Effects of clomiphene citrate on episodic luteinizing hormone secretion throughout the menstrual cycle

Clomiphene and other antioestrogens for ovulation induction in polycystic ovarian syndrome

BACKGROUND

Subfertility due to anovulation is a common problem in women. First-line oral treatment is with antioestrogens such as clomiphene citrate, but resistance may be apparent with clomiphene. Alternative and adjunctive treatments have been used including tamoxifen, dexamethasone, and bromocriptine. The effectiveness of these is to be determined.

OBJECTIVES

To determine the relative effectiveness of antioestrogen agents including clomiphene alone or in combination with other medical therapies in women with subfertility associated with anovulation, possibly caused by polycystic ovarian syndrome.

SEARCH METHODS

We conducted a search of the Cochrane Gynaecology and Fertility Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, and CINAHL (all from inception to August 2016) to identify relevant randomised controlled trials (RCTs). We searched the United Kingdom National Institute for Clinical Excellence (NICE) guidelines and the references of relevant reviews and RCTs. We also searched the clinical trial registries for ongoing trials (inception until August 2016).

SELECTION CRITERIA

We considered RCTs comparing oral antioestrogen agents for ovulation induction (alone or in conjunction with medical therapies) in anovulatory subfertility. We excluded insulin-sensitising agents, aromatase inhibitors, and hyperprolactinaemic infertility.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed data extraction and quality assessment. The primary outcome was live birth; secondary outcomes were pregnancy, ovulation, miscarriage, multiple pregnancy, ovarian hyperstimulation syndrome, and adverse effects.

MAIN RESULTS

This is a substantive update of a previous review. We identified an additional 13 studies in the 2016 update. The review now includes 28 RCTs (3377 women) and five RCTs awaiting classification. Five of the 28 included trials reported live birth/ongoing pregnancy. Secondary outcomes were poorly reported.The quality of the evidence ranged from low to very low. The primary reasons for downgrading the evidence were imprecision and risk of bias associated with poor reporting. Antioestrogen versus placebo Live birth rate, miscarriage rate, multiple pregnancy rate, and ovarian hyperstimulation syndrome (OHSS)No data were reported for these outcomes. Clinical pregnancy rateClomiphene citrate was associated with an increased chance of a clinical pregnancy compared with placebo, though the size of the benefit was very uncertain (odds ratio (OR) 5.91, 95% confidence interval (CI) 1.77 to 19.68; 3 studies; 133 women; low-quality evidence). If the chance of a clinical pregnancy was 5% in the placebo group, then between 8% and 50% of women would have a clinical pregnancy in the clomiphene group. Clomiphene citrate versus tamoxifen Live birth rateThere was no clear evidence of a difference in the chance of a live birth between the clomiphene citrate and tamoxifen groups (OR 1.24, 95% CI 0.59 to 2.62; 2 studies; 195 women; low-quality evidence). If 20% of women in the tamoxifen group had a live birth, then between 13% and 40% of women in the clomiphene citrate group would have a live birth. Miscarriage rateThere was no clear evidence of a difference in the chance of a miscarriage between the clomiphene citrate and tamoxifen groups (OR 1.81, 95% CI 0.80 to 4.12; 4 studies; 653 women; low-quality evidence). If 3% of women in the tamoxifen group had a miscarriage, then between 2% and 10% in the clomiphene citrate group would have a miscarriage. Clinical pregnancy rateThere was no clear evidence of a difference in the chance of a clinical pregnancy between the clomiphene citrate and tamoxifen groups (OR 1.30, 95% CI 0.92 to 1.85; 5 studies; 757 women; I² = 69%; low-quality evidence). If 22% of women in the tamoxifen group had a clinical pregnancy, then between 21% and 35% in the clomiphene citrate group would have a clinical pregnancy. Multiple pregnancy rate There was insufficient evidence of a difference in the chance of a multiple pregnancy between the clomiphene citrate group (OR 2.34, 95% CI 0.34 to 16.04; 3 studies; 567 women; very low-quality evidence). If 0% of women in the tamoxifen group had a multiple pregnancy, then between 0% and 0.5% of women in the clomiphene group would have a multiple pregnancy. OHSSThere were no instances of OHSS in either the clomiphene citrate or the tamoxifen group reported from three studies. Clomiphene citrate with tamoxifen versus tamoxifen alone Clinical pregnancy rateThere was insufficient evidence to determine whether there was a difference between groups (OR 3.32, 95% CI 0.12 to 91.60; 1 study; 20 women; very low-quality evidence). No data were reported for the other outcomes. Other comparisons of interestLimited evidence suggested that compared with a gonadotropin, clomiphene citrate was associated with a reduced chance of a pregnancy, ongoing pregnancy, or live birth, with no clear evidence of a difference in multiple pregnancy rates.The comparison of clomiphene citrate plus medical adjunct versus clomiphene alone was limited by the number of trials reporting the comparison and poor reporting of clinical outcomes relevant to this systematic review and by the number of adjuncts reported (ketoconazole, bromocriptine, dexamethasone, combined oral contraceptive, human chorionic gonadotropin, hormone supplementation). The addition of dexamethasone or combined oral contraceptive suggested a possible benefit in pregnancy outcomes, but findings were very uncertain and further research is required to confirm this.There was limited evidence suggesting that a 10-day regimen of clomiphene citrate improves pregnancy outcomes compared with a 5-day regimen. Data for early versus late regimens of clomiphene citrate were insufficient to be able to make a judgement on differences for pregnancy outcomes.

