To study the contribution of ovulation induction and ovarian stimulation, in vitro fertilization (IVF), and unassisted conception to the increase in national plural births in the United States, a ...significant contributor to adverse maternal and infant health outcomes.
National and IVF-assisted plural birth data were derived from the Centers for Disease Control and Prevention's National Vital Statistics System (1967-2021, after introduction of Clomiphene Citrate in the United States) and the National Assisted Reproductive Technology Surveillance System (1997-2021), respectively.
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In addition to IVF-assisted plural births, the contributions of unassisted conception to plural births among women aged <35 and ≥35 years were estimated using plural birth rates from 1949-1966 and a Bayesian logistic model with race and age as independent variables. The contribution of ovulation induction and ovarian stimulation was estimated as the difference between national plural births and IVF-assisted and unassisted counterparts.
From 1967-2021, the national twin birth rate increased 1.7-fold to a 2014 high (33.9/1,000 live births), then declined to 31.2/1,000 live births; the triplet and higher order birth rate increased 6.7-fold to a 1998 high (1.9/1,000 live births), then declined to 0.8/1,000 live births. In 2021, the contribution of unassisted conception among women aged <35 years to the national plural births was 56.1%, followed by ovulation induction and ovarian stimulation (19.5%), unassisted conception among women aged ≥35 years (16.8%), and IVF (7.6%). During 2009-2021, the contribution of ovulation induction and ovarian stimulation has remained stable, the contribution of unassisted conception among women aged <35 and ≥35 years has increased, and the contribution of IVF has decreased.
Ovulation induction and ovarian stimulation are leading iatrogenic contributors to plural births. They are, therefore, targets for intervention to reduce the adverse maternal and infant health outcomes associated with plural births. Maternal age of ≥35 years is a significant contributor to the national plural birth increase.
Background
Gonadotrophin‐releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo‐oestrogenic ...side‐effects, flare‐up, or long down‐regulation period associated with agonists. The antagonists directly and rapidly inhibit gonadotrophin release within several hours through competitive binding to pituitary GnRH receptors. This property allows their use at any time during the follicular phase. Several different regimens have been described including multiple‐dose fixed (0.25 mg daily from day six to seven of stimulation), multiple‐dose flexible (0.25 mg daily when leading follicle is 14 to 15 mm), and single‐dose (single administration of 3 mg on day 7 to 8 of stimulation) protocols, with or without the addition of an oral contraceptive pill. Further, women receiving antagonists have been shown to have a lower incidence of ovarian hyperstimulation syndrome (OHSS). Assuming comparable clinical outcomes for the antagonist and agonist protocols, these benefits would justify a change from the standard long agonist protocol to antagonist regimens. This is an update of a Cochrane review first published in 2001, and previously updated in 2006 and 2011.
Objectives
To evaluate the effectiveness and safety of gonadotrophin‐releasing hormone (GnRH) antagonists compared with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception cycles.
Search methods
We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched from inception to May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, inception to 28 April 2015), Ovid MEDLINE (1966 to 28 April 2015), EMBASE (1980 to 28 April 2015), PsycINFO (1806 to 28 April 2015), CINAHL (to 28 April 2015) and trial registers to 28 April 2015, and handsearched bibliographies of relevant publications and reviews, and s of major scientific meetings, for example the European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM). We contacted the authors of eligible studies for missing or unpublished data. The evidence is current to 28 April 2015.
Selection criteria
Two review authors independently screened the relevant citations for randomised controlled trials (RCTs) comparing different GnRH agonist versus GnRH antagonist protocols in women undergoing in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI).
Data collection and analysis
Two review authors independently assessed trial eligibility and risk of bias, and extracted the data. The primary review outcomes were live birth and ovarian hyperstimulation syndrome (OHSS). Other adverse effects (miscarriage and cycle cancellation) were secondary outcomes. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I2 statistic. We assessed the overall quality of the evidence for each comparison using GRADE methods.
Main results
We included 73 RCTs, with 12,212 participants, comparing GnRH antagonist to long‐course GnRH agonist protocols. The quality of the evidence was moderate: limitations were poor reporting of study methods.
Live birth
There was no evidence of a difference in live birth rate between GnRH antagonist and long course GnRH agonist (OR 1.02, 95% CI 0.85 to 1.23; 12 RCTs, n = 2303, I2= 27%, moderate quality evidence). The evidence suggested that if the chance of live birth following GnRH agonist is assumed to be 29%, the chance following GnRH antagonist would be between 25% and 33%.
