Cees Renckens - Academia.edu (original) (raw)
Papers by Cees Renckens
Nederlands tijdschrift voor geneeskunde, 2007
Human …, 2011
METHODS In 38 centres, we prospectively studied a cohort of patients referred for subfertility be... more METHODS In 38 centres, we prospectively studied a cohort of patients referred for subfertility between 2002 and 2004, who underwent HSG and/or laparoscopy as part of their subfertility work-up. Follow-up started immediately after tubal testing and ended 12 months ...
The World Health Organization once again advocates for implementing complementary and alternative... more The World Health Organization once again advocates for implementing complementary and alternative medicine in national health services, jeopardizing global public health and evidence-based medicine.
Fertility and sterility, 1984
From 1967 to 1973 serum samples of 1709 infertile women were tested for antispermatozoal antibodi... more From 1967 to 1973 serum samples of 1709 infertile women were tested for antispermatozoal antibodies with the gelatin agglutination test. In 110 cases sperm agglutinins were demonstrated in titers ranging from 4 to 1024. The clinical data of 99 couples were evaluable, and in 65 there appeared to be unexplained infertility. Out of these 65 women, 44 became pregnant in the posttesting follow-up period of 6 to 13.5 years (median, 10 years). With increasing titers there was a significant decrease in the probability of becoming pregnant. Of the women who became pregnant, in general, those with higher titers had to wait longer for their pregnancy than those with lower titers. Moreover, with increasing titers there was a tendency toward a longer duration of infertility before the serum was tested. This latter observation supports the contention that the agglutinin titer influences the fecundability rate. The titers of those becoming pregnant and those remaining infertile, however, showed co...
Fertility and sterility, 1984
Fertility and Sterility, 2010
Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in su... more Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in subfertile couples. Design: A prospective cohort study. Setting: The study was conducted in 38 fertility centers in the Netherlands. Patient(s): Subfertile couples who miscarried after completing their basic fertility work-up. Intervention(s): Expectant management after a miscarriage. Main Outcome Measure(s): Spontaneous ongoing pregnancy. Result(s): We included 5,663 subfertile couples, of which 1,098 (19%) conceived spontaneously. Among these 1,098 couples, 199 (18%) miscarried and these couples were included in the present study. Follow-up was completed for 171 couples, of which 95 conceived again within 24 months of follow-up. Of these 95 pregnancies, 86 (91%) were ongoing. The cumulative spontaneous ongoing pregnancy rate (PR) after 24 months was 70% (95% confidence interval [CI] 59%-81%). Conclusion(s): Subfertile couples, who experience a treatment-independent pregnancy resulting in a miscarriage, have very good prospects of a spontaneous ongoing pregnancy in the near future. This information is useful in counseling couples who had a miscarriage after a previous period of subfertility. (Fertil Steril Ò 2010;94:485-8.
Nederlands tijdschrift voor geneeskunde, Jan 6, 2007
Evaluation & the Health Professions, 2009
Between 1986 and 2003, research efforts on complementary and alternative medicine (CAM) were subs... more Between 1986 and 2003, research efforts on complementary and alternative medicine (CAM) were subsidized by the Dutch government. This led to 12 academic theses and a considerable number of papers in medical journals. In our review, we have summarized the results of this research, grouped by therapeutic category (that is, acupuncture, paranormal therapies, naturopathy, manual therapies, homeopathy and anthroposophical medicine.) Of the 12 theses, four were written in Dutch, three of which were not subsequently published in peer-reviewed journals, while the fourth, on enzyme therapy, led to a number of papers in Dutch medical journals. In three instances, mildly positive findings were reported: on the efficacy of manual therapies, the use of acupuncture analgesia in surgery, and an elimination diet against migraine and tension headaches. These positive conclusions can easily be explained by methodological shortcomings (e.g., not using credible placebo-control groups); in the other nine theses, the researchers themselves had drawn negative conclusions. The Dutch government ended its financial support for CAM research in 2006.
