Research Topics
Species | C B LambalkSummaryAffiliation: University Hospital Vrije Universiteit Country: The Netherlands Publications
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Publications
Hypothetical risks of twinning in the natural menstrual cycleC B Lambalk
Division of Reproductive Endocrinology, Vrije Universiteit, Amsterdam, The Netherlands
Eur J Obstet Gynecol Reprod Biol 75:1-4. 1997..However, prospective experiments will be needed to prove the relation between this type of DZ twinning and possible patterns of serum FSH that mimic puberty under these circumstances...- Increased levels and pulsatility of follicle-stimulating hormone in mothers of hereditary dizygotic twinsC B Lambalk
Division of Reproductive Endocrinology, Free University, Amsterdam, The Netherlands
J Clin Endocrinol Metab 83:481-6. 1998..This is the result of altered responsiveness to ovarian feedback and/or pituitary or suprapituitary, non-LHRH-like mechanisms that stimulate pulsatile FSH... - Interpretation of elevated FSH in the regular menstrual cycleC B Lambalk
Department of Obstetrics and Gynaecology, Vrije Universiteit, Amsterdam, The Netherlands
Maturitas 30:215-20. 1998.... - The endocrinology of dizygotic twinning in the humanC B Lambalk
Research Institute of Endocrinology, Reproduction and Metabolism, Department of Obstetrics and Gynaecology, Medical Centre, Vrije Universiteit, Amsterdam, The Netherlands
Mol Cell Endocrinol 145:97-102. 1998.... - Genetic risk factors in tumours of the testis: lessons from twin studiesC B Lambalk
Research Institute for Endocrinology, Reproduction and Metabolism, Department of Obstetrics Gynaecology, Academic Hospital, Free University, Amsterdam, The Netherlands
Twin Res 1:154-5. 1998..We suggest to study FSH secretion in males of familial dizygotic twins and furthermore the risk of developing testicular carcinoma in males with elevated FSH. These men with one testicle and/or with dysfunctioning Sertoli/Leydig cells... - Natural versus induced twinning and pregnancy outcome: a Dutch nationwide survey of primiparous dizygotic twin deliveriesC B Lambalk
Research Institute of Endocrinology, Reproduction and Metabolism, Department of Obstetrics and Gynaecology, Medical Centre Vrije Universiteit, Amsterdam, The Netherlands
Fertil Steril 75:731-6. 2001..To compare obstetrical outcome of twin pregnancies after assisted reproduction with that of natural twin pregnancies... - A reduced size of the ovarian follicle pool is associated with an increased risk of a trisomic pregnancy in IVF-treated womenM L Haadsma
Department of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, PO Box 30 001, 9700 RB Groningen, The Netherlands
Hum Reprod 25:552-8. 2010..It has been hypothesized that the increase in meiotic errors is related to the decreasing number of oocytes with age. Our aim was to assess the relation between trisomic pregnancy and three parameters of oocyte quantity... - Factors determining early pregnancy loss in singleton and multiple implantationsM J Lambers
Department of Obstetrics, Gynecology and Reproductive Medicine, Vrije University Medical Center, Amsterdam, The Netherlands
Hum Reprod 22:275-9. 2007..The incidence of first trimester pregnancy loss is much lower in IVF twin pregnancies than in IVF singleton pregnancies. The objective of this study was to determine which embryonic and maternal factors contribute to this finding... - Further considerations on natural or mild hyperstimulation cycles for intrauterine insemination treatment: effects on pregnancy and multiple pregnancy ratesA J Goverde
Vrije Universiteit Medical Centre, Department of Reproductive Medicine, Division of Obstetrics and Gynaecology, Amsterdam, The Netherlands
Hum Reprod 20:3141-6. 2005.... - The paradox of declining fertility but increasing twinning rates with advancing maternal ageS N Beemsterboer
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije University Medical Centre, Amsterdam, The Netherlands
Hum Reprod 21:1531-2. 2006..In the presence of two good-quality oocytes, a twin pregnancy may result... - Clomiphene citrate resistance in relation to follicle-stimulating hormone receptor Ser680Ser-polymorphism in polycystic ovary syndromeA Overbeek
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