AUTHORS' CONCLUSIONS

We found evidence suggesting that clomiphene citrate improves the chance of a clinical pregnancy compared with placebo, but may reduce the chance of live birth or ongoing pregnancy when compared with a gonadotropin. Due to low event rates, we advise caution interpreting these data.The comparison of clomiphene citrate plus medical adjunctive versus clomiphene alone was limited by the number of trials reporting the comparison. The evidence was very low quality and no firm conclusions could be drawn, but very limited evidence suggested a benefit from adjunctive dexamethasone or combined oral contraceptives. Low-quality evidence suggested that a 10-day regimen of clomiphene citrate improves pregnancy rates compared with a 5-day regimen, but further research is required.

Clomiphene and anti-oestrogens for ovulation induction in PCOS

BACKGROUND

Subfertility due to anovulation is a common problem in women. First-line oral treatment is with anti-oestrogens, for example clomiphene citrate, but resistance (failure to ovulate) may be apparent with clomiphene. Alternative and adjunctive treatments have been developed such as tamoxifen, dexamethasone, and bromocriptine.

OBJECTIVES

To determine the relative effectiveness of anti-oestrogen agents alone or in combination with other medical therapies in women with subfertility associated with anovulation, possibly caused by polycystic ovarian syndrome (PCOS).

SEARCH STRATEGY

A search was conducted using the Cochrane Menstrual Disorders and Subfertility Group Trials Register (May 2009), CENTRAL (The Cochrane Library 2009, Issue 2), MEDLINE (1966 to May 2009), and EMBASE (1980 to May 2009) for identification of relevant randomised controlled trials (RCTs). The United Kingdom National Institute for Clinical Excellence (NICE) guidelines and the references of relevant reviews and RCTs were searched.

SELECTION CRITERIA

RCTs comparing oral anti-oestrogen agents for ovulation induction (alone or in conjunction with medical therapies) in anovulatory subfertility were considered. Insulin sensitising agents, aromatase inhibitors, and hyperprolactinaemic infertility were excluded.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment were done independently by two review authors. The primary outcome was live birth; secondary outcomes were pregnancy, ovulation, miscarriage, multiple pregnancy, overstimulation, ovarian hyperstimulation syndrome, and women reported adverse effects.

MAIN RESULTS

This is a substantive update of a previous review. Fifteen RCTs were included. One trial reported live birth. Miscarriage, multiple pregnancy rates and adverse events were poorly reported.Clomiphene was effective in increasing pregnancy rate compared to placebo (OR 5.8, 95% CI 1.6 to 21.5) as was clomiphene plus dexamethasone treatment (OR 9.46, 95% CI 5.1 to 17.7) compared to clomiphene alone. No evidence of a difference in effect was found between clomiphene versus tamoxifen or clomiphene in conjunction with human chorionic gonadotrophin (hCG) versus clomiphene alone.The remaining results had only one study in each comparison. A significant improvement in the pregnancy rate was reported for clomiphene plus combined oral contraceptives versus clomiphene alone. No evidence of a difference in effect on pregnancy rate was found with any of the other comparisons.

