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Featured researches published by M. van Wely.


Human Reproduction Update | 2013

BMI in relation to sperm count: an updated systematic review and collaborative meta-analysis

N. Sermondade; C. Faure; L. Fezeu; A.G. Shayeb; Jens Peter Bonde; T.K. Jensen; M. van Wely; J. Cao; A.C. Martini; M. Eskandar; Jorge E. Chavarro; S. Koloszar; John M. Twigt; Cecilia Høst Ramlau-Hansen; E. Borges; Francesco Lotti; Régine P.M. Steegers-Theunissen; B. Zorn; A.J. Polotsky; S. La Vignera; Brenda Eskenazi; Kelton Tremellen; E.V. Magnusdottir; I. Fejes; Serge Hercberg; R. Lévy; Sébastien Czernichow

BACKGROUND The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to update the evidence on the association between BMI and sperm count through a systematic review with meta-analysis. METHODS A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n = 717 men) obtained from the Infertility Center of Bondy, France. Abstracts of relevant articles were examined and studies that could be included in this review were retrieved. Authors of relevant studies for the meta-analysis were contacted by email and asked to provide standardized data. RESULTS A total of 21 studies were included in the meta-analysis, resulting in a sample of 13 077 men from the general population and attending fertility clinics. Data were stratified according to the total sperm count as normozoospermia, oligozoospermia and azoospermia. Standardized weighted mean differences in sperm concentration did not differ significantly across BMI categories. There was a J-shaped relationship between BMI categories and risk of oligozoospermia or azoospermia. Compared with men of normal weight, the odds ratio (95% confidence interval) for oligozoospermia or azoospermia was 1.15 (0.93-1.43) for underweight, 1.11 (1.01-1.21) for overweight, 1.28 (1.06-1.55) for obese and 2.04 (1.59-2.62) for morbidly obese men. CONCLUSIONS Overweight and obesity were associated with an increased prevalence of azoospermia or oligozoospermia. The main limitation of this report is that studied populations varied, with men recruited from both the general population and infertile couples. Whether weight normalization could improve sperm parameters should be evaluated further.


Human Reproduction Update | 2010

Predictive factors in in vitro fertilization (IVF): a systematic review and meta-analysis

L.L. van Loendersloot; M. van Wely; J. Limpens; P.M.M. Bossuyt; S. Repping; F. van der Veen

BACKGROUND Various models have been developed for the prediction of pregnancy after in vitro fertilization (IVF). These models differ from one another in the predictors they include. We performed a systematic review and meta-analysis to identify the most relevant predictors for success in IVF. METHODS We systematically searched MEDLINE and EMBASE for studies evaluating IVF/ICSI outcome. Studies were included if they reported an unconditional odds ratio (OR) or whenever one could be calculated for one or more of the following factors: age, type of infertility, indication, duration of infertility, basal FSH, number of oocytes, fertilization method, number of embryos transferred and embryo quality. RESULTS Fourteen studies were identified. A summary OR could be calculated for five factors. We found negative associations between pregnancy and female age [OR: 0.95, 95% confidence interval (CI): 0.94-0.96], duration of subfertility (OR: 0.99, 95% CI: 0.98-1.00) and basal FSH (OR: 0.94, 95% CI: 0.88-1.00). We found a positive association with number of oocytes (OR 1.04, 95% CI: 1.02-1.07). Better embryo quality was associated with higher pregnancy chances. No significant association was found for the type of infertility and fertilization method. A summary OR for IVF indication and number of embryos transferred could not be calculated, because studies reporting on these used different reference categories. CONCLUSIONS Female age, duration of subfertility, bFSH and number of oocytes, all reflecting ovarian function, are predictors of pregnancy after IVF. Better quality studies are necessary, especially studies that focus on embryo factors that are predictive of success in IVF.


