzyme immunoassay using commercially available kits. Blood glucose levels were determined by the glucose oxidase method (29).

In each woman, the free androgen index (FAI) was calculated using the following formula: T (nmol/liter)/SHBG x 100 (30). Glucose and insulin values were detected also after an oral glucose tolerance test (OGTT). Glucose and insulin concentrations were measured also 30 min after insertion of the iv catheter to detect the fasting levels (time 0) before OGTT. Subsequently, each subject received orally a 75-g glucose load. Additional blood samples (10 ml each) were obtained at 30-min intervals for the next 3 h during the infusion period (times 30, 60, 90, and 120 min), and glucose and insulin concentrations were determined. Glucose tolerance was assessed by World Health Organization criteria (21). In both groups, the glucose and insulin response to OGTT was analyzed by calculating the area under the curve (AUC). The AUC for glucose (AUCglucose) and insulin (AUCinsulin) were determined according to the mathematical method described by Tai (31) for the metabolic curves. The AUCglucose/AUCinsulin ratio was also calculated in each subject (29).

Clinical outcomes

The subjects were instructed to report in a daily diary the characteristics of their menstrual cycles. Specifically, the length and the frequency of the menstrual bleedings were evaluated. The frequency of menstrual cycles was evaluated as the percentage of observed menses relative to the number of expected menses.

The quantity of the cyclical uterine bleedings was also evaluated subjectively by each woman using a rank analog scale ranging from 1–10. A value of 0 was given arbitrarily in the absence of menses, a value of 5 was given for uterine bleedings defined as normal, and a value of 10 for uterine bleeding defined as severe.

Reproductive outcomes

During the 6 months of treatment, the ovulation, pregnancy, abortion, and live-birth rates were evaluated in each woman.

The ovulatory cycles were evaluated using TV-USG measurements. The scans were performed by the same experienced operator every 3 d, starting on d 7 after intervention (during the first month from surgery), and subsequently on d 2 after the onset of menses using an ultrasonic scanner (Aplio, Toshiba Medical Systems, Rome, Italy) equipped with a 7.5-MHz vaginal probe. When the follicular dimensions achieved at least 16 mm, the TV-USG was performed daily. Follicular development was studied by measuring the two main diameters of the follicle. The day of ovulation was retrospectively defined with the observation of decreased follicular dimensions and of liquid in the cul-de-sac and confirmed by a plasma P assay >10 ng/ml (>31.8 nmol/liter; SI units).

Ovulation rate was calculated as the percentage of ovulatory cycles relative to total cycles. Pregnancy rate was defined as the percentage of pregnancies relative to total cycles. A rising ß-human chorionic gonadotropin level and the sonographic evidence of intrauterine gestational sac were considered criteria to define a pregnancy. Abortion rate was defined as the percentage of miscarriages during the first 12 wk of gestation relative to total pregnancies. Live-birth rate was defined as the percentage of women with baby alive relative to women who achieved a pregnancy.

Cost of the treatments

A comparison in terms of costs was performed between LOD and metformin treatment.

To assess the cost of LOD, we considered the day-surgery fee, the surgeon’s fee, the anesthetist’s fee, and assistant’s fee as absolute costs in euros. All equipment and the disposables used to perform diagnostic or operative laparoscopies were resterilized and provided by the Laparoscopic Center of the University of Catanzaro. Thus, no additional cost was calculated for the surgical equipment.

The cost of medical therapy was determined considering the average cost of six cycles of metformin cloridrate administration at doses of 1700 mg daily.

Statistical analysis

The primary endpoint of our study was the ovulation rate. Based on the assumption that the expectant ovulation rate is 70% in the control group (LOD only) (12) and that a difference in ovulation rate is clinically relevant only for differences higher than 20%, we needed to enroll 60 patients for each group to demonstrate a difference of 20% between control and experimental groups (metformin group) and to define statistical significance between the groups with {alpha} = 0.05 and ß = 0.20.

The demographic and biochemical data were analyzed by the Student’s t test for unpaired data. The Mann-Whitney U test for independent groups of data was used to compare hospital stay, physical activity, duration of operation, and intraoperative blood loss. The Fisher exact test was used to compare the incidences of complications and of AEs between treatment groups. The differences in length of the menses at different times of treatment were calculated using ANOVA for repeated measures with Bonferroni’s test for multiple comparisons. Wilcoxon’s rank-sum test was used to compare the quantity of the menses between and within groups. The frequency (percentage) of menstrual cycles was also analyzed with the use of the {chi}2 test. Ovulation, pregnancy, abortion, and live-birth rates were also evaluated using the {chi}2 test. The costs of the two treatments were also compared with the use of the Student’s t test for unpaired data.

Data were analyzed using the intention-to-treat method and expressed as mean ± SD. A P value < 0.05 was considered statistically significant. The Statistics Package for Social Science (SPSS 11.0, SPSS Inc., Chicago, IL) was used for statistical analyses.


