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PubMed1996

The age-related decline in female fecundity: a quantitative controlled study of implanting capacity and survival of individual embryos after in vitro fertilization.

OBJECTIVE: To determine strictly comparable rates per embryo of implantation and birth of a baby related to the woman's age, which would be representative of natural fertility at least in relative terms. DESIGN: Comparative study of IVF-ET results controlling for confounding variables including cause and duration of infertility, history of previous pregnancy, hormonal treatment, rank cycle of treatment, and numbers of embryos transferred and available. SETTING: University comprehensive fertility service. PATIENTS: All couples (n = 561) in their first cycle of treatment reaching oocyte collection, women with normal uterus and ovulatory cycles, and men with normal sperm. INTERVENTIONS: Standardized methods of pituitary desensitization, ovarian stimulation, and IVF-ET, and maximum of three embryos transferred. MAIN OUTCOME MEASURES: Oocytes, pregnancies, and live births per cycle; fertilization and cleavage rates; embryo implantation and live baby rates. RESULTS: The numbers of oocytes and consequent embryos declined with age but fertilization and cleavage rates rose slightly. Embryo implantation rates were reduced when no more than three embryos were available (9.3 percent), especially in women aged 35 to 39 years (6.2 percent) or older compared with four or more embryos (17.1 percent) but were equally low in all women over 40 years even with more embryos (6.1 percent). In the age bands 25 to 29, 30 to 34, 35 to 39, and 40 to 44 years, the rates per embryo of implantation were 18.2 percent, 16.1 percent, 15.3 percent, and 6.1 percent, respectively, and of a live baby were 15.7 percent, 12.1 percent, 12.0 percent, and 3.5 percent. CONCLUSIONS: Embryo implanting ability and survival decline gradually after 30 years of age, but by more than two thirds after 40 years and in younger women with reduced ovarian capacity.

Adult↗
PubMed1988

Improved cryopreserved semen fecundability in an alternating fresh-frozen artificial insemination program.

This study with glycerol and increased number of motile sperm inseminated showed an increase in f to 10.4% for frozen semen and 27.4% for fresh semen. There is a significant (P less than 0.01) difference in pregnancy rate when greater than 100 million motile sperm are inseminated (31.3%) than when less than that number are inseminated (11.9%) in the first cycle when frozen semen is used.

Female↗
PubMed1997

Age at natural menopause in a population-based screening cohort: the role of menarche, fecundity, and lifestyle factors.

OBJECTIVE: To verify whether a population-based hypothesis (age at menarche and age at natural menopause have an inverse relationship) also applies at the level of the individual and to investigate what other factors predict age at natural menopause. DESIGN: Prospective cohort study (the Doorlopend Onderzoek Morbiditeit/Mortaliteit [DOM] project). SETTING: Prevention Breast Cancer Screening Centre, Utrecht, The Netherlands. PATIENT(S): A cohort of 3,756 Dutch women, born between 1911 and 1925, participating in a population-based breast cancer screening program, who experienced a natural menopause. Three samples of women were studied: a sample who did not use oral contraceptives (OCs) (n = 3,347), a sample of OC users (n = 409), and a combined sample of OC users and nonusers (n = 3,756). MAIN OUTCOME MEASURE(S): Age at menopause and menarche, fertility patterns, OC use, height, weight, smoking, and demographic variables. RESULT(S): No relation was found between age at menarche and age at natural menopause. The total percentage of variance in age at natural menopause explained by multiple regression including all factors was minimal, ranging from 1.3% to 9.7% in OC users. Linear regression analysis indicated a slight secular trend in age at menopause. CONCLUSION(S): Frisch's hypothesis could not be corroborated at the individual level. These results suggest that age at menarche and menopause should be treated as independent risk factors for breast cancer. Modification of age at menopause by lifestyle factors (except possibly for OC use) appears minimal.

Age Factors↗
PubMed1998

Ovarian fecundity in patients with endometriosis can be estimated by the incidence of apoptotic bodies.

OBJECTIVE: To investigate the incidence of apoptotic bodies in membrana granulosa in patients with endometriosis. DESIGN: Retrospective analysis. SETTING: Yamagata University Hospital. PATIENT(S): Fifty-eight normoovulatory women with endometriosis and 45 patients with male factor infertility underwent ovulation induction for IVF-ET with GnRH analogues and gonadotropins. INTERVENTION(S): Patients underwent follicle aspiration after the administration of hCG. MAIN OUTCOME MEASURE(S): Recovered granulosa cells (GCs) were examined by fluorescence microscopy, and the incidence of apoptotic bodies was tabulated. These data and the other parameters associated with IVF results were analyzed on the basis of both the revised American Fertility Society (AFS) classification of endometriosis and the existence of chocolate cysts. RESULT(S): The incidence of apoptotic bodies in membrana granulosa of patients with endometriosis was significantly higher than that of the control (male factor infertility) group and increased as the stage of the revised AFS classification advanced. The incidence of apoptotic bodies in membrana granulosa was significantly higher in patients with chocolate cysts than in those without chocolate cysts. The patients with endometriosis had smaller numbers of developed follicles (> or = 15 mm), harvested oocytes, and mature oocytes than the male factor infertility patients. The existence of chocolate cysts corresponded with a reduced number of both harvested oocytes and mature oocytes. CONCLUSION(S): Through the apoptosis of GCs, the existence of endometriosis may have negatively affected the follicle development and oocyte quality.