Human Reproduction Update | 2008

The influence of the number of follicles on pregnancy rates in intrauterine insemination with ovarian stimulation: a meta-analysis

M.M.E. van Rumste; Inge M. Custers; F. van der Veen; M. van Wely; J.L.H. Evers; B.W. Mol

BACKGROUND The influence of multifollicular growth on pregnancy rates in subfertile couples undergoing intrauterine insemination (IUI) with controlled ovarian hyperstimulation (COH) remained unclear. METHODS Relevant papers were identified by searching MEDLINE, EMBASE and the Cochrane Library. A meta-analysis was performed and Mantel-Haenszel pooled odd ratios (ORs) and risk differences with 99% confidence intervals (CIs) were calculated to express the relation between the number of follicles and pregnancy rates. RESULTS We included 14 studies reporting on 11 599 cycles. The absolute pregnancy rate was 8.4% for monofollicular and 15% for multifollicular growth. The pooled OR for pregnancy after two follicles as compared with monofollicular growth was 1.6 (99% CI 1.3-2.0), whereas for three and four follicles, this was 2.0 and 2.0, respectively. Compared with monofollicular growth, pregnancy rates increased by 5, 8 and 8% when stimulating two, three and four follicles. The pooled OR for multiple pregnancies after two follicles was 1.7 (99% CI 0.8-3.6), whereas for three and four follicles this was 2.8 and 2.3, respectively. The risk of multiple pregnancies after two, three and four follicles increased by 6, 14 and 10%. The absolute rate of multiple pregnancies was 0.3% after monofollicular and 2.8% after multifollicular growth. CONCLUSIONS Multifollicular growth is associated with increased pregnancy rates in IUI with COH. Since in cycles with three or four follicles the multiple pregnancy rate increased without substantial gain in overall pregnancy rate, IUI with COH should not aim for more than two follicles. One stimulated follicle should be the goal if safety is the primary concern, whereas two follicles may be accepted after careful patient counselling.


Human Reproduction Update | 2012

Treatment of thyroid disorders before conception and in early pregnancy: a systematic review

Rosa Vissenberg; E. van den Boogaard; M. van Wely; J.A. van der Post; Eric Fliers; Peter H. Bisschop; M. Goddijn

BACKGROUND Thyroid disorders are associated with pregnancy complications. Universal screening is currently not recommended because of a lack of evidence on the effectiveness of treatment. Women with hyperthyroidism and hypothyroidism evidently require treatment but this is less clear for women with subclinical hypothyroidism and thyroid autoimmunity. Therefore, we conducted a systematic review to provide a comprehensive overview on the available treatment interventions. METHODS Relevant studies were identified by searching Medline, EMBASE and Cochrane Controlled Trials Register, published until December 2011. RESULTS From a total of 7334 primary selected titles, 22 articles were included for the systematic review and 11 were appropriate for meta-analyses. Eight studies reported on hyperthyroidism. Propylthiouracil (PTU) and methimazole reduce the risk for preterm delivery [risk ratio (RR): 0.23, confidence interval (CI): 0.1-0.52], pre-eclampsia (RR: 0.23, CI: 0.06-0.89) and low birthweight (RR: 0.38, CI: 0.22-0.66). The nine studies that reported on clinical hypothyroidism showed that levothyroxine is effective in reducing the risk for miscarriage (RR: 0.19, CI: 0.08-0.39) and preterm delivery (RR: 0.41, CI: 0.24-0.68). For treatment of subclinical hypothyroidism, current evidence is insufficient. The five studies available on thyroid autoimmunity showed a not significant reduction in miscarriage (RR: 0.58, CI: 0.32-1.06), but significant reduction in preterm birth by treatment with levothyoxine (RR: 0.31, CI: 0.11-0.90). CONCLUSION For hyperthyroidism, methimazole and PTU are effective in preventing pregnancy complications. For clinical hypothyroidism, treatment with levothyroxine is recommended. For subclinical hypothyroidism and thyroid autoimmunity, evidence is insufficient to recommend treatment with levothyroxine. The overall lack of evidence precludes a recommendation for universal screening and is only justified in a research setting.


Human Reproduction Update | 2013

Embryo culture media and IVF/ICSI success rates: a systematic review

Eleni Mantikou; M.A.F.M. Youssef; M. van Wely; F. van der Veen; Hesham Al-Inany; Sjoerd Repping; Sebastiaan Mastenbroek

BACKGROUND The media that are used to culture human preimplantation embryos are considered to be an important factor for the success rates of IVF/ICSI. Here, we present a systematic review of randomized controlled trials (RCTs) on the effect of culture media on IVF/ICSI success rates. METHODS RCTs published between January 1985 and July 2012 were eligible for inclusion. The primary outcome was live birth. Secondary outcomes were health of babies born, ongoing pregnancies, clinical pregnancies, miscarriages, multiple pregnancies, implantation rate, cryopreservation rate, embryo quality and fertilization rate. For those media that were evaluated in more than one comparison, an unconventional meta-analysis was performed by pooling the data of the media they were compared to. RESULTS Twenty-two RCTs were included that evaluated 31 different comparisons. Conventional meta-analysis was not possible for any of the outcomes as nearly all trials compared different culture media. Only four trials reported on live birth, and one of them reported a significant difference. Nine trials reported on ongoing and/or clinical pregnancy rates, of which four showed a significant difference. Pooling the data did not reveal a superior culture medium. CONCLUSIONS It is yet unknown what culture medium leads to the best success rates in IVF/ICSI. Given the potential importance of culture media for treatment outcome, rigorously designed RCTs are needed for currently available, as well as newly introduced culture media.


