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N Naaktgeboren

Publications and source records attributed to N Naaktgeboren.

At least 19 recordsLinked to original sources
PubMed2002

[Results of in vitro fertilization in the Netherlands, 1996-2000].

OBJECTIVE: To describe the annual results in all 13 Dutch in vitro fertilisation (IVF) centres in the period 1996-2000, and to look for possible differences between individual centres and years. DESIGN: Retrospective data collection, description and analysis. METHOD: The results collected on the website of the Dutch Society of Obstetrics and Gynaecology (Dutch acronym: NVOG; www.nvog.nl) in the period 1996-2000 were integrated and described, with special attention to possible differences between centres and years. RESULTS: In 1996-2000 (5 years), 63,414 IVF or ICSI treatment cycles were started in the Netherlands, and 5,884 transfers of cryopreserved embryos were performed. The number of treatment cycles increased over the years, particularly the number of ICSI cycles. The total number of ongoing pregnancies was 12,991 (20.5% per started cycle; 22.5% for ICSI and 18.3% for IVF). Particularly during the first 3 years, there was an increase in these percentages (IVF: from 16.4% (1996) to 19.2% (1998); ICSI: from 18.3% (1996) to 23.9% (1998)). There were differences between the centres in both the percentage of ongoing pregnancies per started IVF/ICSI cycle (range 13.7-25.1%) and the percentage ICSI (14-61%) and cryo-transfers per total number of treatment cycles (0-26%). It was estimated that, during this 5-year period, 1 out of every 61 Dutch neonates resulted from IVF or ICSI. CONCLUSION: The pregnancy-rates after IVF and ICSI increased during the study period, and were comparable with the rates in other European countries. Some important data are still missing from the inventory, for example regarding the number of embryos per transfer, multiple pregnancies, live births, congenital malformations and complications.

Embryo Transfer↗
PubMed2000

Obstetric outcome of singleton pregnancies after IVF: a matched control study in four Dutch university hospitals.

In singleton pregnancies after IVF a high rate of preterm deliveries and an increased rate of small-for-gestational age (SGA) children in comparison to the general parturient population have been reported. However, due to differences between IVF mothers and their peers who conceived naturally, careful selection of the control group is necessary to assess whether IVF pregnancies really carry increased risks of adverse outcome. In our study 307 IVF pregnancies were compared with 307 control pregnancies after elaborate matching for an extensive number of maternal characteristics, as well as for the hospital that provided the obstetric care. Four Dutch university hospitals contributed to the study. In cases with spontaneous onset of labour, gestational age at delivery was 3 days shorter in the IVF group (275 versus 278 days, P = 0.05). The proportion of SGA was higher in the IVF group (16.2 versus 7.9%, P < 0.001). The combination of these two results denotes a distinct difference between IVF and control pregnancies. Placental weight was comparable in both groups.

Abnormalities, Multiple↗
PubMed1999

[Pregnancy course and outcome in 2956 pregnancies after in-vitro fertilization in Netherlands].

OBJECTIVE: Description of the outcome of pregnancies after in vitro fertilisation (IVF) in Dutch IVF centers. DESIGN: Descriptive, retrospective. METHOD: Data were collected on IVF pregnancies in the period 1984-1992 from seven Dutch IVF centers. RESULTS: The study comprised 2956 pregnancies. Five centres provided data on 2133 ongoing and non-ongoing pregnancies. More than 25% ended in a spontaneous abortion (22.3%) or ectopic pregnancy (3.6%). From the seven centres there were data available on 2311 ongoing pregnancies. Of these, 30.8% were multiple; preterm delivery occurred in 29.2%. The birth weight of 40.6% of 3173 neonates was lower than 2500 g and that of 10.1% lower than 1500 g. A birth weight under the 10th percentile of the national reference curve was found in 16.7% and under the 2.3rd percentile in 4.3% of cases. Perinatal mortality was 31.3 pro mille. In 1588 singleton pregnancies preterm birth occurred in 15.6%; 41.3% of the singletons weighed less than 2500 g, of which 3.6% less than 1500 g while 12.3% had a birth weight below the 10th percentile. The results of our study are similar to those of other major studies in the literature and are unfavourable compared with to Dutch reference values. This is mainly due to the high proportion of multiple pregnancies. However, we found indications of a slight disturbance of pregnancy in IVF singleton and twin pregnancies.