    Results
 Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
An overview of the trial is shown in Fig. 1Go.



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FIG. 1. An overview of the trial.

 
Demographic and hormonal data

Patients’ characteristics are presented in Table 1Go. After randomization, the two groups were similar for age and BMI. No difference in WHR, duration of infertility, Ferriman-Gallwey score, physical activity score, or any biochemical assay was observed between the two groups (Table 1Go). Also, no difference between groups was detected in FAI and in glucose and insulin levels (Table 1Go).


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TABLE 1. Clinical, hormonal, and metabolic data of PCOS women treated with diagnostic laparoscopy plus metformin (group A) or LOD plus placebo (group B) at study entry

 
At study entry, all women had polycystic ovaries at TV-USG examination.

Dropouts

The numbers of withdrawals were similar in the two groups (six and five women in groups A and B, respectively). Specifically, six patients (four and two in groups A and B, respectively) were excluded after laparoscopy for the presence of minimal endometriosis. One woman from each group was excluded by final analysis for lack of compliance with the treatment (they did not take tablets during the first 3 wk for drug-related AEs). Finally, one woman from group A and two women from group B were excluded because a reduction in body weight (>5% from basal value) was observed after the first 3 months of the study.

Results included in this study were obtained from a total of 109 patients (mean age, 27.2 ± 2.4 yr; range, 24–30 yr), 54 and 55 women in groups A and B, respectively.

Surgical results

Before surgery, the red blood cell count, hematocrit, serum hemoglobin, and iron levels were not statistically different between the two groups. The same parameters were also similar in both groups after surgical intervention (data not shown). In particular, the difference between serum hemoglobin levels measured before and after surgery was similar in both groups (0.49 ± 0.17 vs. 0.35 ± 0.16 for groups A and B, respectively).

Laparoscopies were completed successfully in all women, and no case was converted to laparotomy. No difference in surgical complications was detected between the two groups. No significant differences were observed between groups in operative time (min ± SD, 16.6 ± 3.2 vs. 19.2 ± 4.3 for groups A and B, respectively) or in postoperative hospital stay (days ± SD, 0.52 ± 0.24 vs. 0.51 ± 0.23 for groups A and B, respectively). No intraoperative or postoperative complications were detected in either group.

In two cases for each treatment group, we observed a minimal endometriosis (32) that was treated with a conservative approach consisting of electrocautery ablation or excision of visible pelvic endometriotic lesions. A histological analysis of the lesions was also performed to confirm the diagnosis.

Clinical outcomes

No difference in the length (Fig. 2Go) or in the quantity (data not shown) of menstrual bleedings was observed throughout the study.



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FIG. 2. Mean length of the menstrual bleedings in both treatment groups throughout the study.

 
The frequency of the menstrual cycles was similar between the two treatment groups (Fig. 3Go).



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FIG. 3. Mean frequency of the menstrual cycles in both treatment groups throughout the study.

 
Reproductive outcomes

In Table 2Go are detailed the ovulation and pregnancy rates for each month of observation in both treatment groups. Table 3Go summarizes the reproductive outcomes observed during the study in both treatment groups.


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TABLE 2. Ovulation and pregnancy rates in PCOS women treated with diagnostic laparoscopy plus metformin (group A) or LOD plus placebo (group B) for each month of follow-up

 

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TABLE 3. Reproductive outcomes in PCOS women treated with diagnostic laparoscopy plus metformin (group A) or LOD plus placebo (group B)

 
The subjects of groups A and B were studied for a total of 210 and 231 cycles, respectively. At the end of the study, the total ovulation rate was not statistically different between both treatment groups (54.8 vs. 55.1% in groups A and B, respectively). The pregnancy rate was significantly (P < 0.05) higher in group A in comparison with group B (18.6 vs. 13.4% in groups A and B, respectively). The abortion rate was significantly (P < 0.05) lower in group A in comparison with group B (15.4 vs. 29.0% for groups A and B, respectively). The live-birth rate was significantly (P < 0.05) higher in group A than in group B (82.1 vs. 64.5% in groups A and B, respectively). None of the women had multiple pregnancies.

After six cycles of treatment, the cumulative pregnancy rate was 72.2% (39 of 54) and 56.4% (31 of 55) for groups A and B, respectively.

At the end of the six-cycle treatment, 3 of 15 and 4 of 24 PCOS women in groups A and B, respectively, had regular ovulatory menstrual cycles. The other women were still oligo- or amenorrheic.

Side effects

Throughout the study, the two treatment schedules were generally well tolerated, and the total incidence of all AEs was not significantly different between the two groups.

The incidence of drug-related AEs due to metformin was, furthermore, significantly (P < 0.05) higher in comparison with placebo. Specifically, during the first months of treatment, 12 of 54 women (22.2%) treated with metformin reported diarrhea, flatulence, and nausea, whereas three of 55 women (5.5%) treated with placebo reported gastralgia and constipation. No serious AEs were reported during the study.

