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The Cochrane Database of Systematic... Feb 2020Polycystic ovary syndrome (PCOS) is a common condition affecting 8% to 13% of reproductive-aged women. In the past clomiphene citrate (CC) used to be the first-line... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Polycystic ovary syndrome (PCOS) is a common condition affecting 8% to 13% of reproductive-aged women. In the past clomiphene citrate (CC) used to be the first-line treatment in women with PCOS. Ovulation induction with letrozole should be the first-line treatment according to new guidelines, but the use of letrozole is off-label. Consequently, CC is still commonly used. Approximately 20% of women on CC do not ovulate. Women who are CC-resistant can be treated with gonadotrophins or other medical ovulation-induction agents. These medications are not always successful, can be time-consuming and can cause adverse events like multiple pregnancies and cycle cancellation due to an excessive response. Laparoscopic ovarian drilling (LOD) is a surgical alternative to medical treatment. There are risks associated with surgery, such as complications from anaesthesia, infection, and adhesions.
OBJECTIVES
To evaluate the effectiveness and safety of LOD with or without medical ovulation induction compared with medical ovulation induction alone for women with anovulatory polycystic PCOS and CC-resistance.
SEARCH METHODS
We searched the Cochrane Gynaecology and Fertility Group (CGFG) trials register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL and two trials registers up to 8 October 2019, together with reference checking and contact with study authors and experts in the field to identify additional studies.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) of women with anovulatory PCOS and CC resistance who underwent LOD with or without medical ovulation induction versus medical ovulation induction alone, LOD with assisted reproductive technologies (ART) versus ART, LOD with second-look laparoscopy versus expectant management, or different techniques of LOD.
DATA COLLECTION AND ANALYSIS
Two review authors independently selected studies, assessed risks of bias, extracted data and evaluated the quality of the evidence using the GRADE method. The primary effectiveness outcome was live birth and the primary safety outcome was multiple pregnancy. Pregnancy, miscarriage, ovarian hyperstimulation syndrome (OHSS), ovulation, costs, and quality of life were secondary outcomes.
MAIN RESULTS
This updated review includes 38 trials (3326 women). The evidence was very low- to moderate-quality; the main limitations were due to poor reporting of study methods, with downgrading for risks of bias (randomisation and allocation concealment) and lack of blinding. Laparoscopic ovarian drilling with or without medical ovulation induction versus medical ovulation induction alone Pooled results suggest LOD may decrease live birth slightly when compared with medical ovulation induction alone (odds ratio (OR) 0.71, 95% confidence interval (CI) 0.54 to 0.92; 9 studies, 1015 women; I = 0%; low-quality evidence). The evidence suggest that if the chance of live birth following medical ovulation induction alone is 42%, the chance following LOD would be between 28% and 40%. The sensitivity analysis restricted to only RCTs with low risk of selection bias suggested there is uncertainty whether there is a difference between the treatments (OR 0.90, 95% CI 0.59 to 1.36; 4 studies, 415 women; I = 0%, low-quality evidence). LOD probably reduces multiple pregnancy rates (Peto OR 0.34, 95% CI 0.18 to 0.66; 14 studies, 1161 women; I = 2%; moderate-quality evidence). This suggests that if we assume the risk of multiple pregnancy following medical ovulation induction is 5.0%, the risk following LOD would be between 0.9% and 3.4%. Restricting to RCTs that followed women for six months after LOD and six cycles of ovulation induction only, the results for live birth were consistent with the main analysis. There may be little or no difference between the treatments for the likelihood of a clinical pregnancy (OR 0.86, 95% CI 0.72 to 1.03; 21 studies, 2016 women; I = 19%; low-quality evidence). There is uncertainty about the effect of LOD compared with ovulation induction alone on miscarriage (OR 1.11, 95% CI 0.78 to 1.59; 19 studies, 1909 women; I = 0%; low-quality evidence). OHSS was a very rare event. LOD may reduce OHSS (Peto OR 0.25, 95% CI 0.07 to 0.91; 8 studies, 722 women; I = 0%; low-quality evidence). Unilateral LOD versus bilateral LOD Due to the small sample size, the quality of evidence is insufficient to justify a conclusion on live birth (OR 0.83, 95% CI 0.24 to 2.78; 1 study, 44 women; very low-quality evidence). There were no data available on multiple pregnancy. The likelihood of a clinical pregnancy is uncertain between the treatments, due to the quality of the evidence and the large heterogeneity between the studies (OR 0.57, 95% CI 0.39 to 0.84; 7 studies, 470 women; I = 60%, very low-quality evidence). Due to the small sample size, the quality of evidence is not sufficient to justify a conclusion on miscarriage (OR 1.02, 95% CI 0.31 to 3.33; 2 studies, 131 women; I = 0%; very low-quality evidence). Other comparisons Due to lack of evidence and very low-quality data there is uncertainty whether there is a difference for any of the following comparisons: LOD with IVF versus IVF, LOD with second-look laparoscopy versus expectant management, monopolar versus bipolar LOD, and adjusted thermal dose versus fixed thermal dose.
