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PubMed1992

Relationship of follicle number and other factors to fecundability and multiple pregnancy in clomiphene citrate-induced intrauterine insemination cycles.

OBJECTIVE: To determine characteristics associated with pregnancy and multiple gestation after clomiphene citrate (CC)-intrauterine insemination (IUI). DESIGN: Prospective study of all patients undergoing CC-IUI between January 1, 1983 and December 31, 1989. SETTING: Private fertility clinic. PATIENTS: Eight hundred forty-nine patients undergoing 1,974 cycles of CC-IUI. MAIN OUTCOME MEASURES: Relationship between number and size of preovulatory follicles, age, additional infertility diagnosis, medication, and initial semen quality to fecundity, birth, and multiple gestation. RESULTS: Uncorrected, per cycle fecundity was 7.2%. The number of follicles greater than or equal to 12 mm (r = 0.055, P less than 0.05) was and the number greater than or equal to 15, 18, and 21 mm was not correlated with fecundity. Endometriosis with (P = 0.013) or without (P less than 0.0005) tubal adhesions and tubal adhesions alone (P = 0.005), decreased fecundability by 50%. Initial semen quality did not affect fecundity, unless semen concentration was less than 5 x 10(6)/mL or motility was less than 20%. Multiple pregnancy was not associated with the dose of CC, use of human chorionic gonadotropin, or number of follicles. CONCLUSIONS: Multiple pregnancy was unrelated to follicle numbers or to CC dose. The highest birth rates after CC-IUI occurred when initial sperm concentration was greater than or equal to 5 x 10(6)/mL, motility was greater than or equal to 20%, and no endometriosis or adhesions were present.

Clomiphene↗
PubMed1991

The effect of age on female fecundity.

To determine the relationship between age and female fecundity, 210 women were studied prospectively. The subjects had negative infertility evaluations and were receiving therapeutic donor insemination. Life-table analysis was performed on 751 donor insemination cycles. For comparison, patients were divided into five separate age groups and into two separate groups, ages 19-34 and 35-45. Monthly fecundity and cumulative conception rates were calculated for each group. A significant difference was found when all age groups were compared (P = .05) and when those at or above age 35 and those below age 35 were compared (P less than .05). Frozen semen was used in 92% of all cycles. The average monthly fecundity of all patients treated with frozen semen was 16%. This study confirms a progressive decline in fecundity with age in a completely evaluated group of women undergoing therapeutic donor insemination and demonstrates that frozen semen can yield acceptable fecundity provided sufficient numbers of motile sperm are used for each procedure.

Adult↗
PubMed1978

Effects of various factors on selection for family planning status and natural fecundability: a simulation study.

The effect of various factors on selection for family planning status and for natural fecundability is studied in a simulation that incorporates a beta distribution of fecundability among women. The mean fecundabilities of current spacers, current limiters, current nonusers, and pregnant women are compared. These ratios are influenced by duration of marriage and by desired number of children. Effects of different levels of contraception are measured. Another strategy, spacing the last two wanted births, is also studied. It is found that breast-feeding status has little effect on fecundability selection. The women usually found to have greatest fecundability are not those recently pregnant at durations of marriage five and ten years, unless they wanted fewer than two children, but rather those who are using contraception to limit the number of children.

Adult↗
PubMed1984

The effect of experimental Onchocerca infections on the fecundity and oviposition of laboratory reared Simulium sp. (Diptera, Simuliidae).