Economic data

In Table 4Go are shown the costs of an episode of LOD performed in a day-surgery center with the costs of 6 months of treatment with metformin. The LOD was significantly (P < 0.05) more expensive in comparison with 6 months of metformin administration (1050 vs. 50 euros).


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TABLE 4. Comparison between costs of LOD and 6 months of metformin administration

 

    Discussion
 Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
PCOS is associated with approximately 75% of women who suffer from infertility caused by anovulation (2, 3, 4). It is generally accepted that the first line of treatment to induce ovulation in PCOS women is CC administration (7, 8). Despite treatment with CC, a variable percentage of PCOS women remains anovulatory or does not achieve a pregnancy. In fact, the ovulation rate after CC treatment is approximately 70–80% with a pregnancy rate of approximately 40 % (7, 8).

Only a few years ago, the second-line treatments in CC-resistant PCOS women consisted of LOD or gonadotropins use. The two approaches are similar in terms of ovulation and pregnancy rates (33, 34, 35, 36, 37). Furthermore, during gonadotropins administration, a particular experience of the operator is needed as well as careful sonographic and biochemical monitoring to avoid or to reduce the risk of ovarian hyperstimulation and multiple pregnancies, particularly in PCOS subjects. In addition, the treatment with gonadotropins requires a relevant investment of time and of money (33). On the contrary, with the advent of laparoscopic techniques and with their wide use, LOD has been proposed as a once-only procedure to induce ovulation in CC-resistant PCOS women (12).

LOD is a day-surgery procedure characterized not only by an effectiveness in ovulation induction comparable to gonadotropin use (10, 37) but also by few side effects and no need for ongoing monitoring (7, 8, 9, 10). In addition, LOD has beneficial effects also at the metabolic level with an effectiveness that seems to be maintained after a long-term follow-up (38, 39, 40, 41, 42, 43, 44). Despite these favorable aspects, LOD is an invasive procedure that can be associated with pelvic adhesions formation (11, 12, 13, 14, 15).

At present, several studies (7, 16, 17, 18) have highlighted the possibility to use drugs with insulin-sensitizing action in PCOS patients to induce simple ovulation in CC-resistant or nonresistant patients. In particular, metformin, an oral biguanide administered in type-2 diabetes mellitus, has been shown to be effective in PCOS patients in terms of menstrual cyclicity and/or ovulation both in observational (45, 46, 47, 48, 49, 50, 51) and randomized controlled trials (52, 53, 54). Metformin increases the ovulation rate in patients later treated with CC (16) and improves the response to CC in CC-resistant PCOS patients (55, 56). Few and insufficient data are available in the literature regarding the administration of metformin in PCOS patients treated with gonadotropins (56, 57, 58, 59).

It is not completely certain whether metformin administration is effective in lean PCOS patients (60, 61) because these subjects are less insulin resistant than obese PCOS patients (62). On the contrary, it is possible that nonobese women with PCOS receive a similar benefit from metformin administration such as obese and/or overweight PCOS patients (63). In addition, metformin does not seem to improve or seems to have minor effects on the reproductive and endocrine outcomes in extremely obese patients with a BMI higher than 35 kg/m2 (64). With this view, in the present study we enrolled only overweight women to eliminate a possible confounding factor.

Another important confounding factor in several studies is weight loss as an independent factor improving menstrual cyclicity, ovulation, and fertility (65, 66, 67). Certainly, lifestyle changes are a first-line intervention in women with PCOS who are obese (or overweight). In this view, PCOS subjects who intended to start a diet or to increase their physical activity were encouraged but excluded from the present study protocol to avoid the interference of this pivotal factor. In addition, women who had diet- or physical activity- related weight changes throughout the study were also excluded from final analysis.

At present, only one study (19) has compared the efficacy of metformin with LOD alone in the treatment of CC-resistant women with PCOS. Furthermore, in this last study (19), if spontaneous ovulation or pregnancy was not achieved within only 3 months of treatment, CC was added with increments of 50 mg for both treatment groups. In addition, no laparoscopy was performed in the metformin group and no placebo tablets were administered in the LOD group. A significant improvement in the regularity of menstrual cycles and in the rates of ovulation and pregnancy was observed, with no difference between metformin administration and LOD. The authors (19) concluded that CC-resistant patients with PCOS can be treated effectively either by LOD or metformin without differences between treatments in terms of menstrual cyclicity and of ovulation and pregnancy rates.

Our results confirm (19) that either LOD or metformin administration are similarly effective in inducing regular ovulatory cycles in a high percentage of anovulatory PCOS women. Moreover, our data show a significant difference between groups in pregnancy rate. At present, controversial and few data exist on the reduction of fertility caused by postoperative pelvic adhesions followed by laparoscopy. Certainly, laparoscopy reduces significantly the adhesions rate in comparison with laparotomy, but it is still unknown how much this rate should be reduced to have an effect on reproductive outcomes and whether the filmy adhesions observed also after diagnostic laparoscopy could play a role. For these reasons, a diagnostic laparoscopy was performed in women treated with metformin to remove another confounding factor.

