Effects of metformin on body mass index,menstrual cyclicity,and ovulation induction in women with polycystic ovary syndrome

OBJECTIVE: Metformin has been used as a treatment in many studies of the infertility associated with polycystic ovary syndrome (PCOS). We will review the literature on this topic as it specifically relates to changes in body mass index (BMI), improvement in menstrual cyclicity, and effects on ovulation and pregnancy rates. DESIGN: Review of studies addressing biochemical and clinical changes in women with PCOS on metformin. MAIN OUTCOME MEASURE(S): Changes in BMI, menstrual cyclicity, ovulation rate, and pregnancy rate. RESULT(S): Metformin has been shown to produce small but significant reductions in BMI. Multiple observational studies have confirmed an improvement in menstrual cyclicity with metformin therapy. The studies addressing the concomitant use of metformin with clomiphene citrate initially predicted great success, but these have been followed by more modest results. There is little data in the literature concerning the use of metformin and hMGs. CONCLUSION(S): Some (but not all) women with PCOS have improvements in their menstrual cycles while on metformin. The data supporting the use of metformin in ovulation induction with clomiphene citrate and hMG remain to be confirmed by large, randomized, prospective studies.     

Transvaginal ultrasonography in women receiving emergency contraception

OBJECTIVE: To determine whether transvaginal ultrasonography improves evaluation of conception time in women seeking emergency contraception. DESIGN: Prospective study. SETTING: Obstetrics and Gynecology Department, Siena University, Siena, Italy. PATIENT(S): One hundred sixty-three women seeking postcoital contraception. MAIN OUTCOME MEASURE(S): Data on menstrual history and time of unprotected intercourse were recorded. Ultrasonographic variables evaluated were ovarian follicle or corpus luteum diameter, endometrial echopattern and thickness, and peritoneal fluid volume. Expected pregnancy rates were calculated according to the probability of conception as estimated from Dixon's table of data, based solely on anamnestic data, or from endometrial or ovarian findings on transvaginal ultrasonography. RESULT(S): According to the menstrual history (cut-off level < 0.03) we expected to find 7.6 pregnancies (7.9 in the high-risk group and 0.31 in the low-risk group). According to transvaginal ultrasonography (at the same cut-off), we expected 11.2 pregnancies (0.3 in the low-risk group and 10.9 in the high-risk group). No more than 7 pregnancies were observed, all of which occurred in the high-risk group as determined by transvaginal ultrasonography. In contrast, on the basis of anamnestic data, 4 of 7 pregnancies were in the high-risk group and 3 of 7 were in the low-risk group. CONCLUSION(S): Transvaginal ultrasonography allows timely definition of the fertile period and is a reliable method of computing the day of ovulation. It improves therapeutic options by allowing treatment of only women at high risk of conception.     

Pregnancies following use of metformin for ovulation induction in patients with polycystic ovary syndrome

OBJECTIVE: To assess pregnancy outcome in anovulatory infertility patients diagnosed with polycystic ovary syndrome (PCOS) who were treated with metformin. DESIGN: Case series. SETTING: Outpatient. PATIENT(S): Anovulatory patients (n = 48) with a diagnosis of PCOS based on clinical, diagnostic, and laboratory evaluations were enrolled in the study over a 15-month period. INTERVENTION(S): Metformin was started at 500 mg b.i.d. for 6 weeks and then increased to 500 mg t.i.d. if no ovulation occurred. Clomiphene citrate (CC; 50 mg) was added if no ovulatory response occurred after 6 weeks. MAIN OUTCOME MEASURE(S): Resumption of menses, presumptive ovulation, and pregnancy. RESULT(S): Nineteen of 48 (40%) patients resumed spontaneous menses following treatment and showed presumptive evidence of ovulation with metformin alone; 15/48 (31%) required CC (50 mg) in conjunction with metformin therapy, and 10 of these 15 (67%) had evidence of ovulation; 20/48 (42%) conceived with a median time to conception of 3 months, and 7 of these 20 (35%) had spontaneous abortions (SAB); 19/48 (40%) had gastrointestinal-related side effects, and 5 of 48 patients (10%) had to decrease the dosage of metformin. Only 1 patient discontinued therapy. CONCLUSION(S): Metformin alone in patients with PCOS results in a substantial number of pregnancies, with 69% (20/29) of those who ovulated conceiving in less than 6 months.     

The clinical therapeutic window for luteinizing hormone in controlled ovarian stimulation

Objective: To discuss the clinical therapeutic window for LH during the follicular phase.

Design: Review of selected papers that were retrieved through a Medline search and a review of clinical trials, the results of which are in the process of publication.

Patient(s): Women undergoing infertility treatment.

Intervention(s): Recombinant human LH (r-hLH) was administered SC as a supplement to FSH during controlled ovarian hyperstimulation.

Main Outcome Measure(s): Follicular development, E₂ production, and endometrial thickness.