Adult↗
PubMed1999

Intracytoplasmic sperm injection: position of the polar body affects pregnancy rate.

A prospective study on intracytoplasmic sperm injection (ICSI) was performed to evaluate the effect of the position of the polar body relative to the opening of the injection needle during sperm injection, and of the person who performs the injections on fertilization, cleavage, and pregnancy rates. This study included 173 couples undergoing 313 ICSI cycles from September 1995 to December 1997. All injections were performed by two persons. For each injected oocyte the person who performed the injection was recorded as well as the position of the polar body during injection (6 o'clock: animal pole towards the opening of the needle; 12 o'clock: animal pole away from the opening of the needle). Of 2630 oocytes retrieved, 2232 were injected. Significantly more oocytes developed two pronuclei after injection with the polar body at 6 o'clock versus 12 o'clock (P = 0.01; 51 versus 45% respectively) and after injection by person 1 versus person 2 (P = 0.02; 50 and 45% respectively). Higher pregnancy rate (P = 0.046) was found after transfer of embryos from oocytes injected with the polar body at 6 o'clock (36%) versus 12 o'clock (18%). This was the result of a significant interaction (P = 0.03) between the position of the polar body and the person performing the injections. Given the higher fertilization rate in the 6 o'clock group, it is recommended that oocytes be injected with the polar body at 6 o'clock. The higher pregnancy rate as a result of polar body position and the interaction between polar body position and the operator suggest variations in injection technique.

Adult↗
PubMed1998

Evaluation of pregnancy rates after intrauterine insemination according to indication, age, and sperm parameters.

PURPOSE: Our purpose was to evaluate intrauterine insemination results obtained in our clinic and identify prognostic factors for the chance of pregnancy. METHODS: A retrospective study of data from 1989 to 1996 was undertaken. Only first attempts were included in this study, except for the part on the cumulative pregnancy rates. Couples with either one-sided tubapathology, hormonal dysfunction, idiopathic infertility, or andrological indication were selected. All women were stimulated with clomiphene citrate. Five hundred sixty-six couples who underwent 1763 cycles were included in the study. RESULTS: The overall pregnancy rate for first pregnancies was 6.9% per cycle and 21.4% per patient. For first intrauterine insemination attempts this was 8.8% per cycle/patient, varying between 5.0% for andrological indication and 10.6% for tubapathology, 10.0% for idiopatic indication, and 10.3% for hormonal indication. These differences were not significant. Age did not have a significant effect either, although there were no pregnancies observed in women 40 years or older. The number of inseminated spermatozoa significantly affected the pregnancy rate: < 2 million, 4.6%; > or = 2 to < 10 million, 3.9%; and > or = 10 million, 11.3%. CONCLUSIONS: Unless semen characteristics are insufficient, intrauterine insemination is a useful treatment for infertile couples.

Adult↗
PubMed1997

Donor insemination: Dutch parents' opinions about confidentiality and donor anonymity and the emotional adjustment of their children.