Hum Reprod 24:2007-13. 2009..The objective of this study was to evaluate the role of the follicle-stimulating hormone receptor (FSHR) Ser680Ser-polymorphism as a predictor for CC response... - Are GnRH antagonists comparable to agonists for use in IVF?J A Huirne
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, 1007 MB, Amsterdam, The Netherlands
Hum Reprod 22:2805-13. 2007..More studies comparing long GnRH agonist protocols with 'long' GnRH antagonist protocols, with enough power to identify differences in pregnancy rates, are required before appropriate comparison can be made... - Intercycle variability of ovarian reserve tests: results of a prospective randomized studyJ Kwee
Division of Reproductive Endocrinology and Fertility and the IVF Centre, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, PO Box 7057, 1007 MB Amsterdam, The Netherlands
Hum Reprod 19:590-5. 2004.... - Are elevated FSH concentrations in the pre-conceptional period a risk factor for Down's syndrome pregnancies?J M van Montfrans
Research Institute for Endocrinology, Reproduction and Metabolism, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands
Hum Reprod 16:1270-3. 2001..However, when elevated basal FSH concentrations are diagnosed during subfertility evaluation, an elevated risk for a Down's syndrome pregnancy could be discussed with women who become pregnant... - Gonadotrophin-releasing hormone agonist dose-dependency of pituitary desensitization during controlled ovarian hyperstimulation in IVFR M Janssens
Institute for Endocrinology, Reproduction and Metabolism, IVF Center, Free University Hospital, Amsterdam, The Netherlands
Hum Reprod 13:2386-91. 1998..Thus, a daily s.c. dose of 100 microg triptorelin acetate appears to be too high, since adequate desensitization of the pituitary (i.e. no spontaneous LH surge) can be achieved with doses as low as 15 and 50 microg... - The endocrine and follicular growth dynamics throughout the menstrual cycle in women with consistently or variably elevated early follicular phase FSH compared with controlsC H de Koning
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, PO Box 7057, 1007 MB Amsterdam, The Netherlands
Hum Reprod 23:1416-23. 2008.... - Elevated FSH concentrations in imminent ovarian failure are associated with higher FSH and LH pulse amplitude and response to GnRHC H de Koning
Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, PO Box 7057, 1007 MB Amsterdam, The Netherlands
Hum Reprod 15:1452-6. 2000..We concluded that in women with IOF, the pituitary is more sensitive to GnRH. This leads to higher FSH and LH pulse amplitudes which underlie the elevated FSH concentrations in the early follicular phase... - Ovarian response to standard gonadotrophin stimulation for IVF is decreased not only in older but also in younger women in couples with idiopathic and male subfertilityA J Goverde
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands
Hum Reprod 20:1573-7. 2005.... - Basal FSH concentrations as a marker of ovarian ageing are not related to pregnancy outcome in a general population of women over 30 yearsJ M van Montfrans
Research Institute for Endocrinology, Reproduction and Metabolism, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands
Hum Reprod 19:430-4. 2004..Since the majority of aneuploid conceptions end in early pregnancy loss or abortion of a recognized pregnancy, these determinants are appropriate intermediate end-points to study aneuploidy... - Pituitary sensitizing effect of GnRH antagonists: a mechanism explaining LH escape during IVF?F R Banga
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Centre VUmc, PO Box 7075, 1007 MB Amsterdam, The Netherlands
Hum Reprod 25:1513-9. 2010..We hypothesize that, under chronic GnRH antagonist administration, a higher pituitary response to GnRH could be an underlying mechanism explaining the escape phenomenon... - Frequency distribution of polymorphisms in the FSH receptor gene in infertility patients of different ethnicityE A M Kuijper
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, Amsterdam, The Netherlands
Reprod Biomed Online 20:588-93. 2010..This indicates that, when comparing allelic frequency distributions of the FSHR polymorphism variants, ethnic background should be accounted for. FSH concentrations did not differ between FSHR polymorphisms or between ethnic groups... - Frequency distribution of polymorphisms in the FSH receptor gene in infertility patients of different ethnicityE A M Kuijper