Result(s): Optimal follicular maturation is the result of both FSH and LH stimulation. In patients with hypogonadotropic hypogonadism, 75 IU of r-hLH and 150 IU of FSH per day resulted in more follicles and provided sufficient E₂ for optimal endometrial proliferation. Additional r-hLH (>250 IU/day), in patients with either hypogonadotropic hypogonadism or polycystic ovary disease, may precipitate a series of deleterious physiological actions leading to atresia of developing follicles. Adding r-hLH to FSH in women treated with GnRH agonist showed no benefits in terms of number of mature oocytes, fertilization, and cleavage. However, those who experience profound pituitary desensitization may benefit from adding LH to the stimulation protocol. No obvious clinical criteria have been established to define this group of patients.

Conclusion(s): A “threshold” and “ceiling” level for LH (therapeutic window) is proposed, below which E₂ production is not adequate and above which LH may be detrimental to follicular development.     

A randomized double-blind comparison of the effects of clomiphene citrate and the aromatase inhibitor letrozole on ovulatory function in normal women

OBJECTIVE: To evaluate the ovarian follicular dynamics of cycle modification with the aromatase inhibitor letrozole compared with clomiphene citrate in normal ovulatory women. DESIGN: Randomized double-blind controlled trial. SETTING: Tertiary care hospital. PATIENT(S): Nineteen ovulatory female volunteers, ages 18-35 years. INTERVENTION(S): Subjects were monitored in one control cycle. Subjects then received either letrozole 2.5 mg daily or clomiphene citrate 50 mg daily on days 5-9 after menses. MAIN OUTCOME MEASURE(S): Number of mature follicles, endometrial thickness and endometrial pattern at ovulation, and follicular profiles of LH, FSH, and E(2). RESULT(S): The number of mature follicles at the LH surge in natural cycles was 1.0 with an exaggerated response seen for treatment both with clomiphene and letrozole. There was no difference in the endometrial thickness at midcycle during either the natural cycles or the medicated cycles. LH surges and spontaneous ovulation were documented in all natural and medicated cycles. When measured daily, follicular profiles of LH and FSH are similar between the groups in both the natural and medicated cycles. In the medicated cycles, clomiphene results in a significant increase in E(2) levels, while E(2) levels in letrozole-stimulated cycles appeared lower than in natural cycles. CONCLUSION(S): Transient inhibition of aromatase activity in the early follicular phase with the aromatase inhibitor letrozole results in stimulation of ovarian folliculogenesis similar to that seen with clomiphene citrate with no apparent adverse effect on endometrial thickness or pattern at midcycle.     

Patient predictors for outcome of gonadotrophin ovulation induction in women with normogonadotrophic anovulatory infertility: a meta-analysis

A systematic review was conducted to determine whether initial screening characteristics of women with normogonadotrophic anovulatory infertility predict clinically significant outcomes of ovulation induction with gonadotrophins, and to obtain pooled estimates of their predictive value through meta-analysis. Only those studies in which pre-treatment screening characteristics (such as body mass index, serum LH and androgens, insulin sensitivity and ultrasound appearance of ovaries) were related to outcome parameters (such as total amount of FSH administered, cancellation, ovulation, pregnancy and miscarriage), were included in this analysis. Thirteen studies fulfilled the inclusion criteria. A positive association was seen in all studies between the level of obesity (definition applied as assessed by individual studies) and total amount of FSH administered [weighted mean difference (WMD) of 771 IU (95% confidence interval (CI): 700-842)]. Pooled odds ratios (OR) of 1.86 (95% CI: 1.13-3.06) and 0.44 (95% CI: 0.31-0.61) were found between obesity with cancellation and ovulation respectively. Pooled analysis did not show a significant association between obesity and pregnancy rate. The pooled OR for obese versus non-obese women and miscarriage rate was significant [3.05 (95% CI: 1.45-6.44)]. Association measures between insulin resistance (definition applied as assessed by individual studies) and total amount of FSH administered produced a WMD of 351 (95% CI: 73-630) IU. A pooled OR of 0.29 (95% CI: 0.10-0.80) was found for insulin resistance with pregnancy rate. The pooled OR for insulin resistance (hyperinsuliaemia versus normoinsuliaemia) and miscarriage rate was not significant. A pooled OR of 1.04 (95% CI: 1.01-1.07) was found for LH (IU/l) with pregnancy rate. The pooled OR for LH and miscarriage rate was not significant. Finally, pooled analysis did not find a significant association between testosterone and pregnancy rate. In conclusion, the best available evidence, though limited, suggests that the most clinically useful predictors of gonadotrophin ovulation induction outcome in normogonadotrophic women are obesity and insulin resistance.     