Human Reproduction | 2013

Methotrexate or expectant management in women with an ectopic pregnancy or pregnancy of unknown location and low serum hCG concentrations? A randomized comparison

N.M. van Mello; Femke Mol; Harold R. Verhoeve; M. van Wely; Albert H. Adriaanse; Erik A. Boss; Antonius B Dijkman; N. Bayram; Mark Hans Emanuel; Jaap Friederich; L. van der Leeuw-Harmsen; J.P. Lips; M.A. van Kessel; Willem M. Ankum; F. van der Veen; Bwj Mol; Petra J. Hajenius

STUDY QUESTION What is the treatment success rate of systemic methotrexate (MTX) compared with expectant management in women with an ectopic pregnancy or a pregnancy of unknown location (PUL) with low and plateauing serum hCG concentrations? SUMMARY ANSWER In women with an ectopic pregnancy or a PUL and low and plateauing serum hCG concentrations, expectant management is an alternative to medical treatment with single-dose systemic MTX. WHAT IS KNOWN AND WHAT THIS PAPER ADDS MTX is often used in asymptomatic women with an ectopic pregnancy or a PUL with low and plateauing serum hCG concentrations. These pregnancies may be self-limiting and watchful waiting is suggested as an alternative, but evidence from RCTs is lacking. The results of this RCT show that expectant management is an alternative to treatment with systemic MTX in a single-dose regimen in these women. STUDY DESIGN, SIZE, DURATION A multicentre RCT women were assigned to systemic MTX (single dose) treatment or expectant management, using a web-based randomization program, block randomization with stratification for hospital and serum hCG concentration (<1000 versus 1000-2000 IU/l). The primary outcome measure was an uneventful decline of serum hCG to an undetectable level (<2 IU/l) by the initial intervention strategy. Secondary outcome measures included additional treatment, side effects and serum hCG clearance time. PARTICIPANTS, SETTING, METHODS From April 2007 to January 2012, we performed a multicentre study in The Netherlands. All haemodynamically stable women >18 years old with both an ectopic pregnancy visible on transvaginal sonography and a plateauing serum hCG concentration <1500 IU/l or with a PUL and a plateauing serum hCG concentration <2000 IU/l were eligible for the trial. MAIN RESULTS We included 73 women of whom 41 were allocated to single-dose MTX and 32 to expectant management. There was no difference in primary treatment success rate of single-dose MTX versus expectant management, 31/41 (76%) and 19/32 (59%), respectively [relative risk (RR) 1.3 95% confidence interval (CI) 0.9-1.8]. In nine women (22%), additional MTX injections were needed, compared with nine women (28%) in whom systemic MTX was administered after initial expectant management (RR 0.8; 95% CI 0.4-1.7). One woman (2%) from the MTX group underwent surgery compared with four women (13%) in the expectant management group (RR 0.2; 95% CI 0.02-1.7), all after experiencing abdominal pain within the first week of follow-up. In the MTX group, nine women reported side effects versus none in the expectant management group. No serious adverse events were reported. Single-dose systemic MTX does not have a larger treatment effect compared with expectant management in women with an ectopic pregnancy or a PUL and low and plateauing serum hCG concentrations. WIDER IMPLICATIONS OF THE FINDINGS Sixty percent of women after expectant management had an uneventful clinical course with steadily declining serum hCG levels without any intervention, which means that MTX, a potentially harmful drug, can be withheld in these women. BIAS, LIMITATION AND GENERALISABILITY: A limitation of this RCT is that it was an open (not placebo controlled) trial. Nevertheless, introduction of bias was probably limited by the strict criteria to be fulfilled for treatment with MTX. STUDY FUNDING This trial is supported by a grant of the Netherlands Organization for Health Research and Development (ZonMw Clinical fellow grant 90700154). TRIAL REGISTRATION ISRCTN 48210491.


