Frans M Helmerhorst

Summary

Affiliation: Leiden University Medical Center
Country: The Netherlands

Publications

  1. pmc The OPTIMIST study: optimisation of cost effectiveness through individualised FSH stimulation dosages for IVF treatment. A randomised controlled trial
    Theodora C van Tilborg
    Department of Reproductive Medicine and Gynaecology, University Medical Centre Utrecht, University of Utrecht, Utrecht, The Netherlands
    BMC Womens Health 12:29. 2012
  2. pmc Perinatal outcome of singletons and twins after assisted conception: a systematic review of controlled studies
    Frans M Helmerhorst
    Department of Obstetrics, Gynaecology and Reproductive Medicine, Leiden University Medical Center, NL 2300 Leiden, Netherlands
    BMJ 328:261. 2004
  3. ncbi request reprint The Cochrane Fertility Regulation Group: synthesizing the best evidence about family planning
    Frans M Helmerhorst
    Fertility Regulation Group of the Cochrane Collaboration, Division of Reproductive Medicine, Department of Gynaecology, Leiden University Medical Center, Leiden, The Netherlands
    Contraception 74:280-6. 2006
  4. ncbi request reprint Intrauterine insemination versus timed intercourse for cervical hostility in subfertile couples
    Frans M Helmerhorst
    Department of Gynaecology, Division of Reproductive Medicine, Leiden University Medical Center, Leiden, The Netherlands
    Obstet Gynecol Surv 61:402-14; quiz 423. 2006
  5. doi request reprint Perinatal outcome, health, growth, and medical care utilization of 5- to 8-year-old intracytoplasmic sperm injection singletons
    Marjolein Knoester
    Department of Pediatrics, Neonatal Center, Leiden University Medical Center, Leiden, The Netherlands
    Fertil Steril 89:1133-46. 2008
  6. ncbi request reprint Cognitive development of singletons born after intracytoplasmic sperm injection compared with in vitro fertilization and natural conception
    Marjolein Knoester
    Department of Pediatrics, Neonatal Center, Leiden University Medical Center, Leiden, The Netherlands
    Fertil Steril 90:289-96. 2008
  7. doi request reprint The effect of different hormonal contraceptives on plasma levels of free protein S and free TFPI
    Marjolein Raps
    Marjolein Raps, Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
    Thromb Haemost 109:606-13. 2013
  8. ncbi request reprint The effect of the levonorgestrel-releasing intrauterine system on the resistance to activated protein C (APC)
    Huib A A M van Vliet
    Department of Gynaecology and Reproductive Medicine, Leiden University Medical Center, Leiden, The Netherlands
    Thromb Haemost 101:691-5. 2009
  9. doi request reprint The risk of deep venous thrombosis associated with injectable depot-medroxyprogesterone acetate contraceptives or a levonorgestrel intrauterine device
    Astrid van Hylckama Vlieg
    Department of Clinical Epidemiology, Leiden University Medical Center, C7 P, PO Box 9600, NL 2300 RC Leiden, The Netherlands
    Arterioscler Thromb Vasc Biol 30:2297-300. 2010
  10. doi request reprint Pericellular-acting proteases in human first trimester decidua
    Margreet Plaisier
    Division of Reproductive Medicine, Department of Gynaecology, Leiden University Medical Centre, PO Box 9600, 2300 RC, Leiden, The Netherlands
    Mol Hum Reprod 14:41-51. 2008