AUTHORS' CONCLUSIONS
Laparoscopic ovarian drilling with and without medical ovulation induction may decrease the live birth rate in women with anovulatory PCOS and CC resistance compared with medical ovulation induction alone. But the sensitivity analysis restricted to only RCTs at low risk of selection bias suggests there is uncertainty whether there is a difference between the treatments, due to uncertainty around the estimate. Moderate-quality evidence shows that LOD probably reduces the number of multiple pregnancy. Low-quality evidence suggests that there may be little or no difference between the treatments for the likelihood of a clinical pregnancy, and there is uncertainty about the effect of LOD compared with ovulation induction alone on miscarriage. LOD may result in less OHSS. The quality of evidence is insufficient to justify a conclusion on live birth, clinical pregnancy or miscarriage rate for the analysis of unilateral LOD versus bilateral LOD. There were no data available on multiple pregnancy.
Topics: Anovulation; Birth Rate; Female; Fertility Agents, Female; Humans; Infertility, Female; Laparoscopy; Ovulation Induction; Polycystic Ovary Syndrome; Pregnancy; Pregnancy Rate; Randomized Controlled Trials as Topic
PubMed: 32048270
DOI: 10.1002/14651858.CD001122.pub5 -
The Cochrane Database of Systematic... Dec 2019Polycystic ovary syndrome (PCOS) is characterised by infrequent or absent ovulation, and high levels of androgens and insulin (hyperinsulinaemia). Hyperinsulinaemia... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Polycystic ovary syndrome (PCOS) is characterised by infrequent or absent ovulation, and high levels of androgens and insulin (hyperinsulinaemia). Hyperinsulinaemia occurs secondary to insulin resistance and is associated with an increased biochemical risk profile for cardiovascular disease and an increased prevalence of diabetes mellitus. Insulin-sensitising agents such as metformin may be effective in treating PCOS-related anovulation. This is an update of Morley 2017 and only includes studies on metformin.
OBJECTIVES
To evaluate the effectiveness and safety of metformin in combination with or in comparison to clomiphene citrate (CC), letrozole and laparoscopic ovarian drilling (LOD) in improving reproductive outcomes and associated gastrointestinal side effects for women with PCOS undergoing ovulation induction.
SEARCH METHODS
We searched the following databases from inception to December 2018: Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL. We searched registers of ongoing trials and reference lists from relevant studies.
SELECTION CRITERIA
We included randomised controlled trials of metformin compared with placebo, no treatment, or in combination with or compared with CC, letrozole and LOD for women with PCOS subfertility.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed studies for eligibility and bias. Primary outcomes were live birth rate and gastrointestinal adverse effects. Secondary outcomes included other pregnancy outcomes and ovulation. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I statistic and reported quality of the evidence for primary outcomes and reproductive outcomes using GRADE methodology.