BMJ | 2015

Prevention of multiple pregnancies in couples with unexplained or mild male subfertility: randomised controlled trial of in vitro fertilisation with single embryo transfer or in vitro fertilisation in modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation

A.J. Bensdorp; R. I. Tjon-Kon-Fat; P. M. M. Bossuyt; C.A.M. Koks; G.J.E. Oosterhuis; Annemieke Hoek; Peter G.A. Hompes; F. J. Broekmans; Harold R. Verhoeve; J.P. de Bruin; R. van Golde; Sjoerd Repping; B.J. Cohlen; M. D. A. Lambers; van Peter Bommel; Denise A. M. Perquin; J.M.J. Smeenk; M. J. Pelinck; Judith Gianotten; Diederik A. Hoozemans; J. W. M. Maas; M.J. Eijkemans; F. van der Veen; B.W. Mol; M. van Wely

Objectives To compare the effectiveness of in vitro fertilisation with single embryo transfer or in vitro fertilisation in a modified natural cycle with that of intrauterine insemination with controlled ovarian hyperstimulation in terms of a healthy child. Design Multicentre, open label, three arm, parallel group, randomised controlled non-inferiority trial. Setting 17 centres in the Netherlands. Participants Couples seeking fertility treatment after at least 12 months of unprotected intercourse, with the female partner aged between 18 and 38 years, an unfavourable prognosis for natural conception, and a diagnosis of unexplained or mild male subfertility. Interventions Three cycles of in vitro fertilisation with single embryo transfer (plus subsequent cryocycles), six cycles of in vitro fertilisation in a modified natural cycle, or six cycles of intrauterine insemination with ovarian hyperstimulation within 12 months after randomisation. Main outcome measures The primary outcome was birth of a healthy child resulting from a singleton pregnancy conceived within 12 months after randomisation. Secondary outcomes were live birth, clinical pregnancy, ongoing pregnancy, multiple pregnancy, time to pregnancy, complications of pregnancy, and neonatal morbidity and mortality Results 602 couples were randomly assigned between January 2009 and February 2012; 201 were allocated to in vitro fertilisation with single embryo transfer, 194 to in vitro fertilisation in a modified natural cycle, and 207 to intrauterine insemination with controlled ovarian hyperstimulation. Birth of a healthy child occurred in 104 (52%) couples in the in vitro fertilisation with single embryo transfer group, 83 (43%) in the in vitro fertilisation in a modified natural cycle group, and 97 (47%) in the intrauterine insemination with controlled ovarian hyperstimulation group. This corresponds to a risk, relative to intrauterine insemination with ovarian hyperstimulation, of 1.10 (95% confidence interval 0.91 to 1.34) for in vitro fertilisation with single embryo transfer and 0.91 (0.73 to 1.14) for in vitro fertilisation in a modified natural cycle. These 95% confidence intervals do not extend below the predefined threshold of 0.69 for inferiority. Multiple pregnancy rates per ongoing pregnancy were 6% (7/121) after in vitro fertilisation with single embryo transfer, 5% (5/102) after in vitro fertilisation in a modified natural cycle, and 7% (8/119) after intrauterine insemination with ovarian hyperstimulation (one sided P=0.52 for in vitro fertilisation with single embryo transfer compared with intrauterine insemination with ovarian hyperstimulation; one sided P=0.33 for in vitro fertilisation in a modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation). Conclusions In vitro fertilisation with single embryo transfer and in vitro fertilisation in a modified natural cycle were non-inferior to intrauterine insemination with controlled ovarian hyperstimulation in terms of the birth of a healthy child and showed comparable, low multiple pregnancy rates. Trial registration Current Controlled Trials ISRCTN52843371; Nederlands Trial Register NTR939.


Gynecological Endocrinology | 2011

Can metformin reduce the incidence of gestational diabetes mellitus in pregnant women with polycystic ovary syndrome? Prospective cohort study

Sherif Khattab; Iman Abdel Mohsen; I. Aboul Foutouh; H. S. Ashmawi; M. N. Mohsen; M. van Wely; F. van der Veen; M. Af. Youssef