Collaborators

Detail Information

Publications28

  1. pmc The OPTIMIST study: optimisation of cost effectiveness through individualised FSH stimulation dosages for IVF treatment. A randomised controlled trial
    Theodora C van Tilborg
    Department of Reproductive Medicine and Gynaecology, University Medical Centre Utrecht, University of Utrecht, Utrecht, The Netherlands
    BMC Womens Health 12:29. 2012
    ..The aim of the present study is to assess whether an individualised FSH dose regime based on an ovarian reserve test (ORT) is more cost-effective than a standard dose regime...
  2. pmc Perinatal outcome of singletons and twins after assisted conception: a systematic review of controlled studies
    Frans M Helmerhorst
    Department of Obstetrics, Gynaecology and Reproductive Medicine, Leiden University Medical Center, NL 2300 Leiden, Netherlands
    BMJ 328:261. 2004
    ..To compare the perinatal outcome of singleton and twin pregnancies between natural and assisted conceptions...
  3. ncbi request reprint The Cochrane Fertility Regulation Group: synthesizing the best evidence about family planning
    Frans M Helmerhorst
    Fertility Regulation Group of the Cochrane Collaboration, Division of Reproductive Medicine, Department of Gynaecology, Leiden University Medical Center, Leiden, The Netherlands
    Contraception 74:280-6. 2006
    ..Systematic reviews of evidence, with an emphasis on randomized controlled trials when available, will continue to improve fertility regulation in the years ahead...
  4. ncbi request reprint Intrauterine insemination versus timed intercourse for cervical hostility in subfertile couples
    Frans M Helmerhorst
    Department of Gynaecology, Division of Reproductive Medicine, Leiden University Medical Center, Leiden, The Netherlands
    Obstet Gynecol Surv 61:402-14; quiz 423. 2006
    ....
  5. doi request reprint Perinatal outcome, health, growth, and medical care utilization of 5- to 8-year-old intracytoplasmic sperm injection singletons
    Marjolein Knoester
    Department of Pediatrics, Neonatal Center, Leiden University Medical Center, Leiden, The Netherlands
    Fertil Steril 89:1133-46. 2008
    ..To evaluate short- and long-term health in intracytoplasmic sperm injection (ICSI) singletons...
  6. ncbi request reprint Cognitive development of singletons born after intracytoplasmic sperm injection compared with in vitro fertilization and natural conception
    Marjolein Knoester
    Department of Pediatrics, Neonatal Center, Leiden University Medical Center, Leiden, The Netherlands
    Fertil Steril 90:289-96. 2008
    ..To investigate cognitive development of singletons conceived by intracytoplasmic sperm injection (ICSI) at 5-8 years of age...
  7. doi request reprint The effect of different hormonal contraceptives on plasma levels of free protein S and free TFPI
    Marjolein Raps
    Marjolein Raps, Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
    Thromb Haemost 109:606-13. 2013
    ..The effect of oral contraceptives on TFPI and PS is a possible explanation for the increased risk of venous thrombosis associated with oral contraceptives...
  8. ncbi request reprint The effect of the levonorgestrel-releasing intrauterine system on the resistance to activated protein C (APC)
    Huib A A M van Vliet
    Department of Gynaecology and Reproductive Medicine, Leiden University Medical Center, Leiden, The Netherlands
    Thromb Haemost 101:691-5. 2009
    ..48; 95% CI -0.85 to -2.11). In this study we observed that the levonorgestrel-intrauterine system decreases the resistance to APC which indicates that the levonorgestrel-intrauterine system does not have a prothrombotic effect...
  9. doi request reprint The risk of deep venous thrombosis associated with injectable depot-medroxyprogesterone acetate contraceptives or a levonorgestrel intrauterine device
    Astrid van Hylckama Vlieg
    Department of Clinical Epidemiology, Leiden University Medical Center, C7 P, PO Box 9600, NL 2300 RC Leiden, The Netherlands
    Arterioscler Thromb Vasc Biol 30:2297-300. 2010
    ....
  10. doi request reprint Pericellular-acting proteases in human first trimester decidua
    Margreet Plaisier
    Division of Reproductive Medicine, Department of Gynaecology, Leiden University Medical Centre, PO Box 9600, 2300 RC, Leiden, The Netherlands
    Mol Hum Reprod 14:41-51. 2008
    ..These data are consistent with a differential regulation of pericellular proteases in decidua by pregnancy-induced hormones, immune cells and EVT...
  11. ncbi request reprint Matched follow-up study of 5-8 year old ICSI-singletons: comparison of their neuromotor development to IVF and naturally conceived singletons
    Marjolein Knoester
    Department of Paediatrics, Neonatal Center, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
    Hum Reprod 22:1638-46. 2007
    ..Intracytoplasmic sperm injection (ICSI) is an invasive technique of artificial reproduction. We investigated the effect of ICSI on neuromotor development in 5-8 year old singletons...
  12. doi request reprint Screening for unrecognized coeliac disease in subfertile couples
    Caroline E Hogen Esch
    Department of Paediatric Gastroenterology, Leiden University Medical Center, Leiden, Netherlands
    Scand J Gastroenterol 46:1423-8. 2011
    ..We aimed to determine the prevalence of unrecognized CD in subfertile male-female couples visiting a fertility clinic compared with the general population...
  13. ncbi request reprint Quadriphasic versus monophasic oral contraceptives for contraception
    Huib Aam Van Vliet
    Department of Gynaecology, Division of Reproductive Medicine, Leiden University Medical Center, PO Box 9600, Albinusdreef 2, Leiden, Netherlands, NL 2300 RC
    Cochrane Database Syst Rev 11:CD009038. 2011
    ....
  14. ncbi request reprint An analysis of systematic reviews indicated low incorpororation of results from clinical trial quality assessment
    Anton J M de Craen
    Department of General Internal Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
    J Clin Epidemiol 58:311-3. 2005
