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Results for “Fertilization rate”

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PubMed1986

Positive correlation between body weight, length of human menopausal gonadotropin stimulation, and oocyte fertilization rate.

One hundred four normally cycling women were treated with fixed low-dose human menopausal gonadotropin (hMG) (2 ampules/day) in preparation for oocyte aspiration for in vitro fertilization. The response rate was related to age, weight, and the ratios weight/height2 and weight/height. The required dose of hMG was related to total body weight, but not to age or either of the weight/height ratios. In patients who required fewer than 5 days of hMG (rapid responders), a significantly higher number (P less than 0.02) of oocytes were harvested, compared with slow responders. However, a smaller percentage of the oocytes from rapid responders fertilized (P less than 0.003) and resulted in a reduced rate of embryo transfer. The difference in pregnancy rates was not statistically significant. The results of the study suggest that patients undergoing in vitro fertilization who weigh less than 55 kg may benefit from treatment with a lower dose of hMG to prolong the stimulation cycle.

Adult↗
PubMed1992

Investigation of means to improve rates of fertilization in in vitro matured/in vitro fertilized bovine oocytes.

Experiments were conducted with 5,979 oocytes to determine whether detaching some of the cumulus cells from oocytes either before or after maturation would improve the fertilization rate and proportion of oocytes that developed to expanded blastocysts. Oocytes were aspirated from ovaries of slaughtered cows and matured, fertilized and cultured in vitro. Pipetting immature oocytes before maturation to detach some of the cumulus, with all cumulus cells left in the maturation wells, significantly increased fertilization rates, especially of oocytes that initially had a full cumulus investment. In further experiments, pipetting oocytes either before or after maturation to detach most of the cumulus, or treating with hyaluronidase after maturation to disperse the cumulus, significantly increased fertilization rates and proportions of oocytes developing to expanded blastocysts.

Journal Article↗
PubMed1996

The effects of prenatal diagnosis, population ageing, and changing fertility rates on the live birth prevalence of Down syndrome in New York State, 1983-1992.

The incidence of Down syndrome (DS) at conception is highly dependent on the maternal age distribution and age-specific pregnancy rates. The live birth prevalence of DS reflects these factors and fetal deaths. This study examined DS live birth prevalence from 1983 to 1992 in New York State and analysed the effects of demographic changes and prenatal diagnosis use on the observed live birth prevalence. Expected DS live birth prevalence without prenatal diagnosis was calculated and compared with observed. Data were obtained from birth defects registries, vital records, and population data maintained by the New York State Department of Health. Over time, DS live birth prevalence was stable at about 10.4 per 10,000 live births. The percentage and number of women in the population above age 30 increased, as did birth rates among these women. Birth rates among younger women decreased. The proportion of DS babies born to women aged 35 and over increased from 27.1 to 34.1 per cent. Use of prenatal diagnosis by this age group ranged from 39.6 to 43.2 per cent, and increased steadily from 1.8 to 4.3 per cent among women under 35. Detection of DS fetuses increased from 82 in 1985 to 233 in 1992. Without prenatal diagnosis, DS live birth prevalence in 1992 would have reached 15.3 per 10,000 live births compared to the 10.2 observed. Prenatal diagnosis has prevented an increase in DS live birth prevalence but has not been sufficient to reduce live birth prevalence significantly.

Adolescent↗
PubMed2003

In vitro fertilization and polyspermy in the pig: factors affecting fertilization rates and cytoskeletal reorganization of the oocyte.

Polyspermy is a common phenomenon in the pig. Extensive information has become available from in vitro studies on not only the quality of oocytes but also the quality of spermatozoa. However, little information is available on the relative penetration rates of fresh and frozen spermatozoa from the same ejaculate from boars of different breeds. The present results, based on a total of 15 boars of three different breeds, revealed that the inter-breed variation in fertilization and polyspermic rates is larger than intra-breed variation. It was also shown that the incidence of polyspermy as well as penetration rate was greatly decreased by freezing and thawing, even if a higher number of sperm was coincubated with cumulus-free oocytes for a longer period compared to fresh sperm of the same ejaculate. This study focuses on the cytoskeletal organization of the oocyte with respect to the status of cumulus investment, and monospermic and polyspermic fertilization. The status of cumulus cells correlated with the density of transzonal cumulus-cell processes and with the maturation rate of oocytes and, to some degrees, the incidence of polyspermy. Polyspermic zygotes formed multiple microtubule domains in association with individual male pronuclei (PN), but in a high degree of polyspermy (more than trispermy), the pronuclear apposition did not proceed. The effect of multiple PN of paternal and maternal origin on the cytoskeletal reorganization is also discussed.