AUTHORS' CONCLUSIONS

This review shows evidence supporting the effectiveness of clomiphene citrate and clomiphene in combination with dexamethasone for pregnancy rate only. There is limited evidence on the effects of these drugs on outcomes such as miscarriage. Evidence in favour of these interventions is flawed due to the lack of evidence on live births.

Oral anti-oestrogens and medical adjuncts for subfertility associated with anovulation

BACKGROUND

Infertility due to anovulation is a common problem in women. The first line oral treatment is with anti-oestrogens, such as clomiphene citrate. Unfortunately there may be resistance and alternative and adjunctive treatments have been developed. These include tamoxifen, dexamethasone, bromocriptine and aromatase inhibitors (AIs).

OBJECTIVES

To determine the relative effectiveness of anti-oestrogen agents, with or without medical adjuncts, in women with WHO group 2 anovulation.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group trial register (searched 5th July 2004), CENTRAL (The Cochrane Library Issue 2 2004), MEDLINE (1966 to June 2004) and EMBASE (1980 to June 2004) for identification of relevant randomised controlled trials (RCTs). Additionally the United Kingdom National Institute for Clinical Excellence (NICE) guidelines and the references of relevant reviews and RCTs were searched.

SELECTION CRITERIA

RCTs that compare oral anti-oestrogen agents for ovulation induction (alone or in conjunction with medical adjuncts) in anovulatory subfertility, were considered for inclusion in the review. Metformin and other insulin sensitizing agents were not included. Hyperprolactinaemic infertility was not included.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment was done independently by two reviewers. The primary outcome was live birth, secondary outcomes were: pregnancy, ovulation, miscarriage, multiple pregnancy, overstimulation, ovarian hyperstimulation syndrome and patient reported adverse effects.

MAIN RESULTS

Twelve RCTs were found and included in this review. No trials reported live birth as an outcome. Miscarriage and multiple pregnancy rates were poorly reported. Clomiphene was shown to be effective in increasing pregnancy rate when compared to placebo (fixed OR 5.8, 95% CI 1.6 to 21.5; NNT 5.9, 95% CI 3.6 to 16.7). No evidence of a difference in effect was found between clomiphene and tamoxifen (fixed OR 1.0, 95% CI 0.5 to 2.1). The use of clomiphene in combination with tamoxifen did not find any evidence of effect on pregnancy rate when compared to clomiphene alone (fixed OR 3.3, 95% CI 0.1 to 91.6). The comparison between two AIs (letrozole and anastrozole) did not find any evidence of a difference in effect on pregnancy rate (fixed OR 1.9, 95% CI 0.4 to 8.9). For the intervention of clomiphene plus ketoconazole vs clomiphene no evidence of a difference in effect for pregnancy rate was found (fixed OR 2.4, 95% CI 0.9 to 6.4). For clomiphene plus bromocriptine vs clomiphene no evidence of a difference in effect on pregnancy rate was found (fixed OR 1.0, 95% CI 0.3 to 3.0) rates. However, clomiphene plus dexamethasone treatment resulted in a significant improvement in the pregnancy rate (fixed OR 11.3, 95% CI 5.3 to 24.0; NNT 2.7, 95% CI 2.1 to 3.6) when compared to clomiphene alone as did clomiphene plus pretreatment with combined oral contraceptives (fixed OR 27.2, 95% CI 3.1 to 235.0; NNT 2.0, 95% CI 1.4 to 3.4).

AUTHORS' CONCLUSIONS

This review shows evidence supporting the effectiveness of the current first line treatment, clomiphene citrate. No evidence of a difference in effect was found between clomiphene and tamoxifen. The use of dexamethasone as an adjunct to clomiphene therapy appears promising as do combined oral contraceptives. This review has highlighted a gap in the literature on effects of these drugs on outcomes such as miscarriage rate. Evidence in favour of these interventions is flawed. RCTs of adequate power and of high methodological quality are required for the older treatments such as clomiphene, alone and with medical adjuncts, and also for the newer drugs such as the AIs.