Evaluation & the Health Professions, 2009
Discontentment with the massive violations of the influential Dutch Prime Minister&am... more Discontentment with the massive violations of the influential Dutch Prime Minister's (Johan Rudolf Thorbecke) health laws led to the foundation of the Dutch Society Against Quackery, in 1880. Within a few years, the Society had more than 1,100 members. Initially, quackery mostly consisted of the unauthorized practice of medicine and the peddling of industrially manufactured ''secret remedies.'' Since the 50s however, the energy of the society focused mainly on magnetizers, especially after they gained support from the field of parapsychology, lay manipulators of the back and herb doctors. The most important object of the society since 1980 has been the fight against the so-called alternative medicine, of which Chinese acupuncture, homeopathy, manipulative therapy, anthroposophical medicine, and naturopathy are prominent targets. Despite numerous costly lawsuits, the society still survives and is probably the oldest as well as the largest of its kind in the world.
Nederlands tijdschrift voor geneeskunde, 2010
The Dutch parliament has recently accepted a tax law in which certain groups of alternative thera... more The Dutch parliament has recently accepted a tax law in which certain groups of alternative therapists can be exempt from VAT. To be eligible for this VAT exemption, the disciplines to which the therapists belong have to meet certain training requirements. In this article it is contended, in agreement with the Royal College of Physicians in the UK, that statutory regulation is inappropriate for disciplines whose therapies are neither of proved benefit nor appropriately tested. It legitimizes harmful therapies. This is illustrated by two serious accidents, previously described in this journal, caused by a chiropractor and a craniosacral therapist.
BJOG : an international journal of obstetrics and gynaecology, 2006
Tropical Medicine & International Health, 2012
Human Reproduction, 2012
background: We recently reported that treatment with intrauterine insemination and controlled ova... more background: We recently reported that treatment with intrauterine insemination and controlled ovarian stimulation (IUI-COS) did not increase ongoing pregnancy rates compared with expectant management (EM) in couples with unexplained subfertility and intermediate prognosis of natural conception. Long-term cost-effectiveness of a policy of initial EM is unknown. We investigated whether the recommendation not to treat during the first 6 months is valid, regarding the long-term effectiveness and cumulative costs. methods: Couples with unexplained subfertility and intermediate prognosis of natural conception (n ¼ 253, at 26 public clinics, the Netherlands) were randomly allocated to 6 months EM or immediate start with IUI-COS. The couples were then treated according to local protocol, usually IUI-COS followed by IVF. We followed couples until 3 years after randomization and registered pregnancies and resources used. Primary outcome was time to ongoing pregnancy. Secondary outcome was treatment costs. Analysis was by intentionto-treat. Economic evaluation was performed from the perspective of the health care institution.
Fertility and Sterility, 2010
Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in su... more Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in subfertile couples. Design: A prospective cohort study. Setting: The study was conducted in 38 fertility centers in the Netherlands. Patient(s): Subfertile couples who miscarried after completing their basic fertility work-up. Intervention(s): Expectant management after a miscarriage. Main Outcome Measure(s): Spontaneous ongoing pregnancy. Result(s): We included 5,663 subfertile couples, of which 1,098 (19%) conceived spontaneously. Among these 1,098 couples, 199 (18%) miscarried and these couples were included in the present study. Follow-up was completed for 171 couples, of which 95 conceived again within 24 months of follow-up. Of these 95 pregnancies, 86 (91%) were ongoing. The cumulative spontaneous ongoing pregnancy rate (PR) after 24 months was 70% (95% confidence interval [CI] 59%-81%). Conclusion(s): Subfertile couples, who experience a treatment-independent pregnancy resulting in a miscarriage, have very good prospects of a spontaneous ongoing pregnancy in the near future. This information is useful in counseling couples who had a miscarriage after a previous period of subfertility. (Fertil Steril Ò 2010;94:485-8.
BJOG: An International Journal of Obstetrics & Gynaecology, 2005
The World Health Organization once again advocates for implementing complementary and alternative... more The World Health Organization once again advocates for implementing complementary and alternative medicine in national health services, jeopardizing global public health and evidence-based medicine.