OHSS
GnRH antagonist was associated with lower incidence of any grade of OHSS than GnRH agonist (OR 0.61, 95% C 0.51 to 0.72; 36 RCTs, n = 7944, I2 = 31%, moderate quality evidence). The evidence suggested that if the risk of OHSS following GnRH agonist is assumed to be 11%, the risk following GnRH antagonist would be between 6% and 9%.
Other adverse effects
There was no evidence of a difference in miscarriage rate per woman randomised between GnRH antagonist group and GnRH agonist group (OR 1.03, 95% CI 0.82 to 1.29; 34 RCTs, n = 7082, I2 = 0%, moderate quality evidence).
With respect to cycle cancellation, GnRH antagonist was associated with a lower incidence of cycle cancellation due to high risk of OHSS (OR 0.47, 95% CI 0.32 to 0.69; 19 RCTs, n = 4256, I2 = 0%). However cycle cancellation due to poor ovarian response was higher in women who received GnRH antagonist than those who were treated with GnRH agonist (OR 1.32, 95% CI 1.06 to 1.65; 25 RCTs, n = 5230, I2 = 68%; moderate quality evidence).
Authors' conclusions
There is moderate quality evidence that the use of GnRH antagonist compared with long‐course GnRH agonist protocols is associated with a substantial reduction in OHSS without reducing the likelihood of achieving live birth.
This Committee Opinion provides practitioners with suggestions to reduce the likelihood of iatrogenic multiple gestation resulting from infertility treatment. This document replaces the document of ...the same name previously published in 2012 (Fertil Steril 2012;97:825-34 by the American Society for Reproductive Medicine).
Abstract
BACKGROUND
Polycystic ovary syndrome (PCOS) is the most frequent cause of anovulatory infertility. In women with PCOS, effective ovulation induction serves as an important first-line ...treatment for anovulatory infertility. Individual participant data (IPD) meta-analysis is considered as the gold standard for evidence synthesis which provides accurate assessments of outcomes from primary randomised controlled trials (RCTs) and allows additional analyses for time-to-event outcomes. It also facilitates treatment–covariate interaction analyses and therefore offers an opportunity for personalised medicine.
OBJECTIVE AND RATIONALE
We aimed to evaluate the effectiveness of different ovulation induction agents, in particular letrozole alone and clomiphene citrate (CC) plus metformin, as compared to CC alone, as the first-line choice for ovulation induction in women with PCOS and infertility, and to explore interactions between treatment and participant-level baseline characteristics.
SEARCH METHODS
We searched electronic databases including MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials up to 20 December 2018. We included RCTs comparing the following interventions with each other or placebo/no treatment in women with PCOS and infertility: CC, metformin, CC plus metformin, letrozole, gonadotrophin and tamoxifen. We excluded studies on treatment-resistant women. The primary outcome was live birth. We contacted the investigators of eligible RCTs to share the IPD and performed IPD meta-analyses. We assessed the risk of bias by using the Cochrane risk of bias tool for RCTs.
OUTCOMES
IPD of 20 RCTs including 3962 women with PCOS were obtained. Six RCTs compared letrozole and CC in 1284 women. Compared with CC, letrozole improved live birth rates (3 RCTs, 1043 women, risk ratio RR 1.43, 95% confidence interval CI 1.17–1.75, moderate-certainty evidence) and clinical pregnancy rates (6 RCTs, 1284 women, RR 1.45, 95% CI 1.23–1.70, moderate-certainty evidence) and reduced time-to-pregnancy (6 RCTs, 1235 women, hazard ratio HR 1.72, 95% CI 1.38–2.15, moderate-certainty evidence). Meta-analyses of effect modifications showed a positive interaction between baseline serum total testosterone levels and treatment effects on live birth (interaction RR 1.29, 95% CI 1.01–1.65). Eight RCTs compared CC plus metformin to CC alone in 1039 women. Compared with CC alone, CC plus metformin might improve clinical pregnancy rates (8 RCTs, 1039 women, RR 1.18, 95% CI 1.00–1.39, low-certainty evidence) and might reduce time-to-pregnancy (7 RCTs, 898 women, HR 1.25, 95% CI 1.00–1.57, low-certainty evidence), but there was insufficient evidence of a difference on live birth rates (5 RCTs, 907 women, RR 1.08, 95% CI 0.87–1.35, low-certainty evidence). Meta-analyses of effect modifications showed a positive interaction between baseline insulin levels and treatment effects on live birth in the comparison between CC plus metformin and CC (interaction RR 1.03, 95% CI 1.01–1.06).
