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Gernot Tews

Publications and source records attributed to Gernot Tews.

13 recordsLinked to original sources
PubMed2006

Is oocyte morphology prognostic of embryo developmental potential after ICSI?

Metaphase II-stage oocytes collected from patients following ovarian stimulation show varying qualities. Both nuclear and cytoplasmic maturation have to be completed in a co-ordinated mode to ensure optimal conditions for subsequent fertilization. Disturbances or asynchrony of these processes may result in different morphological abnormalities, depending on whether nuclear or cytoplasmic maturation has been affected. In this respect it has been suggested that dysmorphic features occurring early in meiotic maturation may be associated with a higher frequency of aneuploidy and fertilization failure, while those occurring late in maturation may cause a higher incidence of developmental failure. In fact, more than half of the gametes collected show morphological abnormalities, some of which seem to be correlated with an impaired outcome (e.g. aggregation of endoplasmic reticulum, vacuolization, increased ooplasmic viscosity, giant eggs). Therefore, it is strongly recommended to include oocyte quality in all scoring systems applied in IVF laboratories.

Embryonic Development↗
PubMed2005

Cytoplasmic pitting has a negative influence on implantation outcome.

PURPOSE: Since cytoplasmic pitting is a morphological phenomenon discussed controversially, this study was set up in order to assess the actual influence of cytoplasmic pitting on treatment outcome. METHODS: Four hundred and one patients undergoing 484 consecutive treatment cycles were evaluated retrospectively in order to assess the actual influence of pitting on treatment outcome. RESULTS: Pitting was found to be reduced in single culture as compared to group culture (p < 0.01). No correlation of cytoplasmic texture with rates of implantation and pregnancy could be observed, but a significantly higher proportion (p < 0.05) of gestational sacs vanished in the group with exclusive transfer of pitted embryos compared to the unaffected group. Obstetric and perinatal outcome was not affected. CONCLUSIONS: It is possible that culture conditions favor cytoplasmic pitting, a morphological phenomenon which, in the extreme case, may result in early loss of gestation sacs.

Adult↗
PubMed2005

Occurrence and developmental consequences of vacuoles throughout preimplantation development.

OBJECTIVE: Since little is known about the actual incidence and fate of vacuoles at different stages of development this preliminary study was set up to accurately measure vacuoles and track them to day 5. DESIGN: Prospective study. SETTING: Women's General Hospital in Austria. PATIENT(S): A total of 223 consecutive IVF and intracytoplasmic sperm injection (ICSI) cycles (206 patients). INTERVENTION(S): Accurate measurement of vacuoles. Affected gametes and embryos were cultured individually and tracked until day 5. MAIN OUTCOME MEASURE(S): Size and number of vacuoles, fertilization rate, blastocyst formation rate, blastocyst quality. RESULT(S): There was a significant relationship between size of the vacuole (cut-off value 14 microm) and fertilization (P<.05). At zygote stage the incidence of vacuoles was higher (P<.01) in ICSI (11.6%) than in IVF (5.3%). Only 32.2% of affected ICSI-embryos reached blastocyst stage on day 5 compared with 53.0% of the normal ones (P<.001). In terms of blastocyst formation vacuolization on day 4 (P<.001) turned out to be the most severe one. At blastocyst stage inner cell mass was affected less frequently than the trophectoderm (P<.05). CONCLUSION(S): Three types of vacuoles could be identified: (1) those already present at oocyte collection, which develop during maturation (day 0); (2) those artificially created by ICSI (day 1); and (3) those accompanied with developmental arrest (day 4). The later that vacuoles arose, the more detrimental their effect on blastocyst formation.

Blastocyst↗
PubMed2005

Predictive value of cumulus cell apoptosis with regard to blastocyst development of corresponding gametes.

OBJECTIVE: To test if a high degree of apoptosis in cumulus cells could indicate diminished oocyte quality and developmental competence. DESIGN: Prospective analysis. SETTING: Public hospital and university. PATIENT(S): Thirty seven women who gave written consent to participate in this study. INTERVENTION(S): Cumulus-oocyte complexes were denuded separately and the resulting cumulus cell suspensions were analyzed for presence of apoptosis using a terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay detection kit. MAIN OUTCOME MEASURE(S): Percentage of apoptotic cumulus cells and blastocyst formation rate. RESULT(S): Younger patients (< or = 35 years) showed significantly fewer apoptotic cumulus cells than older ones. In all patients gamete maturity was shown to be highly correlated to the rate of apoptosis in cumulus cells. At zygote and cleavage stages (days 1 to 4) no morphologic features were related to the degree of programmed cell death. However, blastocyst development was predictable taking into account the percentage of apoptosis in associated somatic cells. In addition, there was a trend toward better quality blastocysts from follicles with a lower rate of apoptotic cells. No influence on pregnancy and implantation rate was observed. CONCLUSION(S): Apoptotic processes within follicles seem to impair oocyte maturation. Though not manifested in the morphologic appearance, gametes and embryos derived from cumulus complexes with no or minor apoptosis have an increased chance of giving rise to optimal blastocysts.