Our study confirms (33) that the routinely diagnostic laparoscopy should be avoided in infertile women without a clinical and diagnostic suspicion of peritoneal disease. In fact, in our selected series, in only 5% of cases (six of 120 women) was a mild endometriosis observed and treated.

As already reported by Fleming et al. (53), we observed during the first months of metformin treatment a rapid effect on the reproductive system. The ovulation and the pregnancy rates were constant throughout the 6 months of metformin administration. Based on these results, we feel that metformin administration should be used for at least 6 months and that the addition of CC could also start after this period in CC-resistant women.

It is well known that the abortion rate in PCOS women is generally higher than in healthy women (68, 69, 70) and that a high percentage of women with recurrent abortions are affected by PCOS (71, 72, 73, 74, 75). In the present study, the abortion rate was significantly lower in PCOS women treated with metformin in comparison with the LOD group. In the LOD group, the abortion rate was similar to those reported in PCOS women, whereas in the metformin group it was similar to healthy women (26, 27, 28, 74, 75). These findings, obtained with metformin administration until the diagnosis of pregnancy was made, could be caused by a beneficial effect of metformin on oocytes, embryos, and/or endometrium (26, 27, 28, 76, 77, 78, 79, 80).

No serious AEs were reported during the study in either group, and the metformin was generally well tolerated. Furthermore, the incidence of gastrointestinal side effects was significantly higher in the metformin group, but these symptoms were self-limiting and presented during the first months of treatment. Only three women suspended the treatment for the appearance of drug-related AEs. In agreement with Nestler’s suggestion (81), we feel that in clinical practice metformin administration should start with lower doses and should be progressively increased only after the first weeks.

An important issue followed by our study is the cost-benefit evaluation of the two protocols of management in the presence of a CC-resistant PCOS woman. Our data show that the cost of 6 months of metformin administration is approximately 20-fold less expensive than LOD. Recently, Kovacs et al. (82) have shown that LOD should be considered a second-line treatment in CC-resistant PCOS patients because its costs are significantly lower in comparison with gonadotropins use. Furthermore, we feel that these two previous therapeutic approaches should be not compared because they are conceptually too different.

In conclusion, our data show that either LOD or metformin administration is effective to induce ovulation in CC-resistant women with PCOS. A significant advantage in metformin administration seems to be related to a major improvement of pregnancy, abortion, and live-birth rates. In addition, metformin is less expensive than LOD and it doesn’t carry the usual risks of laparoscopy and general anesthesia. Based on these considerations, we feel that, at present, in an infertile anovulatory PCOS woman, LOD should be performed only during laparoscopy performed for suspected peritoneal factor or for other gynecological diseases. On the contrary, metformin administration, also as a single agent, can be considered the second-step approach to induce ovulation in PCOS women with CC resistance.


    Acknowledgments
 
We thank Dr. Francesco Manguso (University "Federico II" of Naples) for assistance in the statistical analysis and Mrs. Jean Ann Gilder (Scientific Communication) for editing the text.


    Footnotes
 
No financial support was provided by any pharmaceutical company for the present research.

Abbreviations: AE, Adverse experience; AUC, area under the curve; BMI, body mass index; CC, clomiphene citrate; FAI, free androgen index; LOD, laparoscopic ovarian diathermy; 17-OHP, 17-hydroxyprogesterone; OGTT, oral glucose tolerance test; P, progesterone; PCOS, polycystic ovary syndrome; PRL, prolactin; T, testosterone; TV-USG, transvaginal ultrasonography; WHR, waist-to-hip ratio.

Received April 10, 2004.

Accepted July 8, 2004.