Background. Women with polycystic ovary syndrome (PCOS) are at a high risk to develop Gestational Diabetes mellitus (GDM). We hypothesized that metformin due to its metabolic, endocrine, vascular, and anti-inflammatory effects may reduce the incidence of GDM in PCOS women. Patient and method. We carried out a prospective cohort study to determine the beneficial effects of metformin on PCOS patients during pregnancy. Three-hundred and sixty non-diabetic PCOS patients were included who were conceived on metformin by different treatment modalities. Two-hundred pregnant women continued on metformin at a dose of 1000–2000 mg daily throughout pregnancy (study group) and 160 women discontinued metformin use at the time of conception (control group). Results. There is a statistically significant reduction in the incidence of GDM in favor of metformin group (OR: 0.17, 95% CI: 0.07–0.37). There is a statistically significant reduction in the incidence of pre-eclampsia in favor of metformin group (OR: 0.35, 95% CI: 0.13–0.94). Conclusion. Metformin is a promising medication for the prevention or reduction of the incidence of GDM and pre-eclampsia in PCOS women.


Human Reproduction | 2011

Long-term outcomes in women with polycystic ovary syndrome initially randomized to receive laparoscopic electrocautery of the ovaries or ovulation induction with gonadotrophins

Marleen J. Nahuis; N. Kose; N. Bayram; H.J.H.M. van Dessel; D.D.M. Braat; C.J.C.M. Hamilton; Peter G.A. Hompes; P. M. M. Bossuyt; Bwj Mol; F. van der Veen; M. van Wely

BACKGROUND Long-term effects of laparoscopic electrocautery of the ovaries are unknown. To study the long-term effects of laparoscopic electrocautery of the ovaries and gonadotrophins, we followed women with clomiphene-resistant polycystic ovary syndrome (PCOS) randomly allocated to one of these treatments until 8-12 years after their initial treatment. METHODS Between February 1998 and October 2001 168 women with clomiphene citrate-resistant PCOS were included in a randomized controlled trial comparing an electrocautery strategy to a strategy starting with rFSH. In 2009 these women were contacted about their reproductive outcome and menstrual cycle regularity. Analysis was by intention-to-treat. We compared time to conception resulting in live birth, subsequent pregnancies, ectopic and multiple pregnancies, menopause, as well as minimal and maximal menstrual cycle length. RESULTS After 8-12 years, the cumulative proportion of women with a first child was 86% in women who had been allocated to electrocautery versus 81% in women who had been allocated to immediate rFSH [relative ratio (RR): 1.1; 95% confidence interval (CI): 0.92-1.2]. Treatment with electrocautery resulted in a significantly lower need for stimulated cycles to reach a live birth; 53% after electrocautery versus 76% after rFSH (RR: 0.69; 95% CI: 0.55-0.88).The cumulative proportion of women with a second child was 61% after electrocautery versus 46% after immediate rFSH (RR: 1.4; 95% CI: 1.00-1.9). Overall, there were 7 twins out of 134 deliveries (5%) after electrocautery versus 10 twins out of 124 deliveries (8%) in the rFSH group (RR: 0.65; 95% CI: 0.25-1.6). Fifty-four per cent of the women allocated to electrocautery had a regular menstrual cycle 8-12 years after randomization versus 36% in those allocated to rFSH (RR: 1.5; 95% CI: 0.87-2.6). CONCLUSION In women with clomiphene-resistant PCOS, laparoscopic electrocautery of the ovaries is as effective as ovulation induction with FSH treatment in terms of live births, but reduces the need for ovulation induction or ART in a significantly higher proportion of women and increases the chance for a second child. Clinicians may use these data when informing clomiphene-resistant anovulatory women about treatment options.


Journal of Advanced Research | 2014

Prediction models in in vitro fertilization; where are we? A mini review

Laura van Loendersloot; Sjoerd Repping; P. M. M. Bossuyt; F. van der Veen; M. van Wely

Since the introduction of in vitro fertilization (IVF) in 1978, over five million babies have been born worldwide using IVF. Contrary to the perception of many, IVF does not guarantee success. Almost 50% of couples that start IVF will remain childless, even if they undergo multiple IVF cycles. The decision to start or pursue with IVF is challenging due to the high cost, the burden of the treatment, and the uncertain outcome. In optimal counseling on chances of a pregnancy with IVF, prediction models may play a role, since doctors are not able to correctly predict pregnancy chances. There are three phases of prediction model development: model derivation, model validation, and impact analysis. This review provides an overview on predictive factors in IVF, the available prediction models in IVF and provides key principles that can be used to critically appraise the literature on prediction models in IVF. We will address these points by the three phases of model development.

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B.W. Mol

University of Adelaide

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M.H. Mochtar

University of Amsterdam

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C.B. Lambalk

VU University Medical Center

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N. Bayram

University of Amsterdam

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