Results from a comparative study investigating 38 donor insemination (DI) Dutch families with 4-8 year old children are presented. The aims of this study were to investigate parents' opinions on the issues of confidentiality and donor anonymity, to assess the emotional development of the children, and to examine in DI families the association between secrecy with regard to the use of a donor and the emotional adjustment of the children. The DI families were compared to families with a child conceived by in-vitro fertilization (IVF) and to families with a naturally conceived child. Secrecy appeared to be associated with DI and not with IVF: 74% of the DI parents intended not to inform the child about the way in which she/he was conceived, whereas none of the IVF parents intended to keep the secret. Only one set of DI parents and two sets of IVF parents had actually told the child. As to donor anonymity, a spread of opinions appeared among DI parents; 57% preferred an anonymous donor, 31% would have liked non-identifying information about the donor, 9% preferred the donor's identity to be registered and 3% remained unsure. Parents' major concern was to know more about the medical/genetic background of the donor. Mothers and fathers in the DI families differed in their opinions concerning the issues of confidentiality and donor anonymity: fathers, more often than mothers, were secretive with regard to the use of a donor and husbands, more often than their wives, were in favour of donor anonymity. With regard to the emotional development of the children, more emotional/behavioural problems were revealed among DI children than among children who were naturally conceived. No association was found between secrecy and the emotional/behavioural adjustment of the children.

Affective Symptoms↗
PubMed1996

Vastatins have a distinct effect on sterol synthesis and progesterone secretion in human granulosa cells in vitro.

Lovastatin and simvastatin are strong inhibitors of cholesterol synthesis in cultured human granulosa cells, as measured within 6 days after isolation, with IC50-values of respectively 27.0 and 18.2 nM obtained after 3.5 hours of incubation with the drugs. Pravastatin is a much weaker inhibitor of cholesterol synthesis (IC50-value of 977.8 nM) in these cells. Under these conditions inhibition of cholesterol synthesis had no influence on progesterone secretion into the medium which was probably due to the presence of large cholesterol pools in the cells. To deplete these pools, granulosa cells were cultured for 7 days after which the culture medium was changed into medium supplemented with 20% lipoprotein-depleted serum to deprive the cells of exogenous cholesterol. Additionally, 30 mIU of follicle-stimulating hormone and luteinizing hormone per ml were added to stimulate the progesterone production and secretion, thereby decreasing the cholesteryl ester pools. After 48 h of incubation, culture was continued without hormones for another two days. Thereafter, the cells were preincubated for 24 h without or with 1 microM of lovastatin, simvastatin or pravastatin in medium containing lipoprotein-deficient serum and the above-mentioned hormones. This period is followed by incubation for another 24 h in the presence of [14C]acetate after which cells and media were collected for determination of 14C-labelled sterols synthesized and progesterone secreted into the media. Now, lovastatin and simvastatin, which strongly inhibited sterol synthesis, significantly attenuated the secretion of progesterone. One microM of pravastatin had no significant effect on sterol synthesis nor on progesterone secretion. When the latter experiment was performed under conditions in which exogenous cholesterol was provided in the form of human low density lipoproteins, no influence of the vastatins on progesterone secretion was observed. So under conditions in which the cholesterol pools were decreased, lovastatin and simvastatin attenuated the progesterone secretion, whereas pravastatin did not. When pools were filled by exogenous cholesterol, no effect on progesterone secretion by either of the drugs was observed.

Cells, Cultured↗
PubMed1996

Evaluation of the postcoital test for assessment of 'cervical factor' infertility.

OBJECTIVE: To evaluate the test properties of the postcoital test (PCT). STUDY DESIGN: Retrospective analysis of prospectively collected data on a cohort of infertile couples with complete follow up. SETTING: Fertility clinic of a Dutch university hospital. SUBJECTS: A continuous series of 224 couples of whom 24 were excluded for reasons of anovulation, coital problems, proven sterility or incomplete follow-up. ANALYSIS: Cumulative pregnancy rates in relation to PCT results with and without treatment for 'cervical factor' infertility. RESULTS: The predictive values of normal and abnormal PCTs were 0.54 and 0.58 overall and 0.74 and 0.47 if only untreated women were considered. Sensitivity and specificity were, respectively, 0.47 and 0.65 for all women and 0.54 and 0.68 for untreated women only. Likelihood ratios for normal and abnormal PCTs were 0.83 and 1.32 overall and 0.67 and 1.72 in untreated women. CONCLUSION: The PCT has poor predictive power. This and the psychological impact on subfertile couples attest to the need for more rigorous study designs in evaluating this test.