    References
 Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 

  1. Frank S 1995 Polycystic ovary syndrome. N Engl J Med 333:853–861[Free Full Text]
  2. Knochenhauer ES, Key TJ, Kahsar-Miller M, Waggoner W, Boots LR, Azziz R 1998 Prevalence of the polycystic ovary syndrome in unselected black and white women of the southeastern United States: a prospective study. J Clin Endocrinol Metab 83:3078–3082[Abstract/Free Full Text]
  3. Adams J, Polson DW, Franks S 1986 Prevalence of polycystic ovaries in women with anovulation and idiopathic hirsutism. Br Med J 293:355–359
  4. Hull MG 1987 Epidemiology of infertility and polycystic ovarian disease: endocrinological and demographic studies. Gynaecol Endocrinol 1:235–245[Medline]
  5. Zawadzki JK, Dunaif A 1992 Diagnostic criteria for polycystic ovary syndrome: towards a rational approach. In: Dunaif A, Givens JR, Haseltine FP, Merriam GR, eds. Polycystic ovary syndrome. Boston: Blackwell; 337–384
  6. Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group 2004 Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Fertil Steril 81:19–25[Medline]
  7. Palomba S, Orio Jr F, Russo T, Falbo A, Cascella T, Colao A, Lombardi G, Zullo F, Is ovulation induction still a therapeutic problem in patients with polycystic ovary syndrome? J Endocrinol Invest, in press
  8. Hughes E, Collins J, Vandekerckhove P 2000 Clomiphene citrate for unexplained subfertility in women. Cochrane Database Syst Rev, vol 3
  9. Pirwany I, Tulandi T 2003 Laparoscopic treatment of polycystic ovaries: is it time to relinquish the procedure? Fertil Steril 80:241–251[Medline]
  10. Farquhar C, Vandekerckhove P, Lilford R 2001 Laparoscopic "drilling" by diathermy or laser for ovulation induction in anovulatory polycystic ovary syndrome. Cochrane Database Syst Rev 4:CD001122
  11. Gurgan T, Urman B 1994 Adhesions after ovarian drilling and intercede. Fertil Steril 62:424–426[Medline]
  12. Felemban A, Tan SL, Tulandi T 2000 Laparoscopic treatment of polycystic ovaries with insulated needle cautery: a reappraisal. Fertil Steril 73:266–269[CrossRef][Medline]
  13. Operative Laparoscopy Study Group 1991 Postoperative adhesion development after operative laparoscopy: evaluation at early second-look procedures. Fertil Steril 55:700–704[Medline]
  14. Gurgan T, Kisnisci H, Yarali H, Develioglu O, Zeyneloglu H, Aksu T 1991 Evaluation of adhesion formation after laparoscopic treatment of polycystic ovarian disease. Fertil Steril 56:1176–1178[Medline]
  15. Saravelos H, Li TC 1996 Post-operative adhesions after laparoscopic electrosurgical treatment for polycystic ovarian syndrome with the application of Interceed to one ovary: a prospective randomized controlled study. Hum Reprod 11:992–997[Abstract/Free Full Text]
  16. Nestler JE, Jakubowicz DJ, Evans WS, Pasquali R 1998 Effects of metformin on spontaneous and clomiphene-induced ovulation in the polycystic ovary syndrome. N Engl J Med 338:1876–1880[Abstract/Free Full Text]
  17. Homburg R 2002 Should patients with polycystic ovarian syndrome be treated with metformin? A note of cautious optimism. Hum Reprod 17:853–856[Abstract/Free Full Text]
  18. Lord JM, Flight IH, Norman RJ 2003 Insulin-sensitising drugs (metformin, troglitazone, rosiglitazone, pioglitazone, D-chiro-inositol) for polycystic ovary syndrome. Cochrane Database Syst Rev 3:CD003053
  19. Malkawi HY, Qublan HS, Hamaideh AH 2003 Medical vs. surgical treatment for clomiphene citrate-resistant women with polycystic ovary syndrome. J Obstet Gynaecol 23:289–293
  20. Heiat A 2003 Impact of age on definition of standards for ideal weight. Prev Cardiol 6:104–107[Medline]
  21. Modan M, Harris MI, Halkin H 1989 Evaluation of WHO and NDDG criteria for impaired glucose tolerance. Results from two national samples. Diabetes 38:1630–1635[Abstract]
  22. Ferriman D, Gallwey JD 1961 Clinical assessment of body hair growth in women. J Clin Endocrinol Metab 21:1440–1447
  23. Palomba S, Orio Jr F, Colao A, Di Carlo C, Sena T, Lombardi G, Zullo F, Mastrantonio P 2002 Effect of estrogen replacement plus low-dose alendronate treatment on bone density in surgically postmenopausal women with osteoporosis. J Clin Endocrinol Metab 87:1502–1508[Abstract/Free Full Text]
  24. Glueck CJ, Wang P, Fontaine R, Tracy T, Sieve-Smith L 1999 Metformin-induced resumption of normal menses in 39 of 43 (91%) previously amenorrheic women with the polycystic ovary syndrome. Metabolism 48:511–519[CrossRef][Medline]