Two species of Simulium were used to examine the effect of experimental Onchocerca lienalis infections on their fecundity and oviposition rates. S. ornatum s.l. was chosen as a natural vector of bovine onchocerciasis in Britain, and S. lineatum was selected because of its suitability as an experimental model for oviposition studies. Infection was either by feeding with blood containing microfilariae, or by intrathoracic injection of the parasites. Using the blood feeding technique, reductions in the fecundity of S. lineatum were observed at rates of 21 to 76%, depending on the concentration of parasites. A reduction of 21% in the fecundity of S. ornatum s.l. (P less than 0.05) was achieved when flies were fed on microfilariae at 69,000 per ml. Although individual flies feeding on infected blood may take as much as those in control groups, the feeding rates were reduced in several instances. S. lineatum also showed a depression of oviposition rate when infected by O. linenalis larvae. Fecundity was also significantly reduced when the route of infection was intrathoracic. Reductions for S. lineatum depended on the inoculum, but were either 36% (10 microfilariae per fly) or 54% (50 microfilariae per fly). S. ornatum s.l. showed a 13% reduction in fecundity when given 20 microfilariae per fly. It was concluded that similar experimental studies could be usefully performed with S. damnosum s.l. infected with O. volvulus microfilariae.

Animals↗
PubMed1982

The effects of cortisone on fecundity, number, and distribution of adult Trichinella spiralis and on trichinous enteritis in the host.

The effects of cortisone on fecundity, distribution, and numbers of adult Trichinella spiralis and on enteritis in the host were compared in mice receiving different numbers of larvae. As the amount of cortisone given to mice was increased enteritis decreased, and fecundity of adult worms increased. Injection of mice with cortisone caused retention of a greater percentage of adult worms in the anterior regions of the host small bowel than in uninjected mice. By day 11 PI, when adult worms in cortisone-injected mice were more widely distributed along the host small intestine, fecundity of adult worms isolated from mice receiving more worms (500, 1,000, or 2,000 worms) attained levels previously seen only in worms from mice infected with 250 T. spiralis. The extended longevity of adult worms in cortisone-injected mice was accompanied by a severe reduction in fecundity after day 11 PI. Addition of cortisone to the culture medium at concentrations above 0.1 mg% was accompanied by a reduction in fecundity of adult worms.

Animals↗
PubMedDate not supplied

Puberty and the family formation process in Sudan: age-at-menarche differential fecundity hypothesis revisited.

This paper revisits and extends an inquiry on the age-at-menarche differential fecundity hypothesis. Earlier studies have interpreted the difference in the onset of female pubertal maturation as indicative of biological differences in fecundity between early and late menarcheal women. Using the WFS data for Sudan, the authors address the entire reproductive life of the women in terms of their transition from one parity to the next, as well as the speed with which birth intervals are closed, as a way to infer biological fecundity among the women. The study concludes that there is little evidence that early menarcheal women are more fecund than their late puberty counterparts.

Adult↗
PubMed1993

Relationship of endometrial thickness and pattern to fecundity in ovulation induction cycles: effect of clomiphene citrate alone and with human menopausal gonadotropin.

OBJECTIVE: To determine if preovulation endometrial thickness or pattern are related to fecundity and to use of clomiphene citrate (CC) or hMG in IUI. DESIGN: Prospective ultrasound evaluation the day of hCG after CC alone (n = 197), hMG alone (n = 49), concurrent hMG or sequential CC and hMG (n = 205), and no medications (n = 23). SETTING: Private fertility clinic. PATIENTS: Two hundred seventy-one patients undergoing 474 cycles of IUI. MAIN OUTCOME MEASURES: Endometrial thickness, pattern, per cycle fecundity, and continuing pregnancy. RESULTS: Endometrial thickness was related to fecundity and continuing pregnancy. No pregnancies occurred when thickness was < 6 mm. The continuing pregnancy rate was 12.6% when thickness was > or = 9 mm, compared with 6.9% when thickness was 6 mm to 8 mm. Endometrial pattern was unrelated to pregnancy. Average endometrial thickness was decreased when hMG and CC were used in combination (7.9 mm) compared with hMG alone (9.4 mm). Endometrial thickness was negatively related to CC dose and positively related to the day of hCG administration by ANOVA. CONCLUSIONS: Endometrial thickness the day of hCG administration is prognostic of fecundity and continuing pregnancy in cycles of ovulation induction.

Adult↗
PubMed1996

Does cigarette smoking impair natural or assisted fecundity?