Adult↗
PubMed1996

In-vitro fertilization: the experience of treatment, pregnancy and delivery.

The present study compares the evidence of pregnancy and delivery among in-vitro fertilization (IVF) parents (45 couples), other formerly infertile parents (35 couples) and fertile parents (35 couples). All deliveries concerned primaparous women and singleton births. In addition, the burden of fertility treatments was investigated. Results show that the psychological burden of the treatments exceeds the physical burden. Fertility treatments were judged very worthwhile. Complications during pregnancy were more frequently reported by IVF mothers and other initially infertile mothers than by fertile mothers. However, controlling for the older age in both formerly infertile groups (IVF and non-IVF), no significant difference was found. No differences appeared regarding the evaluation of the development of the delivery. IVF parents and other infertile parents evaluated the pregnancy as more stressful than fertile parents. However, mothers experienced their delivery as more exceptional, and fathers experienced the pregnancy as more exceptional. In addition, IVF fathers enjoyed the pregnancy more than fathers from the other groups.

Female↗
PubMed1995

Follow-up of 30 pregnancies after embryo cryopreservation.

OBJECTIVE: In an observational follow-up study, the pregnancy outcome of the first 30 women who conceived after transfer of cryopreserved embryos was evaluated. STUDY DESIGN: The main outcome measures were duration and complications of pregnancy, mode of delivery, complications during and after childbirth, birthweight, Apgar score, and congenital anomalies. RESULTS: Twenty-six pregnancies ended in birth of one (n = 22) or more (n = 4) infants with a cesarean section rate of 23%. Of the singleton pregnancies 77% were uncomplicated, but there was a high incidence of breech presentation (14%). Infant birthweight tended to be above average with 45% of singletons weighing more than the 75th centile of weight for gestation. There were no major congenital deformations. CONCLUSION: The results of our embryo cryopreservation program are encouraging, but sustained follow-up of such pregnancies and infants is needed.

Adult↗
PubMed1994

Prostanoid levels in in vitro fertilization culture medium are not related to the likelihood of implantation.

OBJECTIVE: To determine prostanoid levels (prostaglandin E2, prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha, and thromboxane B2 [TXB2]) in embryo culture medium containing inactivated maternal serum and their correlation with the clinical outcome of IVF-ET. DESIGN: Prostanoid levels were measured in blank control medium and in medium containing an embryo or nonfertilized oocyte with a high-pressure liquid chromatography (HPLC-RIA) method. Comparisons of HPLC-RIA, Seppak C18-RIA, and RIA directly in the medium demonstrated identical results for TXB2, allowing the use of direct RIA in the large investigation of 129 media. SETTING: Leiden University Hospital, The Netherlands. PATIENTS: Patients with (n = 12) and without (n = 15) an ongoing pregnancy after IVF-ET. MAIN OUTCOME MEASURES: Prostanoid levels in embryo culture medium and relationship between prostanoid levels and successful implantation. RESULTS: Thromboxane B2 is the only prostanoid consistently found in these media. In both groups there was no difference in TXB2 levels between control media, media containing a nonfertilized oocyte, and media containing an embryo. There was no difference in TXB2 levels between media that had harbored the beginning of a successful pregnancy and those that had not produced a pregnancy. CONCLUSION: Thromboxane B2 in the embryo culture medium originates from maternal serum and bears no relationship with the likelihood of fertilization and implantation.

Chromatography, High Pressure Liquid↗
PubMed1991

Results of IVF from a prospective multicentre study.

Part of a cost-effectiveness study of in-vitro fertilization was the evaluation of the medical results of this fertility treatment. Data were prospectively collected from greater than 3000 IVF treatments in five Dutch hospitals during a 2-year period. The average 'take-at-least-one-healthy-baby-home-rate' per started treatment was 10% (the average clinical pregnancy rate per embryo transfer was 20%). After more IVF treatments, about one in three to four couples were successful. Differences in results were mainly caused by patient characteristics, the treatment episode and the treating hospital. These differences remained in a multivariate logistic regression analysis.