Follicular administration of a cyclooxygenase inhibitor can prevent oocyte release without alteration of normal luteal function in rhesus monkeys

BACKGROUND: Prostaglandins (PG), produced by the follicle just before ovulation, appear to act locally to promote follicle rupture and oocyte release. METHODS: To determine whether administration of PG synthesis inhibitor directly into the primate follicle would prevent ovulatory events, serum estradiol was used to predict the day of the ovulatory LH surge in rhesus monkeys. On the day before or the day of the LH surge, vehicle (n = 9), the PG synthesis inhibitor indomethacin (10(-6) or 10(-5) mol/l final concentration; n = 8), or 10(-5) mol/l indomethacin + 1 micro g/ml PGE(2) (n = 3) was injected into the follicular fluid of the pre-ovulatory follicle. In some animals, luteal phase estrogen and progesterone were measured in daily serum samples. Other animals were ovariectomized 3 days after follicle injection; ovaries were examined for verification of follicle rupture and oocyte release. RESULTS: Follicle injection of indomethacin [10(-6) mol/l (n = 4) or 10(-5) (n = 4) mol/l final concentration] or vehicle (n = 6) did not alter luteal function. Examination of serial sections of removed ovaries confirmed follicle rupture and the absence of oocytes in vehicle-injected follicles (n = 3). Trapped oocytes were observed in 4/8 indomethacin-injected follicles, though several ovaries with trapped oocytes had experienced follicle rupture. Oocytes were not detected in the ruptured, luteinizing follicles from indomethacin + PGE(2)-injected monkeys (n = 3). CONCLUSIONS: Follicular administration of indomethacin can prevent oocyte release without inhibition of follicle rupture or disruption of subsequent luteal function. The ability of PGE(2) to prevent indomethacin-induced ovulatory failure suggests a critical role for locally produced PGE(2) in the process of oocyte release in primates.     

Ovulation and risk of epithelial ovarian cancer

Incessant ovulation is thought to be one of the primary causes of epithelial ovarian cancer. However, the effects of ovulation at different ages and of the various exposures or events that suppress ovulation have not been established. We used data from an Australian case-control study of 791 ovarian cancer cases and 853 controls to examine the effect of ovulation on ovarian cancer risk. The total number of lifetime ovulations was calculated using information provided in a monthly contraceptive/reproductive calendar, as well as incorporating other information such as average menstrual cycle length. An increase of 1 year's worth of ovulation was associated with a 6% increase in risk of ovarian cancer (95% confidence interval [CI] = 4-8%). Ovulations in the 20-29-year age group were associated with the greatest risk, with a 20% increase in risk associated with each year of ovulation during this age period (95% CI = 13-26%). When the effects of different exposures that suppress ovulation were compared, there was an indication that some factors may have a greater effect than others. These findings support the theory that incessant ovulation is a major contributor to the occurrence of ovarian cancer and suggest that ovulations during the 20s may be those most associated with disease risk.     

小鼠体外成熟与激素超排卵母细胞核型分析

目的：评价激素超排(HIO)和体外培养成熟(CVM)两种方法对小鼠卵母细胞染色体的影响。方法：通过HIO与CVM分别获得100个、80个成熟小鼠卵母细胞,制备染色体标本进行核型分析。结果：在HIO组,超单倍体率、非整倍体率、染色体结构畸变率、结构畸变卵母细胞率、退化卵母细胞率和染色体分离均数依次为2,0％、4．0％、2．0％、2．0％、8．0％和0．13;在CVM组,上述实验参数依次为4．O％、8．O％、7．5％、6．3％、12．5％和O．325;两组所有实验参数经统计学处理没有显著差异。结论：经体外培养成熟的与经激素超排的小鼠卵母细胞其质量和染色体核型没有本质上的差异。将此结果外推到人类,提示未成熟卵母细胞经体外培养成熟在人类辅助生殖领域具有广泛的应用前景。     

Influence of the angiotensinogen gene on the ovulatory capacity of mice

Objective: The tissue-bound ovarian renin-angiotensin system (OVRAS) is critically involved in ovulation in humans and rodents. Mice with disruption and overexpression of the angiotensinogen gene (Agt) have been previously generated. We investigated the influence of varying Agt gene expression on the ovulatory capacity and early embryonic development in mice.

Design: Observational study of genetically altered mice and their response to a superovulation protocol.

Setting: Academic research institution.

Animal(s): Mice with varying copy numbers of Agt (one copy: N = 48; two copies: N = 51; three copies: N = 20; four copies: N = 24).

Intervention(s): Superovulation protocol, oocyte culture.

Main Outcome Measure(s): Number of oocytes harvested, early embryonic development of zygotes, evaluation of ovarian histology, serum estradiol measurements.

Result(s): The mean number of oocytes harvested was greatest in wild-type mice (two copies of Agt, 39.9 ± 14) with a reduction of ovulatory capacity in mice overexpressing Agt (three copies [34.8 ± 11.7] and four copies [31.2 ± 12.4], P = .026). Mice with one copy of Agt showed a slight decrease of ovulatory capacity compared to wild-type mice (35.8 ± 15.2, P = .29). Ovarian histology, serum estradiol levels, and early embryonic development were independent of the Agt genotype.

Conclusion(s): Overexpression of Agt was associated with reduced ovulatory capacity, but with none of the other parameters that were evaluated. These findings support an important role of the ovarian renin-angiotensin system in the process of follicular rupture.