WIDER IMPLICATIONS
In women with PCOS, letrozole improves live birth and clinical pregnancy rates and reduces time-to-pregnancy compared to CC and therefore can be recommended as the preferred first-line treatment for women with PCOS and infertility. CC plus metformin may increase clinical pregnancy and may reduce time-to-pregnancy compared to CC alone, while there is insufficient evidence of a difference on live birth. Treatment effects of letrozole are influenced by baseline serum levels of total testosterone, while those of CC plus metformin are affected by baseline serum levels of insulin. These interactions between treatments and biomarkers on hyperandrogenaemia and insulin resistance provide further insights into a personalised approach for the management of anovulatory infertility related to PCOS.
To evaluate the association between the number of oocytes retrieved and cumulative live birth rates.
Retrospective multicenter analysis using individual patient data.
Tertiary referral hospitals.
In ...total, 14,469 patients were analyzed. The study included the first cycle of patients stimulated for IVF/intracytoplasmic sperm injection (ICSI) from 2009 to 2014. All patients included in the analysis had either delivered a baby or had used all their embryos after their first stimulated cycle. All patients had vitrification as cryopreservation method. All women were followed up for at least 2 years.
Ovarian stimulation with GnRH antagonist protocol for IVF/ICSI.
The primary outcome was the cumulative live birth rate defined as the delivery of at least one live-born infant (>24 weeks of gestation) in the fresh or in the subsequent frozen-thawed cycles in relation to the number of oocytes retrieved. Only the first delivery was considered in the analysis. The secondary outcome was live birth after the fresh IVF/ICSI cycle only.
Cumulative live birth rates steadily increased with the number of oocytes, reaching 70% when ≥25 oocytes were retrieved. Interestingly, no plateau in cumulative live birth rates was observed, but a moderate increase of 5.1% on average was detected beyond 27 oocytes. Regarding the fresh cycle outcome, live birth probability increased up to seven oocytes retrieved and remained relatively unchanged (increase or decrease of ≤5%) between seven and 20 oocytes retrieved. However, a drop in fresh live birth rates was identified thereafter, which could be attributed to the progressive increase in "freeze-all" cycle rate with the number of oocytes retrieved, exceeding 20% in patients with >20 oocytes retrieved.
This is the largest multicenter study evaluating for the first time the impact of ovarian response on cumulative live birth rate. The significant progressive increase of cumulative live birth rate with the number of oocytes in our study suggests that ovarian stimulation may not have a detrimental effect on oocyte/embryo quality in good-prognosis women less than 40 year old. Nevertheless, although very high ovarian response may further increase cumulative live birth rates, ovarian stimulation should be rational and avoid extreme response in terms of oocytes retrieved to preserve patients' convenience and safety and avoid ovarian hyperstimulation syndrome or other iatrogenic complications.
Ovarian hyperstimulation syndrome (OHSS) is an uncommon but serious complication associated with assisted reproductive technology (ART). This systematic review aims to identify who is at high risk, ...how to prevent OHSS, and the treatment for existing OHSS.
Background
Polycystic ovary syndrome (PCOS) is the most common cause of infrequent periods (oligomenorrhoea) and absence of periods (amenorrhoea). It affects about 4% to 8% of women worldwide and ...often leads to anovulatory subfertility. Aromatase inhibitors (AIs) are a class of drugs that were introduced for ovulation induction in 2001. Since about 2001 clinical trials have reached differing conclusions as to whether the AI letrozole is at least as effective as the first‐line treatment clomiphene citrate (CC).
Objectives
To evaluate the effectiveness and safety of aromatase inhibitors for subfertile women with anovulatory PCOS for ovulation induction followed by timed intercourse or intrauterine insemination (IUI).
Search methods
We searched the following sources from inception to November 2017 to identify relevant randomised controlled trials (RCTs): the Cochrane Gynaecology and Fertility Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PsycINFO, Pubmed, LILACS, Web of Knowledge, the World Health Organization (WHO) clinical trials register and Clinicaltrials.gov. We also searched the references of relevant articles. We did not restrict the searches by language or publication status.
Selection criteria
We included all RCTs of AIs used alone or with other medical therapies for ovulation induction in women of reproductive age with anovulatory PCOS.
Data collection and analysis
Two review authors independently selected trials, extracted the data and assessed risks of bias. We pooled studies where appropriate using a fixed‐effect model to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for most outcomes, and risk differences (RDs) for ovarian hyperstimulation syndrome (OHSS). The primary outcomes were live birth and OHSS. Secondary outcomes were clinical pregnancy, miscarriage and multiple pregnancy. We assessed the quality of the evidence for each comparison using GRADE methods.
Main results
This is a substantive update of a previous review. We identified 16 additional studies for the 2018 update. We include 42 RCTs (7935 women). The aromatase inhibitor letrozole was used in all studies.