OBJECTIVES: To assess the effects of female and male smoking on natural and assisted fecundity. DESIGN: A systematic review of published studies was conducted, identifying reports using on-line and hand search techniques. INCLUDED STUDIES: Potentially relevant articles were screened for inclusion based on the following criteria: comparative study (cohort or case control) with clinical pregnancy or live birth reported among smokers and nonsmokers. EXPOSURE: Cigarette smoking. MAIN OUTCOME MEASURES: Time to conceive; conceptions per subject or per cycle; spontaneous abortion rate. RESULTS: Thirteen relevant studies of natural conception were identified. All but one demonstrated a negative association between smoking and fecundity (odds ratio [OR] for conception or live birth 0.33 to 1.0). Seven studies of IVF-GIFT yielded a common odds ratio for conception of 0.57 (95% confidence interval 0.42 to 0.78). Seven studies evaluating spontaneous abortion suggested a small increased risk among female smokers (OR 0.83 to 1.8). Twenty-one studies assessing smoking in men demonstrated no consistent effect on sperm quality. None of the four studies evaluating fertility in male smokers demonstrated significant impairment. CONCLUSION: This body of literature suggests a small but clinically significant detrimental effect of female smoking on both time to conception and spontaneous abortion risk. Variability between studies, particularly in terms of adjustment for confounding factors, undermines the strength of these conclusions. However, the consistent dose-response effect in both the spontaneous conception and abortion literature and a return to normal fecundity among exsmokers suggest a causal association. The effect of male smoking on fecundity is probably far less significant.

Abortion, Spontaneous↗
PubMed1997

Schistosoma mansoni oviposition in vitro reflects worm fecundity in vivo: individual-, parasite age- and host-dependent variations.

In an attempt to determine whether in vitro oviposition of adult S. mansoni reflects the fecundity status of worms in vivo, Mongolian gerbils and ICR, BALB/c and SCID mice were infected with about 100 cercariae and examined on an individual basis, 5-12 weeks later, for worm burden, counts of eggs in liver and small intestine, and for the rate of egg deposition of ex-vivo female worms cultured in vitro, singly or in pairs, over a 3-5 day incubation period. The percentage of egg-laying female worms and the number of eggs laid/female after 3 days in culture showed, like worm fecundity in vivo, wide inter-worm variability, especially in 5-, 6- and 12-week-old worms; varied significantly with the age of the parasite with a maximum level attained by worms of approximately 8 weeks of age; and differed in worms recovered from different host species and strains. The data taken together indicate that measuring the egg-producing ability of S. mansoni in vitro reflects the fecundity status of worms in vivo and additionally provides likely explanations for hitherto poorly understood findings on schistosome fecundity.

Animals↗
PubMed1997

Fecundity of sealworm (Pseudoterranova decipiens) infecting grey seals (Halichoerus grypus) in the Gulf of St. Lawrence, Canada: lack of density-dependent effects.

Uterine egg counts were determined by means of an electronic particle counter in individual female sealworm, Pseudoterranova decipiens (Nematoda: Ascaridoidea: Anisakidae) collected from grey seals (Halichoerus grypus) from Anticosti Island, northern Gulf of St. Lawrence, in August and September 1992. Mean number of eggs per female was 54,916.9 (+/- 51,866.4), with a maximum of 300,000. Egg counts were strongly correlated with worm length, and less so with host sex and age, sealworm sex ratio, and densities of Anisakis simplex and Phocascaris sp. No effect of sealworm density on worm egg counts was determined and competitive effects by Contracaecum osculatum on sealworm fecundity were not observed. Analyses demonstrated that variation in sealworm fecundity was greater among seal hosts within groups than between groups for host age and sex, density of sealworm, and density of C. osculatum. No evidence for density-dependent regulation of sealworm fecundity could be found. Variations in worm egg counts are attributed to individual host effects on worm growth and fecundity.