Adult↗
PubMed1997

Immunization of mice with ultraviolet-attenuated cercariae of Schistosoma mansoni transiently reduces the fecundity of challenge worms.

In the present study cohorts of ICR and BALB/c mice were immunized with u.v.-irradiated cercariae of S. mansoni and challenged 5 weeks later, in parallel with unimmunized control mice, with approximately 100 cercariae. Total worm burdens at 5, 6, 7 and 8 weeks after challenge were significantly reduced by 27-65% in immunized mice. The total number of eggs and the number of eggs/female worm trapped in liver and small intestine were reduced significantly at 6 and 7 weeks post challenge in immunized, as compared to unimmunized mice. Decrease in tissue egg load could be achieved in BALB/c mice passively transferred with spleen cells from u.v.-attenuated cercaria-immunized mice. The proportion of female worms laying eggs in vitro was diminished only in worms recovered from highly resistant mice. The reduction in worm oviposition in immunized mice was no longer apparent at 8 weeks. The data taken together indicate that highly effective immunization of outbred and inbred mice with attenuated cercariae leads to significant, but transient, impairment in challenge worm egg production.

Adoptive Transfer↗
PubMed2000

Feeding, growth, and fecundity of Abarenicola pacifica in relation to sediment organic concentration.

For marine deposit-feeding invertebrates, the distribution of species with different life history strategies has long been known to be correlated with sediment organic concentration. Large populations of opportunistic species are found in sediments with enriched organic concentration, while equilibrium species populate low organic concentration sediments. Differences in both behavioral (e.g. feeding rate) and physiological (e.g. growth rate, reproductive output) adaptations determine the ability of species to establish populations in different environments. By systematically documenting differences in the way these factors vary as sediment organic concentration varies for both opportunistic and equilibrium species, we can better understand the mechanisms underlying this correlation between sediment organic concentration and species distributions. Here, we present the results of experiments examining the interactions among food concentration, feeding rate, growth rate, and reproductive output (measured as egg number and size) for the equilibrium species Abarenicola pacifica. A. pacifica is a large, long-lived, iteroparous, sub-surface deposit-feeding polychaete. Individual worms were reared throughout most of one generation in sediments differing only in the concentration of organic matter. Juveniles (<20 mg AFDW) had higher feeding rates and growth rates in sediments of higher organic concentration throughout the range tested. These results are consistent with the predictions from optimal foraging theory. As worms grew, however, these patterns changed. Once worms reached a mean body size of approximately 50 mg AFDW, feeding rate was greater on sediments of lower organic concentration (although it took worms in the sediments with lower organic concentration longer to reach this size). Differences in growth rates among treatments decreased as worms grew. For worms >100 mg AFDW, growth rates were uniformly low ( approximately 1%/day) on all sediments, but the early advantage obtained by worms in the high organic treatments resulted in much greater body sizes after 200 days. Worms had higher tissue triacylglyceride concentrations and produced more eggs (independent of worm size) as sediment organic concentration increased. We conclude that A. pacifica alters its feeding rate in response to variations in food resources in such a way as to maximize its energy intake and thereby maximize fitness. Future studies should investigate whether opportunistic species (as well as other equilibrium species) also have this ability.

Journal Article↗
PubMed1996

Effect of sub-lethal doses of albendazole on the fecundity of Dictyocaulus viviparus.

During an evaluation of the efficacy of prolonged low-dose albendazole therapy on nematode infections in calves, it was observed that a dose-rate of 2 mg kg-1 given daily for 10 days was highly effective at expelling Dictyocaulus viviparus, but smaller doses suppressed the faecal output of larvae without killing the lungworms. A more detailed study with four experimentally infected calves given 1 mg kg-1 day-1 for 10 days showed that faecal output of larvae ceased after six to eight days but resumed four to six days after the withdrawal of the drug. The albendazole-induced sterility was therefore reversible. A subsidiary study showed that the strain of parasite used was fully susceptible to albendazole.

Albendazole↗
PubMed2003

Effects of hCG on folliculogenesis and fecundity in mink (Mustela vision Schreb).