Adult↗
PubMed2005

Assisted vaginal delivery versus caesarean section in breech presentation.

BACKGROUND: The Term Breech Trial (TBT), a well-known study conducted by Hannah and published in the Lancet, revealed a better outcome for neonates after primary caesarean section compared with attempted vaginal delivery. The aim of the present study was to determine whether the results of TBT have to be taken into account when counseling pregnant women in central Europe. METHODS: We investigated 882 women who had delivered infants in breech presentation over a period of 11 years. The neonates had a birthweight of >2500 g and no malformations. We compared mortality and serious neonatal morbidity after attempted vaginal delivery and after primary caesarean section. RESULTS: No infant or maternal mortality was registered in either group. Serious neonatal morbidity was higher (0.5%; n = 2) for attempted vaginal delivery than for primary caesarean section; in the latter group, no child fulfilled the criteria for serious neonatal morbidity. However, the difference was not statistically significant. As expected, after attempted vaginal delivery, the base excess, and 5-min APGAR scores were indicative of more markedly depressed children. CONCLUSION: After careful exclusion of risk factors and informing the patient in detail about the risks and possible complications, vaginal delivery from breech presentation is still warrantable.

Adult↗
PubMed2004

Premature rupture of membranes with oligo- or anhydramnios before 24 weeks of gestation and the chances of fetal survival.

UNLABELLED: Rupture of the membranes before the fetus has achieved viability within the womb is an event of enormous importance for both mother and physician. The potential outcome ranges from fetal death, a frequent occurrence, to a severely disabled life or a happy (but rare) birth without any mental or physical retardation for the child. The aim of the present investigation was to provide the consulting physician with valid data, enabling him/her to make a realistic assessment of the risks and to inform the patient accordingly. METHOD: In a retrospective analysis, we followed 36 cases with spontaneous rupture of the maternal membranes and development of oligo-/anhydramnios before 24 weeks of gestation. The patients had been treated between January 1994 and 2004. In a more detailed assessment, the patient cohort was divided into one group of women with rupture between 10 and 20 weeks of gestation and another group with a gestational age between start of week 21 and end of week 23. RESULTS: Of the 36 children, seven (19.4%) survived initially, with two of the seven survivors dying subsequently. Among women with amniorrhexis before week 21 of gestation, only three of the 26 children survived, while four of 10 children survived among women with premature rupture of membranes between 21 and 23 weeks of gestation (p = 0.053) No case of mental retardation could be observed in the surviving children. Perinatal outcome was found to be significantly different in the presence of amnionitis (3/27) compared to the group without this event (4/9) (p = 0.028). CONCLUSIONS: Because of the poor fetal outcome, termination of an ongoing pregnancy must also be considered in counseling the mother. If the mother decides to continue her pregnancy, amnionitis will be the most critical factor for ultimate termination of pregnancy.

Austria↗
PubMed2002

Successful birth after laser assisted immobilization of spermatozoa before intracytoplasmic injection.

OBJECTIVE: To describe the first ICSI pregnancy achieved with sperm that were immobilized by using a noncontact diode laser. DESIGN: Case report. SETTING: Fertility center. PATIENT(S): A 36-year-old woman who had had primary infertility for 9 years. INTERVENTION(S): Sperm immobilization by using a 1.48-microm wavelength diode laser and subsequent ICSI. MAIN OUTCOME MEASURE(S): Fertilization and cleavage rates and pregnancy. RESULT(S): Transfer of two embryos with minor fragmentation led to a single pregnancy. The patient delivered a healthy baby in week 38 of gestation. CONCLUSION(S): Use of a noncontact diode laser for sperm immobilization may be a useful alternative to the conventional mechanical approach.

Adult↗
PubMed2002

The potential of preoperative beta-hCG and progesterone levels to predict failure of laparoscopic linear salpingostomy in ectopic pregnancies.

STUDY OBJECTIVE: To estimate the association between preoperative beta-human chorionic gonadotropin (hCG) and progesterone levels, and success of linear salpingostomy in treatment of tubal pregnancy. DESIGN: Retrospective case control study (Canadian Task Force classification II-1). SETTING: Women's general hospital. PATIENTS: Three hundred five women undergoing laparoscopic linear salpingostomy for ectopic pregnancy. INTERVENTION: Examination of risk factors for surgical failure of salpingostomy by analyzing corresponding receiver operating curves. MEASUREMENTS AND MAIN RESULTS: In 305 women, intervention was successful in 272 and failed in 33, as assessed by either postoperative hemorrhage (16) or rising beta-hCG values (14); 3 women had both. Of 295 patients in whom beta-hCG was evaluated preoperatively, 149 (50.5%) had values of 1000 mU/ml. or less; 75% had progesterone levels of 10 ng/ml or below. No association was found between preoperative beta-hCG and progesterone levels and the success of linear salpingostomy. CONCLUSION: Preoperative beta-hCG and progesterone levels are of no significance with regard to success of linear salpingostomy for treatment of tubal pregnancy.

Adult↗