Animals↗
PubMed1997

Anti-fecundity immunity to Schistosoma japonicum induced in Chinese water buffaloes (Bos buffelus) after vaccination with recombinant 26 kDa glutathione-S-transferase (reSjc26GST).

We have shown previously that immunisation of mice and pigs with recombinant 26 kDa GST (reSjc26GST) induces a pronounced anti-fecundity effect after experimental infection with Chinese Schistosoma japonicum. We report here that anti-fecundity immunity can also be induced against reSjc26GST in Chinese water buffaloes (Bos buffelus), important reservoir hosts for S. japonicum in China. Anti-Sjc26GST antibodies were produced in immunised buffaloes and, following challenge with S. japonicum cercariae, a 22.3% reduction in worm numbers was evident in vaccinated when compared with control animals. The anti-fecundity effect was characterised by a significant decrease in faecal egg output and eggs deposited in host tissues with those in the liver and intestine being reduced by about 50%. In addition to the anti-fecundity effect, reSjc26GST reduced by nearly 40% the egg-hatching capacity of S. japonicum eggs into viable miracidia. In terms of vaccination strategy, these effects would combine to diminish pathology in animals immunised with reSjc26GST and reduce transmission of schistosomiasis japonica.

Animals↗
PubMed1984

Fecundity-reducing pheromone in Argas (Persicargas) arboreus (Ixodoidea: Argasidae).

Fed adult Argas (Persicargas) arboreus produce a fecundity-reducing pheromone which affects all or most females in crowded conditions. Unfed adults and unfed and fed nymphs do not produce this pheromone. The effect of this pheromone is probably additive, increasing with additional crowding of adults. Mechanical disturbance is excluded as the cause of fecundity reduction. Fed females separated by a perforated barrier from crowded adults also exhibit very low fecundity. Adult excretory materials used 31 days post-feeding do not contain the fecundity-reducing pheromone. Preliminary experiments suggest that this pheromone is spatially limited in action, does not affect gonadotropic hormone synthesis and/or release, and does not induce oviposition deterrence behaviour. This may be considered to be a primer pheromone, causing alteration in normal vitellogenin synthesis and/or uptake and deposition in oocytes. The source and chemical nature of this pheromone should be investigated.

Animals↗
PubMed1986

Experimental infection of Tribolium confusum (Coleoptera) by Hymenolepis diminuta (Cestoda): host fecundity during infection.

Some effects of Hymenolepis diminuta on the fecundity of Tribolium confusum are described. Host fecundity is observed to be reduced exponentially with increasing parasite burden/host, although there are differences in the ability of individual hosts to respond to parasitism. Of particular interest is the finding that host fecundity is greatly reduced in young beetles on or by day 14 post-infection (p.i.). This age-related reduction in host fecundity is discussed in relation to the population dynamics of this host-parasite relationship.

Aging↗
PubMed2002

Fecundity and life span in transgenic Drosophila melanogaster overexpressing hsp70.

In the present study, we investigated the effect of hsp70 overexpression on some life history components in transgenic fruit flies. We measured life span in mated flies and fecundity in flies subjected or not subjected to a heat shock inducing hsp70. Heat shock increased life span of the parental line, but not of the transgenic lines. Genetic manipulation of the flies altered their fecundity, but the heat shock had no effect on fecundity. To conclude, we have observed some costs of genetic manipulation by itself on life span and fecundity. However, the overexpression of the hsp70 extra copies by the exposure to heat did not alter the studied variables.

Analysis of Variance↗
PubMed2000

Size-specific fecundity and the influence of lifetime size variation upon effective population size in Abies balsamea.

The hierarchy of plant size often present in dense populations of plants and the close correlation found between size and fecundity can result in an unequal distribution of fecundity, which reduces the ratio of effective population size/census number (Ne/N). Such an effect has been found previously in annuals, but no study has hitherto tested for the effect in the lifetime fecundity variation of a perennial population. We use the demographically stable size distribution to be found in natural, wave-regenerating populations of balsam fir, Abies balsamea, in order to estimate Ne/N. In both wave-regenerating and normal forests our estimated values of Ne/N were about twice those previously reported for annuals. We suggest that fecundity variance is expected to be smaller in trees and other long-lived perennials than in annuals because density-dependent mortality operates more strongly in the prereproductive phase of long-lived plants.