Animals↗
PubMed1975

Fertility rates and abortion rates: simulations of family limitation.

A computerized model that simulates reproductive events during the childbearing years of a cohort of women is used to analyze the impact of contraception and induced abortion on fertility. Four different reproductive regimens are investigated: (2) contraception only, (2) abortion only, (3) abortion as a backstop to contraception, and (4) combinations of abortion and contraception. It is concluded that in historical as well as in modern populations, levels of fertility near replacement are unlikely to be obtained without the use of induced abortion.

Abortion, Induced↗
PubMed2001

A sensitivity analysis of the Bongaarts-Feeney method for adjusting bias in observed period total fertility rates.

Our sensitivity analysis shows that the adjusted TFR'(t) using the formula of Bongaarts and Feeney (1998), which assumes an invariant shape for the fertility schedule, usually does not differ significantly from an adjusted TFR"(t) that allows the shape of the fertility schedule to change at a constant annual rate. Because annual changes in the shape of the fertility schedules often are approximately constant except in abnormal conditions, the Bongaarts-Feeney (B-F) method is generally robust for producing reasonable estimates of the adjusted TFR'(t). The adjusted TFR'(t) neither represents any real cohort experiences from the past nor forecasts any future trend. It merely provides an improved reading of the period fertility measure, which reduces the tempo distortion.

Analysis of Variance↗
PubMed2000

Percutaneous epididymal sperm aspiration versus microsurgical epididymal sperm aspiration for irreparable obstructive azoospermia--experience with 100 cases.

PURPOSE: This study investigated the sperm retrieval success rates, fertilization rates, pregnancy rates, and complications of percutaneous epididymal sperm aspiration (PESA) and microsurgical epididymal sperm aspiration (MESA) in cases of irreparable obstructive azoospermia. METHODS: During a period of 36 months, 100 men with irreparable obstructive azoospermia underwent 109 cycles of sperm retrieval procedures and intracytoplasmic sperm injection (ICSI). We routinely performed PESA first in each retrieval cycle; MESA and/or testicular sperm extraction (TESE) were performed if PESA failed. The sperm retrieval success rates, mean fertilization rates, and pregnancy rates of PESA and MESA were evaluated. RESULTS: PESA was performed in all 109 retrieval cycles with a successful sperm retrieval rate of 61%. When PESA failed to retrieve a sufficient number of viable sperm, MESA was subsequently performed with a sperm retrieval rate of 93%. Three cases, which had failed retrieval with both the PESA and MESA procedures, received TESE successfully. The rates of fertilization and pregnancy were 56% and 39% in the 66 PESA-ICSI cycles, respectively, and 47% and 45% in the 40 MESA-ICSI cycles. No significant differences were found in fertilization rates or pregnancy rates among the various sperm retrieval methods and obstruction etiologies. The overall mean fertilization rate and pregnancy rate were 51% and 41%, respectively. CONCLUSION: Both PESA and MESA can be used successfully to obtain sufficient sperm for ICSI. PESA cannot replace MESA in some cases as some epididymal pathologies prevent its success. The results of this study indicate that PESA should be the treatment of choice for patients with ductal obstruction distal to the epididymis, owing to its higher initial success rate. In contrast, patients with irreparable epididymal obstruction might achieve better success rates with MESA.

Epididymis↗
PubMed1977

[The decline of fertility in Western Europe. II. Which fertility rate would be desirable in France? (author's transl)].

A way to try and assess the significance of such or such level in long term fertility is to work out population projections based on a variety of assumptions and to compare their different implications. The age pyramids of France until 2100 that derive from four contrasted evolutions of fertility are studied in the present article: completed fertility in birth cohorts ranging from 1.4 to 2.6 children per woman. While some demographic parameters are not much sensitive to the assumption made for the fertility level (e.g. percent of economically active people in total population), others are closely related to fertility (such as total number of inhabitants, percent of younger people or of older people in total population, annual rate of entry into economically active population). In France, where population density is much lower than in most neighbouring countries, a fertility level that would lay at -- or a little higher than -- replacement (i.e. 2.1 children per woman) can be considered as a desirable target.

Adolescent↗