  25. Glueck CJ, Phillips H, Cameron D, Sieve-Smith L, Wang P 2001 Continuing metformin throughout pregnancy in women with polycystic ovary syndrome appears to safely reduce first-trimester spontaneous abortion: a pilot study. Fertil Steril 75:46–52[CrossRef][Medline]
  26. Glueck CJ, Goldenberg N, Wang P, Loftspring M, Sherman A 2004 Metformin during pregnancy reduces insulin, insulin resistance, insulin secretion, weight, testosterone and development of gestational diabetes: prospective longitudinal assessment of women with polycystic ovary syndrome from preconception throughout pregnancy. Hum Reprod 19:510–521[Abstract/Free Full Text]
  27. Tulandi T 1999 Laparoscopic treatment of polycystic ovarian syndrome. In: Tulandi T, ed. Atlas of laparoscopic and hysteroscopic techniques for gynecologists. London: WB Saunders; 93–95
  28. Pellicano M, Bramante S, Cirillo D, Palomba S, Bifulco G, Zullo F, Nappi C 2003 Effectiveness of autocrosslinked hyaluronic acid gel after laparoscopic myomectomy in infertile patients: a prospective, randomized, controlled study. Fertil Steril 80:441–444[CrossRef][Medline]
  29. Orio Jr F, Palomba S, Di Biase S, Colao A, Tauchmanovà L, Savastano S, Labella D, Russo T, Zullo F, Lombardi G 2003 Homocysteine levels and C677T polymorphism of methylenetetrahydrofolate reductase in women with polycystic ovary syndrome. J Clin Endocrinol Metab 88:673–679[Abstract/Free Full Text]
  30. Morley JE, Patrick P, Perry III HM 2002 Evaluation of assays available to measure free testosterone. Metabolism 51:554–559[CrossRef][Medline]
  31. Tai MM 1994 A mathematical model for the determination of total area under glucose tolerance and other metabolic curves. Diabetes Care 17:152–154[Abstract]
  32. 1985 Revised American Fertility Society classification of endometriosis. Fertil Steril 43:351–352[Medline]
  33. Gleicher N 2000 Cost-effective infertility care. Hum Reprod Update 6:190–199[Abstract/Free Full Text]
  34. Wang CF, Gemzell C 1980 The use of human gonadotropins for the induction of ovulation in women with polycystic ovarian disease. Fertil Steril 33:479–486[Medline]
  35. Garcea N, Campo S, Panetta V, Venneri M, Siccardi P, Dargenio R, De Tomasi F 1985 Induction of ovulation with purified urinary follicle-stimulating hormone in patients with polycystic ovarian syndrome. Am J Obstet Gynecol 151:635–640[Medline]
  36. Neyro JL, Barrenetxea G, Montoya F, Rodriguez-Escudero 1991 Pure FSH for ovulation induction in patients with polycystic ovary syndrome and resistant to clomiphene citrate therapy. Hum Reprod 6:218–221[Abstract/Free Full Text]
  37. Abdel Gadir A, Mowafi RS, Alnaser HM, Alrashid AH, Alonezi OM, Shaw RW 1990 Ovarian electrocautery versus human menopausal gonadotrophins and pure follicle stimulating hormone therapy in the treatment of patients with polycystic ovarian disease. Clin Endocrinol (Oxf) 33:585–592[Medline]
  38. Naether OG, Baukloh V, Fisher R, Kowalczyk T 1994 Long-term follow-up in 206 infertility patients with polycystic ovarian syndrome after laparoscopic electrocautery of the ovarian surface. Hum Reprod 9:2342–2349[Abstract/Free Full Text]
  39. Amer SA, Banu Z, Li TC, Cooke ID 2002 Long-term follow-up of patients with polycystic ovary syndrome after laparoscopic ovarian drilling: endocrine and ultrasonographic outcomes. Hum Reprod 17:2851–2857[Abstract/Free Full Text]
  40. Kriplani A, Manchanda R, Agarwal N, Nayar B 2001 Laparoscopic ovarian drilling in clomiphene citrate-resistant women with polycystic ovary syndrome. J Am Assoc Gynecol Laparosc 8:511–518[CrossRef][Medline]
  41. Gjonnaess H 1998 Late endocrine effects of ovarian electrocautery in women with polycystic ovary syndrome. Fertil Steril 69:697–701[CrossRef][Medline]
  42. Lemieux S, Lewis GF, Ben-Chetrit A, Steiner G, Greenblatt EM 1999 Correction of hyperandrogenemia by laparoscopic ovarian cautery in women with polycystic ovarian syndrome is not accompanied by improved insulin sensitivity or lipid-lipoprotein levels. J Clin Endocrinol Metab 84:4278–4282[Abstract/Free Full Text]
  43. Tulandi T, Saleh A, Morris D, Jacobs HS, Payne NN, Tan SL 2000 Effects of laparoscopic ovarian drilling on serum vascular endothelial growth factor and on insulin responses to the oral glucose tolerance test in women with polycystic ovary syndrome. Fertil Steril 74:585–588[CrossRef][Medline]
  44. Saleh A, Morris D, Tan SL, Tulandi T 2001 Effects of laparoscopic ovarian drilling on adrenal steroids in polycystic ovary syndrome patients with and without hyperinsulinemia. Fertil Steril 75:501–504[CrossRef][Medline]