Effect of clomiphene citrate on follicular and luteal phase luteinizing hormone concentrations in in vitro fertilization cycles stimulated with gonadotropins and gonadotropin-releasing hormone antagonist

OBJECTIVE

To investigate the effect that clomiphene citrate exerts on luteinizing hormone (LH) concentrations in gonadotropin/gonadotropin-releasing hormone (GnRH) antagonist cycles.

DESIGN

Retrospective analysis.

SETTING

Tertiary referral center.

PATIENT(S)

Two groups of patients undergoing in vitro fertilization (IVF) were compared. In group I, 20 patients were stimulated with clomiphene citrate (CC) in combination with gonadotropins and 0.25 mg of Cetrorelix (ASTA Medica AG; Frankfurt am Main, Germany) and in group II, 20 patients were stimulated with gonadotropins and 0.25 mg of Cetrorelix.

INTERVENTION(S)

Blood sampling was performed in the late follicular, periovulatory, early, mid, and late luteal phases.

MAIN OUTCOME MEASURE(S)

Luteinizing hormone (LH), estradiol, and progesterone.

RESULT(S)

LH levels were significantly higher in group I than in group II on all the days studied. Progesterone serum concentrations were significantly higher in group II in the early luteal phase, but not in the follicular or the middle and late luteal phases.

CONCLUSION(S)

LH concentrations are significantly higher in the follicular and luteal phases in cycles stimulated with CC, despite GnRH antagonist administration. This observation might have implications for the dose of GnRH antagonist needed to suppress LH in the follicular phase and questions the need for luteal-phase supplementation in cycles in which CC was used.

Decline in insulin-like growth factor I levels after clomiphene citrate does not correct hyperandrogenemia in polycystic ovary syndrome

It is widely accepted that the action of clomiphene citrate (CC) is mediated through its antiestrogenic properties on the hypothalamic-pituitary axis. Although insulin-like growth factor I (IGF-I) enhances the thecal cell response to LH, and estrogen treatment is associated with a reduction in IGF-I levels, CC is known to decrease circulatory IGF-I levels in polycystic ovary syndrome (PCOS) patients. The impact of lowering IGF-I levels on androgen levels in PCOS is unknown. This study was designed to examine the impact of CC treatment on the interrelationships of IGF-I, androgens, and estrogens in normal subjects and patients with PCOS. IGF-I, gonadotropin, androgen, estrogen, and sex hormone-binding globulin levels were measured in 8 PCOS patients and 10 normal subjects before and after treatment with the antiestrogen CC. Studies were performed in the early follicular phase, days 4-6 of the menstrual cycle in normal subjects. In normal subjects, CC treatment led to a significant increase in estradiol (84 +/- 10 to 234 +/- 62 pmol/L, untreated and CC treated; P < 0.05) and estrone (125 +/- 14 to 257 +/- 29 pmol/L; P < 0.05) levels with a significant lowering of IGF-I levels (297 +/- 25 to 230 +/- 17 micrograms/L; P < 0.05). Similarly, in PCOS patients a significant increase in estradiol (110 +/- 11 to 245 +/- 58 pmol/L; P < 0.05) and estrone (301 +/- 32 to 401 +/- 90 pmol/L; P < 0.05) levels and a significant lowering of IGF-I levels (330 +/- 43 to 214 +/- 27 micrograms/L; P < 0.05) were observed after CC treatment. However, no significant correlation was observed between changes in IGF-I and changes in estradiol in either group. Compared to pretreatment levels, no significant changes in the following parameters were observed after 5 days of CC treatment in either study group: testosterone, testosterone/sex hormone-binding globulin ratio, and androstenedione. The relationship among CC treatment, gonadotropin, estrogen, and IGF-I levels is complex. Changes in blood IGF-I levels are not associated with changes in androgen levels, although paracrine and or autocrine effects cannot be excluded.

WITHDRAWN: Clomiphene citrate for ovulation induction in women with oligo-amenorrhoea

BACKGROUND

The administration of clomiphene citrate is followed by an enhanced release of pituitary gonadotropins resulting in follicular recruitment. After the drug is stopped, there is continuing secretion of estradiol, selection of the dominant follicle and, in successful cases, ovulation. Clomiphene is indicated as the initial treatment in the majority of women with amenorrhoea and oligomennorhoea. In women with irregular ovulation it seems to re-establish typical frequency of ovulation. Its effectiveness in oligo-amenorrhoeic women was tested in a number of randomised controlled trials at that time. These trials form the basis for the following review.