Letrozole compared to clomiphene citrate (CC) with or without adjuncts followed by timed intercourse
Live birth rates were higher with letrozole (with or without adjuncts) compared to clomiphene citrate (with our without adjuncts) followed by timed intercourse (OR 1.68, 95% CI 1.42 to 1.99; 2954 participants; 13 studies; I2 = 0%; number needed to treat for an additional beneficial outcome (NNTB) = 10; moderate‐quality evidence). There is high‐quality evidence that OHSS rates are similar with letrozole or clomiphene citrate (0.5% in both arms: risk difference (RD) −0.00, 95% CI −0.01 to 0.00; 2536 participants; 12 studies; I2 = 0%; high‐quality evidence). There is evidence for a higher pregnancy rate in favour of letrozole (OR 1.56, 95% CI 1.37 to 1.78; 4629 participants; 25 studies; I2 = 1%; NNTB = 10; moderate‐quality evidence). There is little or no difference between treatment groups in the rate of miscarriage by pregnancy (20% with CC versus 19% with letrozole; OR 0.94, 95% CI 0.70 to 1.26; 1210 participants; 18 studies; I2 = 0%; high‐quality evidence) and multiple pregnancy rate (1.7% with CC versus 1.3% with letrozole; OR 0.69, 95% CI 0.41 to 1.16; 3579 participants; 17 studies; I2 = 0%; high‐quality evidence). However, a funnel plot showed mild asymmetry, indicating that some studies in favour of clomiphene might be missing.
Letrozole compared to laparoscopic ovarian drilling
There is low‐quality evidence that live birth rates are similar with letrozole or laparoscopic ovarian drilling (OR 1.38, 95% CI 0.95 to 2.02; 548 participants; 3 studies; I2 = 23%; low‐quality evidence). There is insufficient evidence for a difference in OHSS rates (RD 0.00, 95% CI −0.01 to 0.01; 260 participants; 1 study; low‐quality evidence). There is low‐quality evidence that pregnancy rates are similar (OR 1.28, 95% CI 0.94 to 1.74; 774 participants; 5 studies; I2 = 0%; moderate‐quality evidence). There is insufficient evidence for a difference in miscarriage rate by pregnancy (OR 0.66, 95% CI 0.30 to 1.43; 240 participants; 5 studies; I2 = 0%; moderate‐quality evidence), or multiple pregnancies (OR 3.00, 95% CI 0.12 to 74.90; 548 participants; 3 studies; I2 = 0%; low‐quality evidence).
Additional comparisons were made for Letrozole versus placebo, Selective oestrogen receptor modulators (SERMS) followed by intrauterine insemination (IUI), follicle stimulating hormone (FSH), Anastrozole, as well as dosage and administration protocols.
There is insufficient evidence for a difference in either group of treatment due to a limited number of studies. Hence more research is necessary.
Authors' conclusions
Letrozole appears to improve live birth and pregnancy rates in subfertile women with anovulatory polycystic ovary syndrome, compared to clomiphene citrate. There is high‐quality evidence that OHSS rates are similar with letrozole or clomiphene citrate. There is high‐quality evidence of no difference in miscarriage rates or multiple pregnancy rates. There is low‐quality evidence of no difference in live birth and pregnancy rates between letrozole and laparoscopic ovarian drilling, although there were few relevant studies. For the 2018 update, we added good‐quality trials, upgrading the quality of the evidence.
With our increasing appreciation that simply maximizing oocyte yield for all patients is no longer an appropriate stimulation strategy and that age alone cannot accurately predict ovarian response, ...there has been an explosion in the literature regarding the utility of biomarkers to predict and individualize treatment strategies. Antral follicle count (AFC) and antimüllerian hormone (AMH) have begun to dominate the clinical scene, and although frequently pitted against each other as alternatives, both may contribute and indeed be synergistic. Their underlying technologies are continuing to develop rapidly and overcome the standardization issues that have limited their development to date. In the context of in vitro fertilization (IVF), their linear relationship with oocyte yield and thereby extremes of ovarian response has led to improved pretreatment patient counseling, individualization of stimulation strategies, increased cost effectiveness, and enhanced safety. This review highlights that although biomarkers of ovarian response started in the IVF clinic, their future extends well beyond the boundaries of assisted reproduction. The automation of AMH and its introduction into the routine repertoire of clinical biochemistry has tremendous potential. A future where primary care physicians, endocrinologists, and oncologists can rapidly assess ovarian dysfunction and the ovarian reserve more accurately than with the current standard of follicle-stimulating hormone (FSH) is an exciting possibility. For women, the ability to know the duration of their own reproductive life span will be empowering and allow them to redefine the meaning of family planning.
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