MAIN RESULTS
We included 41 studies (4552 women). Evidence quality ranged from very low to moderate based on GRADE assessment. Limitations were risk of bias (poor reporting of methodology and incomplete outcome data), imprecision and inconsistency. Metformin versus placebo or no treatment The evidence suggests that metformin may improve live birth rates compared with placebo (OR 1.59, 95% CI 1.00 to 2.51; I = 0%; 4 studies, 435 women; low-quality evidence). For a live birth rate of 19% following placebo, the live birth rate following metformin would be between 19% and 37%. The metformin group probably experiences more gastrointestinal side effects (OR 4.00, 95% CI 2.63 to 6.09; I = 39%; 7 studies, 713 women; moderate-quality evidence). With placebo, the risk of gastrointestinal side effects is 10% whereas with metformin this risk is between 22% and 40%. There are probably higher rates of clinical pregnancy (OR 1.98, 95% CI 1.47 to 2.65; I = 30%; 11 studies, 1213 women; moderate-quality evidence). There may be higher rates of ovulation with metformin (OR 2.64, 95% CI 1.85 to 3.75; I = 61%; 13 studies, 684 women; low-quality evidence). We are uncertain about the effect on miscarriage rates (OR 1.08, 95% CI 0.50 to 2.35; I = 0%; 4 studies, 748 women; low-quality evidence). Metformin plus CC versus CC alone We are uncertain if metformin plus CC improves live birth rates compared to CC alone (OR 1.27, 95% CI 0.98 to 1.65; I = 28%; 10 studies, 1219 women; low-quality evidence), but gastrointestinal side effects are probably more common with combined therapy (OR 4.26, 95% CI 2.83 to 6.40; I = 8%; 6 studies, 852 women; moderate quality evidence). The live birth rate with CC alone is 24%, which may change to between 23% to 34% with combined therapy. With CC alone, the risk of gastrointestinal side effects is 9%, which increases to between 21% to 37% with combined therapy. The combined therapy group probably has higher rates of clinical pregnancy (OR 1.62, 95% CI 1.32 to 1.99; I = 31%; 19 studies, 1790 women; moderate-quality evidence). The combined group may have higher rates of ovulation (OR 1.65, 95% CI 1.35 to 2.03; I = 63%;21 studies, 1568 women; low-quality evidence). There was no clear evidence of an effect on miscarriage (OR 1.35, 95% CI 0.91 to 2.00; I = 0%; 10 studies, 1206 women; low-quality evidence). Metformin versus CC When all studies were combined, findings for live birth were inconclusive and inconsistent (OR 0.71, 95% CI 0.49 to 1.01; I = 86%; 5 studies, 741 women; very low-quality evidence). In subgroup analysis by obesity status, obese women had a lower birth rate in the metformin group (OR 0.30, 95% CI 0.17 to 0.52; 2 studies, 500 women), while the non-obese group showed a possible benefit from metformin, with high heterogeneity (OR 1.71, 95% CI 1.00 to 2.94; I = 78%, 3 studies, 241 women; very low-quality evidence). However, due to the very low quality of the evidence we cannot draw any conclusions. Among obese women taking metformin there may be lower rates of clinical pregnancy (OR 0.34, 95% CI 0.21 to 0.55; I = 0%; 2 studies, 500 women; low-quality evidence) and ovulation (OR 0.29, 95% CI 0.20 to 0.43; I = 0%; 2 studies, 500 women; low-quality evidence) while among non-obese women, the metformin group may have more pregnancies (OR 1.56, 95% CI 1.06 to 2.29; I = 26%; 6 studies, 530 women; low-quality evidence) and no clear difference in ovulation rates (OR 0.80, 95% CI 0.52 to 1.25; I = 0%; 5 studies, 352 women; low-quality evidence). We are uncertain whether there is a difference in miscarriage rates between the groups (overall: OR 0.92, 95% CI 0.51 to 1.66; I = 36%; 6 studies, 781 women; low-quality evidence) and no studies reported gastrointestinal side effects.
AUTHORS' CONCLUSIONS
Our updated review suggests that metformin may be beneficial over placebo for live birth however, more women probably experience gastrointestinal side effects. We are uncertain if metformin plus CC improves live birth rates compared to CC alone, but gastrointestinal side effects are probably increased with combined therapy. When metformin was compared with CC, data for live birth were inconclusive, and the findings were limited by lack of evidence. Results differed by body mass index (BMI), emphasising the importance of stratifying results by BMI. No studies reported gastrointestinal side effects in this comparison. Due to the low quality of the evidence, we are uncertain of the effect of metformin on miscarriage in all three comparisons.
Topics: Abortion, Spontaneous; Birth Rate; Body Mass Index; Clomiphene; Female; Fertility Agents, Female; Humans; Infertility, Female; Metformin; Ovary; Ovulation Induction; Polycystic Ovary Syndrome; Pregnancy; Pregnancy Outcome; Pregnancy Rate; Randomized Controlled Trials as Topic
PubMed: 31845767
DOI: 10.1002/14651858.CD013505