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, Amsterdam, The Netherlands
Reprod Biomed Online 22:S60-5. 2011..This indicates that, when comparing allelic frequency distributions of the FSHR polymorphism variants, ethnic background should be accounted for. FSH concentrations did not differ between FSHR polymorphisms or between ethnic groups... - Insulin-induced capillary recruitment is impaired in both lean and obese women with PCOSI J G Ketel
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, De Boelelaan 1118, Room OZ116 1, 1007 MB Amsterdam, The Netherlands
Hum Reprod 26:3130-7. 2011..Insulin-induced capillary recruitment (IICR) is considered a significant determinant of IMGU. We investigated whether IICR is a determinant IMGU in obese and lean women with and without PCOS... - Metabolomic profiling by near-infrared spectroscopy as a tool to assess embryo viability: a novel, non-invasive method for embryo selectionC G Vergouw
Department of Obstetrics, Gynaecology and Reproductive Medicine, VU University Medical Center, Amsterdam, The Netherlands
Hum Reprod 23:1499-504. 2008..In this study, we investigated if metabolomic profiling of biomarkers of embryo culture medium by near-infrared (NIR) spectroscopy has a correlation with ongoing pregnancy in SET... - Cetrorelix in an oral contraceptive-pretreated stimulation cycle compared with buserelin in IVF/ICSI patients treated with r-hFSH: a randomized, multicentre, phase IIIb studyJ A Huirne
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands
Hum Reprod 21:1408-15. 2006..Both regimens were well tolerated and allowed scheduling of the oocyte retrieval, with only small number of retrievals falling on a weekend or public holiday... - Heritability of reproductive hormones in adult male twinsE A M Kuijper
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, 1007 MB Amsterdam, The Netherlands
Hum Reprod 22:2153-9. 2007.... - The distribution of FSH receptor isoforms is related to basal FSH levels in subfertile women with normal menstrual cyclesC H de Koning
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, P.O.Box 7057, 1007 MB Amsterdam, The Netherlands
Hum Reprod 21:443-6. 2006..5%). CONCLUSIONS: The N680S sequence variation of the FSH receptor is found in >75% of the cases with elevated basal FSH and suggests a higher FSH threshold... - LH as a diagnostic criterion for polycystic ovary syndrome in patients with WHO II oligo/amenorrhoeaM L Hendriks
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
Reprod Biomed Online 16:765-71. 2008.... - Heritability of polycystic ovary syndrome in a Dutch twin-family studyJ M Vink
Department of Biological Psychology, Vrije Universiteit, Van de Boechorststraat 1, 1081 BT Amsterdam, The Netherlands
J Clin Endocrinol Metab 91:2100-4. 2006..Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders among women of reproductive age. There is evidence for a genetic component in PCOS based on familial clustering of cases... - Why does ovarian surgery in PCOS help? Insight into the endocrine implications of ovarian surgery for ovulation induction in polycystic ovary syndromeM L Hendriks
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, Amsterdam, The Netherlands
Hum Reprod Update 13:249-64. 2007..Additionally, anti-Müllerian hormone and gonadotrophin surge attenuating factor probably have a role in the endocrine changes... - Birth weight and age at menarche in patients with polycystic ovary syndrome or diminished ovarian reserve, in a retrospective cohortS Sadrzadeh
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU Medical Centre, Amsterdam, The Netherlands
Hum Reprod 18:2225-30. 2003..In most patients this was concomitant with elevated serum LH levels. Diminished ovarian reserve was defined as receiving a donated oocyte or having a low response to ovarian hyperstimulation... - Treatment with the GnRH antagonist ganirelix prevents premature LH rises and luteinization in stimulated intrauterine insemination: results of a double-blind, placebo-controlled, multicentre trialC B Lambalk
Department of Reproductive Medicine, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands, and Civic Parkdale Clinic, Ottawa, Ontario, Canada
Hum Reprod 21:632-9. 2006..This study was designed to assess whether the use of ganirelix in women undergoing stimulated IUI could prevent the occurrence of premature LH rises and luteinization (LH+progesterone rises)... - Assessment of ovarian reserve. Ovarian biopsy is not a valid method for the prediction of ovarian reserveC B Lambalk