Nederlands tijdschrift voor geneeskunde, 2007
Human …, 2011
METHODS In 38 centres, we prospectively studied a cohort of patients referred for subfertility be... more METHODS In 38 centres, we prospectively studied a cohort of patients referred for subfertility between 2002 and 2004, who underwent HSG and/or laparoscopy as part of their subfertility work-up. Follow-up started immediately after tubal testing and ended 12 months ...
The World Health Organization once again advocates for implementing complementary and alternative... more The World Health Organization once again advocates for implementing complementary and alternative medicine in national health services, jeopardizing global public health and evidence-based medicine.
Fertility and sterility, 1984
From 1967 to 1973 serum samples of 1709 infertile women were tested for antispermatozoal antibodi... more From 1967 to 1973 serum samples of 1709 infertile women were tested for antispermatozoal antibodies with the gelatin agglutination test. In 110 cases sperm agglutinins were demonstrated in titers ranging from 4 to 1024. The clinical data of 99 couples were evaluable, and in 65 there appeared to be unexplained infertility. Out of these 65 women, 44 became pregnant in the posttesting follow-up period of 6 to 13.5 years (median, 10 years). With increasing titers there was a significant decrease in the probability of becoming pregnant. Of the women who became pregnant, in general, those with higher titers had to wait longer for their pregnancy than those with lower titers. Moreover, with increasing titers there was a tendency toward a longer duration of infertility before the serum was tested. This latter observation supports the contention that the agglutinin titer influences the fecundability rate. The titers of those becoming pregnant and those remaining infertile, however, showed co...
Fertility and sterility, 1984
Fertility and Sterility, 2010
Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in su... more Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in subfertile couples. Design: A prospective cohort study. Setting: The study was conducted in 38 fertility centers in the Netherlands. Patient(s): Subfertile couples who miscarried after completing their basic fertility work-up. Intervention(s): Expectant management after a miscarriage. Main Outcome Measure(s): Spontaneous ongoing pregnancy. Result(s): We included 5,663 subfertile couples, of which 1,098 (19%) conceived spontaneously. Among these 1,098 couples, 199 (18%) miscarried and these couples were included in the present study. Follow-up was completed for 171 couples, of which 95 conceived again within 24 months of follow-up. Of these 95 pregnancies, 86 (91%) were ongoing. The cumulative spontaneous ongoing pregnancy rate (PR) after 24 months was 70% (95% confidence interval [CI] 59%-81%). Conclusion(s): Subfertile couples, who experience a treatment-independent pregnancy resulting in a miscarriage, have very good prospects of a spontaneous ongoing pregnancy in the near future. This information is useful in counseling couples who had a miscarriage after a previous period of subfertility. (Fertil Steril Ò 2010;94:485-8.
Nederlands tijdschrift voor geneeskunde, Jan 6, 2007
Evaluation & the Health Professions, 2009
Between 1986 and 2003, research efforts on complementary and alternative medicine (CAM) were subs... more Between 1986 and 2003, research efforts on complementary and alternative medicine (CAM) were subsidized by the Dutch government. This led to 12 academic theses and a considerable number of papers in medical journals. In our review, we have summarized the results of this research, grouped by therapeutic category (that is, acupuncture, paranormal therapies, naturopathy, manual therapies, homeopathy and anthroposophical medicine.) Of the 12 theses, four were written in Dutch, three of which were not subsequently published in peer-reviewed journals, while the fourth, on enzyme therapy, led to a number of papers in Dutch medical journals. In three instances, mildly positive findings were reported: on the efficacy of manual therapies, the use of acupuncture analgesia in surgery, and an elimination diet against migraine and tension headaches. These positive conclusions can easily be explained by methodological shortcomings (e.g., not using credible placebo-control groups); in the other nine theses, the researchers themselves had drawn negative conclusions. The Dutch government ended its financial support for CAM research in 2006.