Cost-Benefit Analysis↗
PubMed1991

Selective drop-out in successive in-vitro fertilization attempts: the pendulum danger.

Success rates from in-vitro fertilization (IVF) in the long term are dependent on selection procedures with regard to continuation into further IVF episodes. Publications on success rates in successive episodes will give incentives to adapt selection criteria, but if these publications do not deal explicitly with patient selection, the adaptations might change their direction every time: the pendulum danger.

Female↗
PubMed1990

Comparison of ovarian stimulation regimens for in vitro fertilization (IVE) with and without a gonadotropin-releasing hormone (GnRH) agonist: results of a randomized study.

In order to diminish the cancellation rate due to a premature endogeneous LH surge and/or to a poor ovarian response and thus increasing the pregnancy rate, a GnRH agonist (Buserelin) was applied in patients starting their first ovarian stimulation with gonadotropins for IVF. All patients suffered from tubal infertility and were not older than 40 years. Each woman was allocated randomly to one of three groups: the conventional treatment with hMG alone (group I), patients from group II started the hMG treatment shortly after the LH rise caused by the GnRH agonist and patients in group III commenced the hMG treatment when an hypogonadotropic state was achieved after a long treatment of Buserelin. All male partners had a normal spermiogram. A reduction of poor responders to the superovulation is seen in the short-term group (6%), compared with the other two groups (14%). In some cases from group III ovarian cyst formation led to the cancellation of the treatment. The long-term group differs significantly from the other two in the duration of the gonadotropin stimulation and the number of ampoules hMG used. A severe ovarian overstimulation syndrome was not observed. There is no difference in the number of retrieved oocytes and the fertilization rate among the three groups. The pregnancy rate per cycle or per patient in the group with a short-term GnRH-agonist regimen is significantly higher compared to that of the group using the conventional hMG treatment.

Administration, Intranasal↗
PubMed1989

Is oxytocin present in platelets?

For arginine-vasopressin (AVP) it has been suggested that about 90% of the total amount present in peripheral blood is platelet-membrane bound. Oxytocin (OT) and AVP are nonapeptides which are similar in many respects. We investigated the possibility that OT might be found in platelet-rich plasma samples from patients undergoing ovarian super-stimulation for in-vitro fertilization purposes. These plasma samples were treated with acid repeated freezing/thawing and sonification in an attempt to solubilize or expose the possible bound OT. No differences between OT concentrations in platelet-rich or -poor plasma samples were found. We conclude that plasma OT is not bound or confined to platelets.

Blood Platelets↗
PubMed1987

Heterophyle antibodies causing false positive radio-immunoassay results. A case report.

A case report of falsely elevated serum hormone values measured by radio-immunoassay (RIA) is described. The radio-immunoassays concerned have a first antibody raised in rabbits and mostly a separation technique based on a second antibody-solid phase system. The presence of heterophyle (anti-rabbit) antibodies in patients' serum is proved.

Adrenocorticotropic Hormone↗
PubMed1987

Quality control of culture media for in vitro fertilisation.

The organisation of a control programme to evaluate the quality of culture media for human in vitro fertilisation is described. The development of mouse embryos to the blastocyst stage in vitro was used as control system. It is shown that it was possible to screen for embryo toxic chemicals in the media so that these can be avoided in the human culture. The influence of temporary pH shifts on the mouse embryo development and in vitro fertilisation in the mouse are mentioned. Exposure to low pH before fertilisation caused a drastic reduction of the development of mouse embryos. No clear association is found between pregnancy rate using in vitro fertilised human oocytes and mouse embryo development. The control system cannot be used to improve media for human in vitro fertilisation.

Animals↗