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU Medical Centre, Amsterdam, The Netherlands
Hum Reprod 19:1055-9. 2004..We concluded that due to the huge variation in the distribution of follicles across the surface of the ovary, there is no place for this procedure in clinical evaluation of reproductive ageing in the individual patient... - Potential bias regarding birth weight in historical and contemporary twin data basesS Sadrzadeh
Department of Obstetrics and Gynaecology, VU Medical Centre, The Netherlands
Twin Res 4:332-6. 2001..We suggest that investigators using historical databases to test the fetal origins hypothesis should be aware of this increased likelihood of selective exclusion of individuals with extreme morphometric parameters at time of birth... - Gonadotropin-releasing-hormone-receptor antagonistsJ A Huirne
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, PO Box 7057, 1007MB, Amsterdam, Netherlands
Lancet 358:1793-803. 2001..However, the best clinical evidence so far has been in assisted reproduction and prostate cancer... - Greater arterial stiffness in polycystic ovary syndrome (PCOS) is an obesity--but not a PCOS-associated phenomenonI J Ketel
Division of Reproductive Medicine, Department of Obstetrics and Gynecology, Vrije Universiteit Medical Centre VU, Amsterdam, The Netherlands
J Clin Endocrinol Metab 95:4566-75. 2010..Polycystic ovary syndrome (PCOS) and obesity are associated with cardiovascular disease, but it is unclear to what extent they contribute independently. Arterial stiffness might link obesity and PCOS to cardiovascular diseases... - Comparison of endocrine tests with respect to their predictive value on the outcome of ovarian hyperstimulation in IVF treatment: results of a prospective randomized studyJ Kwee
Research Institute for Endocrinology, Reproduction and Metabolism, Department of Obstetrics and Gynaecology, Division of Reproductive Endocrinology and Fertility, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands
Hum Reprod 18:1422-7. 2003.... - Testing ovarian reserve to predict age at menopauseC B Lambalk
Division of Reproductive Medicine, Department of Obstetrics Gynaecology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands
Maturitas 63:280-91. 2009..Results of new and ongoing longitudinal studies may provide better predictive models. In particular, use of genetic profiles may add to the accuracy of currently known markers... - Purification of a candidate gonadotrophin surge-inhibiting/attenuating factor (GnSIF/AF) showing MAPK as a possible targetM L Hendriks
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, VU University Medical Center, Amsterdam, The Netherlands
Mol Reprod Dev 78:292-304. 2011..The results provide strong evidence that the identified candidate proteins are the true GnSIF/AF... - Basal FSH, estradiol and inhibin B concentrations in women with a previous Down's syndrome affected pregnancyJ M van Montfrans
Research Institute for Endocrinology, Reproduction and Metabolism, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Centre, Amsterdam, The Netherlands
Hum Reprod 17:44-7. 2002..However, it is not known whether these elevated basal FSH concentrations reflect depletion of the primordial follicle pool, or were caused by an increased secretory drive for FSH... - Ultrasonographically measured testicular volumes in 0- to 6-year-old boysE A M Kuijper
Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Vrije Universiteit Medical Center, 1007 MB Amsterdam, The Netherlands
Hum Reprod 23:792-6. 2008..Therefore, the aim of this study was to obtain ultrasonographically measured normative data for testicular volumes in 0- to 6-year-old boys... - Clomifene citrate or low-dose FSH for the first-line treatment of infertile women with anovulation associated with polycystic ovary syndrome: a prospective randomized multinational studyR Homburg
Reproductive Medicine, VU University Medical Center, Amsterdam, The Netherlands
Hum Reprod 27:468-73. 2012..Low-dose FSH has been reserved for women failing to conceive with CC. In this RCT, we tested the hypothesis that pregnancy rate (PR) and live birth rates (LBR) are higher after OI with low-dose FSH than with CC as first-line treatment...