  45. Velazquez EM, Mendoza S, Hamer T, Sosa F, Glueck CJ 1994 Metformin therapy in polycystic ovary syndrome reduces hyperinsulinemia, insulin resistance, hyperandrogenemia, and systolic blood pressure, while facilitating normal menses and pregnancy. Metabolism 43:647–654[CrossRef][Medline]
  46. Velazquez EM, Acosta A, Mendoza S 1997 Menstrual cyclicity after metformin therapy in polycystic ovary syndrome. Obstet Gynecol 90:392–395[Abstract]
  47. Kolodziejczk B, Duleba AJ, Spaczynski RZ, Pawelczyk L 2000 Metformin therapy decreases hyperandrogenism and hyperinsulinemia in women with polycystic ovary syndrome. Fertil Steril 73:1149–1154[CrossRef][Medline]
  48. Morin-Papunen LC, Koivunen RM, Ruokonen A, Martikainen HK 1998 Metformin therapy improves the menstrual pattern with minimal endocrine and metabolic effects with polycystic ovary syndrome. Fertil Steril 69:691–696[CrossRef][Medline]
  49. Diamanti-Kandarakis E, Kouli C, Tsianateli T, Bergiele A 1998 Therapeutic effects of metformin on insulin resistance and hyperandrogenism in polycystic ovary syndrome. Eur J Endocrinol 138:269–274[Abstract]
  50. Unluhizarci K, Kelestimur F, Bayram F, Sahin Y, Tutus A 1999 The effects of metformin on insulin resistance and ovarian steroidogenesis in women with polycystic ovary syndrome. Clin Endocrinol (Oxf) 51:231–236[CrossRef][Medline]
  51. Pirwany IR, Yates RWS, Cameron IT, Fleming R 1999 Effects of the insulin sensitizing drug metformin on ovarian function, follicular growth and ovulation rate in obese women with oligomenorrhea. Hum Reprod 14:2963–2968[Abstract/Free Full Text]
  52. Moghetti P, Castello R, Negri C, Tosi F, Perrone F, Caputo M, Zanolin E, Muggeo M 2000 Metformin effects on clinical features, endocrine and metabolic profiles, and insulin sensitivity in polycystic ovary syndrome: a randomized, double-blind, placebo-controlled 6-month trial, followed by open, long-term clinical evaluation. J Clin Endocrinol Metab 85:139–146[Abstract/Free Full Text]
  53. Fleming R, Hopkinson ZE, Wallace AM, Greer IA, Sattar N 2002 Ovarian function and metabolic factors in women with oligomenorrhea treated with metformin in a randomized double blind placebo-controlled trial. J Clin Endocrinol Metab 87:569–574[Abstract/Free Full Text]
  54. Vandermolen DT, Ratts VS, Evans WS, Stovall DW, Kauma SW, Nestler JE 2001 Metformin increases the ovulatory rate and pregnancy rate from clomiphene citrate in patients with polycystic ovary syndrome who are resistant to clomiphene citrate alone. Fertil Steril 75:310–315[CrossRef][Medline]
  55. George SS, George K, Irwin C, Job V, Selvakumar R, Jeyaseelan V, Seshadri MS 2003 Sequential treatment of metformin and clomiphene citrate in clomiphene-resistant women with polycystic ovary syndrome: a randomized, controlled trial. Hum Reprod 18:299–304[Abstract/Free Full Text]
  56. De Leo V, la Marca A, Ditto A, Morgante G, Cianci A 1999 Effects of metformin on gonadotropin-induced ovulation in women with polycystic ovary syndrome. Fertil Steril 72:282–285[CrossRef][Medline]
  57. Stadtmauer LA, Toma SK, Riehl RM, Talbert LM 2001 Metformin treatment of patients with polycystic ovary syndrome undergoing in vitro fertilization improves outcomes and is associated with modulation of the insulin-like growth factors. Fertil Steril 75:505–509[CrossRef][Medline]
  58. Yarali H, Yildiz B, Demirol A, Zeyneloglu HB, Yigit N, Bukulmez O, Koray Z 2002 Co-administration of metformin during rFSH treatment in patients with clomiphene citrate-resistant polycystic ovarian syndrome: a prospective randomized trial. Hum Reprod 17:289–294[Abstract/Free Full Text]
  59. Stadtmauer LA, Toma SK, Riehl RM, Talbert LM 2002 Impact of metformin therapy on ovarian stimulation and outcome in ‘coasted’ patients with polycystic ovary syndrome undergoing in-vitro fertilization. Reprod Biomed Online 5:112–116[Medline]
  60. Nestler JE, Jakubowicz DJ 1997 Lean women with polycystic ovary syndrome respond to insulin reduction with decreases in ovarian P450c17{alpha} activity and serum androgens. J Clin Endocrinol Metab 82:4075–4079[Abstract/Free Full Text]
  61. Ng EH, Wat NM, Ho PC 2001 Effects of metformin on ovulation rate, hormonal and metabolic profiles in women with clomiphene-resistant polycystic ovaries: a randomized, double-blinded placebo-controlled trial. Hum Reprod 16:1625–1631[Abstract/Free Full Text]