The endogenous hormonal response obtained after reproductive organs are challenged by exogenous hormones is increasingly being used to predict presence of functional reserves and to apply this information to improve efficiency of managed breeding programs. With that in mind, the aim of the present study was to investigate the effect of a single treatment with hCG on folliculogenesis and fertility in standard 7-month-old mink females. The extent of stimulation following treatment was determined by examining patterns of vaginal smears. Characteristics of each cycle stage were: estrus, preponderance of cornified epithelial cells; proestrus, polygonal, elongate epithelial cells; anestrus, parabasal, intermediate and leucocyte cells. Smears exhibiting a mixed population of cells were categorized as being in transition between adjacent stages anestrus-proestrus or proestrus-estrus. The initial evaluations were done on Day 6 after hCG treatment. Histomorphometric examination of ovaries and uteri was done during seasonal anestrus (November) and in the breeding season (March). Vaginal cytology patterns were correlated with changes in folliculogenesis. A mean of 1.3 mature (Graafian) follicles were counted during estrus, while the mean number seen during anestrus, anestrus-proestrus and proestrus, were 0.4, 0.3 and 1.0, respectively. During the breeding season, in females that were not treated, the numbers of growing follicles decreased and maturing follicles increased, whereas females that came in estrus after treatment with hCG in November had increased numbers of both growing and maturing follicles. Fertility after breeding in hCG-treated females was increased by 9.2% (P<0.05) as compared to untreated females. Females showing the highest fertility rise (27%) were predominantly in the group that showed estrus after hCG treatment. We conclude that monitoring the response of the mink reproductive system to hCG stimulation in November may be a useful tool for identifying females of high fertility in the spring.

Animals↗
PubMed2000

Geographical variation in Ascaris lumbricoides fecundity and its implications for helminth control.

The observation by microscopy of nematode eggs in human faeces is used to diagnose a helminthic infection, while the concentration of those eggs is used to estimate the number of worms in the host. Within a community, the prevalence of infection and the mean egg count provide useful information about the extent of a public health problem, and are being used to guide the growing efforts to control disease caused by helminths. Here, Andrew Hall and Celia Holland examine data on the relationship between the worm burdens of Ascaris lumbricoides and the concentration of eggs in faeces, and discuss the implications of the variation found for using such data to plan helminth control programmes.

Adolescent↗
PubMed2004

Smoking and female fecundity: the effect and importance of study design.

This review evaluates the evidence for a link between smoking and female fertility. Twenty-two primary papers and two reviews were found. All but three indicated a detrimental effect of smoking on reproduction despite varying considerably in their approach, definitions used and populations studied. The strength of association is small but statistically significant and a dose response relationship suggests the theory that smoking is causative. Poor design in particular and the failure to assess confounders weakened many studies and should be addressed in future studies.

Adolescent↗
PubMed2000

The role of luteal steroid hormones in the regulation of the estrous cycle of high fecundity Olkuska sheep.

The study was undertaken to investigate the steroid hormone production by sheep luteal cells. Corpora lutea were collected from 30 Olkuska sheep on Days 3, 6, 9, 12 and 15 of the estrous cycle during the reproductive season. In Experiment 1, steroid hormone concentration was estimated in extracts of CL. In Experiment 2, luteal cells were cultured in vitro for 24 h. Luteal cells isolated on Days 9 and 12 secreted high amounts of progesterone and androgens but smaller amounts of estradiol. Concentration of these steroids in CL extracts collected on the same days showed the same trend. In CL harvested on Day 15, a decrease in androgens and progesterone as well as a significant increase in estradiol were observed in culture media and in extracts. Judging from the high amounts of estradiol and low amounts of androgen observed at the end of the luteal phase, we speculate that the steroid hormones secreted by the regressing CL may play an active role in the regulation of the estrous cycle in the Olkuska sheep with autocrine influence on the luteal activity or a possible paracrine action on follicular growth. In the third Experiment, the possibility of heterogeneity in the multiple corpora lutea population of prolific Olkuska sheep was investigated. Differences were found in the level of progesterone and estradiol secretion by individual corpora lutea recovered from the same animal, which also varied in terms of weight. This is the first study which shows the existence of intra-ovarian and individual heterogeneity between corpora lutea recovered from ewes during the normal estrous cycle.

Androgens↗
PubMed2003

ACE inhibitors reduce fecundity in the mosquito, Anopheles stephensi.

Angiotensin-converting enzyme (ACE) is a dipeptidyl carboxypeptidase, which cleaves dipeptides and, in some instances, dipeptide or tripeptide amides from the C-terminus of regulatory peptides (e.g. angiotensin I, bradykinin and substance P). The expression of ACE is highly regulated in insects, where it is thought to have a role in the metabolism of peptide hormones involved in regulating reproduction. After a blood meal, ACE activity in the female mosquito Anopheles stephensi, increases four-fold with much of the enzyme finally accumulating in the ovary. In the present study, we have studied the effect on reproduction of adding two selective inhibitors of ACE, captopril and lisinopril, to the blood meal. Both ACE inhibitors reduced the size of the batch of eggs laid by females in a dose-dependent manner, with no observable effects on the behaviour of the adult insect. The almost total failure to lay eggs after feeding on either 1 mM captopril or 1 mM lisinopril, did not result from interference with the development of the primary follicle, but was due to the inhibition of egg-laying. Since very similar effects on the size of the egg-batch were observed with two selective ACE inhibitors, belonging to different chemical classes, we suggest that these effects are mediated by the selective inhibition of the induced mosquito ACE, a peptidase probably involved in the activation/inactivation of a peptide regulating egg-laying activity in A. stephensi.

Angiotensin-Converting Enzyme Inhibitors↗