Evaluation & the Health Professions, 2009
Discontentment with the massive violations of the influential Dutch Prime Minister&am... more Discontentment with the massive violations of the influential Dutch Prime Minister's (Johan Rudolf Thorbecke) health laws led to the foundation of the Dutch Society Against Quackery, in 1880. Within a few years, the Society had more than 1,100 members. Initially, quackery mostly consisted of the unauthorized practice of medicine and the peddling of industrially manufactured ''secret remedies.'' Since the 50s however, the energy of the society focused mainly on magnetizers, especially after they gained support from the field of parapsychology, lay manipulators of the back and herb doctors. The most important object of the society since 1980 has been the fight against the so-called alternative medicine, of which Chinese acupuncture, homeopathy, manipulative therapy, anthroposophical medicine, and naturopathy are prominent targets. Despite numerous costly lawsuits, the society still survives and is probably the oldest as well as the largest of its kind in the world.
Nederlands tijdschrift voor geneeskunde, 2010
The Dutch parliament has recently accepted a tax law in which certain groups of alternative thera... more The Dutch parliament has recently accepted a tax law in which certain groups of alternative therapists can be exempt from VAT. To be eligible for this VAT exemption, the disciplines to which the therapists belong have to meet certain training requirements. In this article it is contended, in agreement with the Royal College of Physicians in the UK, that statutory regulation is inappropriate for disciplines whose therapies are neither of proved benefit nor appropriately tested. It legitimizes harmful therapies. This is illustrated by two serious accidents, previously described in this journal, caused by a chiropractor and a craniosacral therapist.
BJOG : an international journal of obstetrics and gynaecology, 2006
Tropical Medicine & International Health, 2012
Human Reproduction, 2012
background: We recently reported that treatment with intrauterine insemination and controlled ova... more background: We recently reported that treatment with intrauterine insemination and controlled ovarian stimulation (IUI-COS) did not increase ongoing pregnancy rates compared with expectant management (EM) in couples with unexplained subfertility and intermediate prognosis of natural conception. Long-term cost-effectiveness of a policy of initial EM is unknown. We investigated whether the recommendation not to treat during the first 6 months is valid, regarding the long-term effectiveness and cumulative costs. methods: Couples with unexplained subfertility and intermediate prognosis of natural conception (n ¼ 253, at 26 public clinics, the Netherlands) were randomly allocated to 6 months EM or immediate start with IUI-COS. The couples were then treated according to local protocol, usually IUI-COS followed by IVF. We followed couples until 3 years after randomization and registered pregnancies and resources used. Primary outcome was time to ongoing pregnancy. Secondary outcome was treatment costs. Analysis was by intentionto-treat. Economic evaluation was performed from the perspective of the health care institution.
Fertility and Sterility, 2010
Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in su... more Objective: To assess the time to spontaneous ongoing pregnancy after a previous miscarriage in subfertile couples. Design: A prospective cohort study. Setting: The study was conducted in 38 fertility centers in the Netherlands. Patient(s): Subfertile couples who miscarried after completing their basic fertility work-up. Intervention(s): Expectant management after a miscarriage. Main Outcome Measure(s): Spontaneous ongoing pregnancy. Result(s): We included 5,663 subfertile couples, of which 1,098 (19%) conceived spontaneously. Among these 1,098 couples, 199 (18%) miscarried and these couples were included in the present study. Follow-up was completed for 171 couples, of which 95 conceived again within 24 months of follow-up. Of these 95 pregnancies, 86 (91%) were ongoing. The cumulative spontaneous ongoing pregnancy rate (PR) after 24 months was 70% (95% confidence interval [CI] 59%-81%). Conclusion(s): Subfertile couples, who experience a treatment-independent pregnancy resulting in a miscarriage, have very good prospects of a spontaneous ongoing pregnancy in the near future. This information is useful in counseling couples who had a miscarriage after a previous period of subfertility. (Fertil Steril Ò 2010;94:485-8.
BJOG: An International Journal of Obstetrics & Gynaecology, 2005
The World Health Organization once again advocates for implementing complementary and alternative... more The World Health Organization once again advocates for implementing complementary and alternative medicine in national health services, jeopardizing global public health and evidence-based medicine.