  62. Dunaif A, Segal KR, Futterweit W, Dobrjansky A 1989 Profound peripheral insulin resistance, independent of obesity, in polycystic ovary syndrome. Diabetes 38:1165–1174[Abstract]
  63. Morin-Papunen L, Vauhkonen I, Koivunen R, Ruokonen A, Martikainen H, Tapanainen JS 2003 Metformin versus ethinyl estradiol-cyproterone acetate in the treatment of nonobese women with polycystic ovary syndrome: a randomized study. J Clin Endocrinol Metab 88:148–156[Abstract/Free Full Text]
  64. Ehrmann DA, Cavaghan MK, Imperial J, Sturis J, Rosenfield RL, Polonsky KS 1997 Effects of metformin on insulin secretion, insulin action, and ovarian steroidogenesis in women with polycystic ovary syndrome. J Clin Endocrinol Metab 82:524–530[Abstract/Free Full Text]
  65. Clark AM, Ledger W, Galletly C, Tomlinson L, Blaney F, Wang X, Norman RJ 1995 Weight loss results in significant improvement in pregnancy and ovulation rates in anovulatory obese women. Hum Reprod 10:2705–2712[Abstract/Free Full Text]
  66. Clark AM, Thornley B, Tomlinson L, Galletley C, Norman RJ 1998 Weight loss in obese infertile women results in improvement in reproductive outcome for all forms of fertility treatment. Hum Reprod 13:1502–1505[Abstract/Free Full Text]
  67. Crosignani PG, Colombo M, Vegetti W, Somigliana E, Gessati A, Ragni G 2003 Overweight and obese anovulatory patients with polycystic ovaries: parallel improvements in anthropometric indices, ovarian physiology and fertility rate induced by diet. Hum Reprod 18:1928–3192[Abstract/Free Full Text]
  68. Balen AH, Tan SL, MacDougall J, Jacobs HS 1993 Miscarriage rates following in-vitro fertilization are increased in women with polycystic ovaries and reduced by pituitary desensitization with buserelin. Hum Reprod 8:959–964[Abstract/Free Full Text]
  69. Homburg R, Armar NA, Eshel A, Adams J, Jacobs HS 1998 Influence of serum luteinising hormone concentrations on ovulation, conception, and early pregnancy loss in polycystic ovary syndrome. BMJ 297:1024–1026
  70. Regan L, Owen EJ, Jacob HS 1990 Hypersecretion of luteinising hormone, infertility, and miscarriage. Lancet 336:1141–1144[CrossRef][Medline]
  71. Sagle M, Bishop K, Ridley N, Alexander FM, Michel M, Bonney RC, Beard RW, Franks S 1988 Recurrent early miscarriage and polycystic ovaries. BMJ 297:1027–1028
  72. Watson H, Kiddy DS, Hamilton-Fairley D, Scanlon MJ, Barnard C, Collins WP, Bonney RC, Franks S 1993 Hypersecretion of luteinizing hormone and ovarian steroids in women with recurrent early miscarriage. Hum Reprod 8:829–833[Abstract/Free Full Text]
  73. Gray RH, Wu LY 2000 Subfertility and risk of spontaneous abortion. Am J Public Health 90:1452–1454[Abstract/Free Full Text]
  74. Regan L, Braude PR, Trembath PL 1989 Influence of past reproductive performance on risk of spontaneous abortion. BMJ 299:541–545
  75. Clifford K, Rai R, Watson H, Regan L 1994 An informative protocol for the investigation of recurrent miscarriage: preliminary experience of 500 consecutive cases. Hum Reprod 9:1328–1332[Abstract/Free Full Text]
  76. Liddell HS, Sowden K, Farquhar CM 1997 Recurrent miscarriage: screening for polycystic ovaries and subsequent pregnancy outcome. Aust NZ J Obstet Gynaecol 37:402–406[Medline]
  77. Jakubowicz DJ, Iuorno MJ, Jakubowicz S, Roberts KA, Nestler JE 2002 Effects of metformin on early pregnancy loss in the polycystic ovary syndrome. J Clin Endocrinol Metab 87:524–529[Abstract/Free Full Text]
  78. Jakubowicz DJ, Iuorno MJ, Jakubowicz S, Roberts KA, Nestler JE, Metformin reduces early pregnancy loss in polycystic ovary syndrome. Program of the 83rd Annual Meeting of The Endocrine Society, Denver, CO, 2001, p 384 (Abstract P2-147).
  79. Kocak M, Caliskan E, Simsir C, Haberal A 2002 Metformin therapy improves ovulatory rates, cervical scores, and pregnancy rates in clomiphene citrate-resistant women with polycystic ovary syndrome. Fertil Steril 77:101–106[Medline]
  80. Mansfield R, Galea R, Brincat M, Hole D, Mason H 2003 Metformin has direct effects on human ovarian steroidogenesis. Fertil Steril 79:956–962[CrossRef][Medline]
  81. Nestler JE, Stovall D, Akhter N, Iuorno MJ, Jakubowicz DJ 2002 Strategies for the use of insulin-sensitizing drugs to treat infertility in women with polycystic ovary syndrome. Fertil Steril 77:209–215[CrossRef][Medline]
  82. Kovacs GT, Clarke S, Burger HG, Healy DL, Vollenhoven B 2002 Surgical or medical treatment of polycystic ovary syndrome: a cost-benefit analysis. Gynecol Endocrinol 16:53–55[Medline]



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