OBJECTIVES

Clomiphene citrate enhances the release of pituitary hormones, often resulting in ovulation. The objective of this review was to assess the effects of clomiphene citrate on ovulation and pregnancy in women with oligo-ovulatory subfertility.

SEARCH STRATEGY

The Cochrane Subfertility Review Group specialised register of controlled trials was searched.

SELECTION CRITERIA

Randomised trials of clomiphene compared with placebo or no treatment in women with oligo-ovulatory subfertility of at least 12 months duration.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted independently by two reviewers.

MAIN RESULTS

Four studies were included. They were all of crossover design. Since it was not possible to separate data from the first and second phases of these trials, the effect of clomiphene may be overestimated. Compared with placebo, clomiphene citrate was associated with increased ovulation. The odds ratio for high doses (50-250 milligrams per day) was 6.82 (95% confidence interval 3.92 to 11.85). This dropped to a non-significant odds ratio of 1.29 (95% confidence interval 0.48 to 3.49) with low doses (10 milligrams per day). Clomiphene citrate (all doses) was associated with an increased pregnancy rate per treatment cycle (odds ratio 3.41, 95% confidence interval 4.23 to 9.48).

AUTHORS' CONCLUSIONS

Clomiphene citrate (at doses between 50 to 250 milligrams per day) appears to be an effective method of inducing ovulation and improving fertility in oligo-ovulatory women. However adverse effects include possible ovarian cancer risk and risk of multiple pregnancy.

Clinical uses of antiestrogens

An antiestrogen is a compound that blocks the action of estrogen. Most synthetic antiestrogens have agonistic or antagonistic activity depending on the tissue and the endogenous estrogen mileu. The triphenylethylene derivatives, clomiphene and tamoxifen, are the antiestrogens in greatest clinical use. Their biologic effects, clinical indications, and risks are reviewed. Novel antiestrogens which are beginning to be studied clinically include the benzothiophene derivative, raloxifene and the "pure" antiestrogens such as ICI 182,780. New clinical indications for existing compounds as well as the development of novel antiestrogens may lead to better treatment options for endocrine-dependent conditions.

Gonadotropin pulsatility in a stimulated cycle: clomiphene citrate increases pulse amplitudes of both luteinizing hormone and follicle-stimulating hormone

OBJECTIVE

To elucidate gonadotropin secretory patterns during ovarian hyperstimulation for in vitro fertilization.

DESIGN

All volunteers who attended the unit during a period of 3 months were prospectively investigated.

SETTING

Infertility unit of the University Central Hospital of Oulu.

PARTICIPANTS

Normally menstruating tubal infertility patients (n = 8) and healthy women with ovulatory cycles (hospital personnel, n = 11). All patients finished the study.

INTERVENTIONS

Clomiphene citrate (CC), 50 mg, was administered on cycle days 5 to 9 and 300 IU of pure follicle-stimulating hormone (FSH) on cycle day 7 and 150 IU on cycle day 8.

MAIN OUTCOME MEASURES

Serum samples for luteinizing hormone (LH) and FSH measurements were collected at 10-minute intervals for 6 hours on cycle day 7 (effect of CC) and day 9 (effect of CC/FSH), and the data were analyzed with the Munro computer program.

RESULTS

The number of LH peaks was identical in the controls and study subjects on cycle days 7 and 9, whereas the pulse amplitude (P less than 0.025) and the pulse area (P less than 0.01) were higher in the CC/FSH-treated patients. The increase in overall mean LH level during the hormone therapy was not significant. In the CC/FSH-treated women, a decreased number of FSH pulses (P less than 0.01) with increased amplitude (P less than 0.001) and pulse area (P less than 0.01) was found. Clomiphene citrate treatment increased the mean FSH level (control versus cycle day 7, P less than 0.05) which was further increased (cycle day 7 versus cycle day 9, P less than 0.05) by FSH administration on cycle days 7 to 8. Otherwise pure FSH was found to be unable to modify endogenous LH or FSH secretory patterns under these conditions.

CONCLUSIONS

Clomiphene citrate increases the amplitudes of both LH and FSH pulses in the midfollicular phase of a stimulated cycle, an effect which is not influenced by pure FSH administration.