Fertility↗
PubMed1990

Artificial insemination of Cashmere goats: effects on fertility and fecundity of intravaginal treatment, method and time of insemination, semen freezing process, number of motile spermatozoa and age of females.

The experiments, using a total of 1833 Cashmere does, were conducted to examine the effects on fertility and fecundity of intravaginal treatment for control of ovulation, time of insemination by cervical and laparoscopic methods, semen processing in pellets and straws, and number of frozen-thawed motile spermatozoa. Adult does (greater than or equal to 2.5 years) that had previously kidded were inseminated into the cervix, and maiden (kid: 6-8 months; hogget: 18 months) and adult does were inseminated laparoscopically. The rates of pregnancy determined by ultrasonic scanning (75-80 days after insemination) for cervical (Experiment 1) and laparoscopic (Experiments 2 and 3) insemination were 39.1%, 63.6% and 52.1%. The number of motile spermatozoa did not affect fertility after cervical (80, 120 and 160 x 10(6) or laparoscopic (Experiment 2: 15, 30 and 60 x 10(6); Experiment 3:5, 10 and 20 x 10(6) insemination. The method of insemination or number of motile spermatozoa did not affect fecundity. With cervical insemination, fertility and fecundity improved with increasing depth of insemination into the reproductive tract. Intravaginal sponges containing fluorogestone acetate and controlled internal drug release (CIDR) devices containing progesterone were equally effective for control of ovulation when combined with an injection of pregnant mare's serum gonadotrophin (PMSG; 200 i.u.) before insemination. Fertility was higher when does were inseminated before than after ovulation. After laparoscopic insemination, results were similar for semen frozen as pellets and in straws, and for 3-, 6- and 24-fold pre-freezing dilution of semen. For kid, hogget and adult does in Experiment 3, pregnancy rates were 34.0%, 55.4% and 63.9% and rates of fecundity were 1.17, 1.22 and 1.27 fetuses/pregnant doe.

Administration, Intravaginal↗
PubMed1996

Relative effects of female fecundity and male mating success on fertility selection in Drosophila pseudoobscura.

The fertility component of natural selection acting on chromosomal inversions in two experimental populations of Drosophila pseudoobscura was subdivided into the effects of female fecundity and male mating success. The offspring of the three female genotypes could be distinguished by their mitochondrial DNA haplotypes, thus permitting a direct measurement of the relative fecundities of the female genotype. The effects of male mating success on inversion frequency were measured by comparing inversion frequencies in parents and their offspring. Selection by fertility caused significant changes in inversion frequency in both populations. In one population, the changes in inversion frequency due to female fecundity and to male mating success were comparable. In the other population, however, the changes in inversion frequency due to male mating success were considerably larger than those due to female fecundity. The difference between the two populations underscores the intrinsic variability of the fertility component of fitness.

Animals↗
PubMed2002

Host location, survival and fecundity of the Oriental rat flea Xenopsylla cheopis (Siphonaptera: Pulicidae) in relation to black rat Rattus rattus (Rodentia: Muridae) host age and sex.

Host choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25 degrees C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat's presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50-70% decline in the initial number of adult fleas during the first week after their release onto a rat host, and this decline was greatest on juvenile rats. Flea fecundity was also significantly lower on juvenile rat hosts but no differences due to the sex of the rat were observed. This experimental study supports the hypothesis that differences in flea count due to host sex, reported in field surveys, result from sexual differences in host behaviour and not from discriminatory host-seeking behaviour by X. cheopis. Differences in flea count due to host age may be affected by differences in X. cheopis fecundity, which may itself be mediated by host behaviour such as grooming.

Animals↗