    ..We investigated the frequency of quality assessment of randomized controlled trials within systematic reviews and the incorporation of the quality assessment in the analysis...
  15. doi request reprint Vaginal misoprostol prior to insertion of an intrauterine device: an RCT
    Kirsten Dijkhuizen
    Department of Gynaecology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
    Hum Reprod 26:323-9. 2011
    ..Here, we investigate whether vaginal misoprostol administered prior to intrauterine device (IUD) insertion reduces the number of failed insertions, insertion-related complications and pain during insertion...
  16. ncbi request reprint Triphasic versus monophasic oral contraceptives for contraception
    Huib Aam Van Vliet
    Department of Gynaecology, Division of Reproductive Medicine, Leiden University Medical Center, PO Box 9600, Leiden, Netherlands, 2300 RC
    Cochrane Database Syst Rev 11:CD003553. 2011
    ..Whether triphasic OCs have higher accidental pregnancy rates than monophasic pills is unknown. Nor is it known if triphasic pills give better cycle control and fewer side effects than the monophasic pills...
  17. ncbi request reprint Sensitivity to activated protein C during the menstrual cycle in women with and without factor VLeiden
    Huib A A M van Vliet
    Department of Gynaecology, Division of Reproductive Medicine, Leiden University Medical Center, P O Box 9600, 2300 RC Leiden, The Netherlands
    Thromb Res 121:757-61. 2008
    ..The aim of the study was to evaluate whether varying levels of estradiol and progesterone during the menstrual cycle are associated with differences in sensitivity to APC...
  18. ncbi request reprint Conventional in vitro fertilization versus intracytoplasmic sperm injection in patients with borderline semen: a randomized study using sibling oocytes
    Lucette van der Westerlaken
    Department of Reproductive Medicine, Leiden University Medical Center, Leiden, The Netherlands
    Fertil Steril 85:395-400. 2006
    ..To determine whether patients with borderline semen should be treated with conventional IVF or intracytoplasmic sperm injection (ICSI)...
  19. ncbi request reprint Different degrees of vascularization and their relationship to the expression of vascular endothelial growth factor, placental growth factor, angiopoietins, and their receptors in first-trimester decidual tissues
    Margreet Plaisier
    Department of Biomedical Research, TNO Quality of Life, Leiden, The Netherlands
    Fertil Steril 88:176-87. 2007
    ..Comparison of these tissues provides information about the regulation of vascularization by pregnancy-induced hormones and/or the extravillous trophoblast (EVT)...
  20. ncbi request reprint Thrombophilias and gynaecology
    Kitty W M Bloemenkamp
    Department of Obstetrics, Gynaecology and Reproductive Medicine, Leiden University Medical Center, P O Box 9600, RC 2300, Leiden, The Netherlands
    Best Pract Res Clin Obstet Gynaecol 17:509-28. 2003
    ..Emerging studies show that in vitro fertilization treatment and ovulation induction are also risk factors for venous thrombosis; the role of coagulation defects in this association is not yet clear...
  21. ncbi request reprint Retention of estradiol negative feedback relationship to LH predicts ovulation in response to caloric restriction and weight loss in obese patients with polycystic ovary syndrome
    Eveline W C M van Dam
    Department of General Internal Medicine, Leiden University Medical Center, C1 R39, 2300 RC Leiden, The Netherlands
    Am J Physiol Endocrinol Metab 286:E615-20. 2004
    ..We infer that evidence of retention of estradiol-dependent negative feedback on LH secretion may forecast follicle maturation and ovulation in obese patients with PCOS under dietary restriction...
  22. ncbi request reprint Increase in daily LH secretion in response to short-term calorie restriction in obese women with PCOS
    Eveline W C M van Dam
    Department of Endocrinology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
    Am J Physiol Endocrinol Metab 282:E865-72. 2002
    ..Enhanced LH secretion in the presence of normal metabolic and hormonal adaptations to calorie restriction points to anomalous feedback control of pituitary LH release in PCOS...
  23. pmc How many eggs?
    Marc J N C Keirse
    BMJ 329:302-3. 2004
  24. ncbi request reprint Injection of embryo culture supernatant prior to blastocyst transfer--cofactor?
    Kitty Kapiteijn
    Fertil Steril 89:1027-8; author reply 1028. 2008
  25. ncbi request reprint Combination estrogen-progestin contraceptives and body weight: systematic review of randomized controlled trials
    Maria F Gallo
    Family Health International, Research Triangle Park, North Carolina, USA
    Obstet Gynecol 103:359-73. 2004
    ..This concern can deter women from starting hormonal contraception or lead to premature quitting. This review evaluated the association between combination contraceptive use and change in body weight...
  26. ncbi request reprint The value of Chlamydia trachomatis-specific IgG antibody testing and hysterosalpingography for predicting tubal pathology and occurrence of pregnancy
    Denise A M Perquin
    Department of Obstetrics and Gynecology, Medical Center Haaglanden, The Hague, The Netherlands
    Fertil Steril 88:224-6. 2007
    ..The diagnostic accuracy and prognostic value of both C. trachomatis-specific IgG antibody testing and HSG are comparable but show poor performance...
  27. ncbi request reprint Biphasic versus triphasic oral contraceptives for contraception
    Hubertus A A M van Vliet
    Family Health International, Research Triangle Park, NC 27709, USA
    Contraception 65:321-4. 2002
    ..This suggests that the choice of progestin may be more important that the phasic regimen in determining bleeding patterns...
  28. ncbi request reprint Biphasic versus monophasic oral contraceptives for contraception: a Cochrane review
    Hubertus A A M van Vliet
    Family Health International, P O Box 13950, Research Triangle Park, North Carolina 27709, USA
    Hum Reprod 17:870-3. 2002
    ....