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PubMed2001

A field cage test of the effects of the endosymbiont Wolbachia on Drosophila melanogaster.

Wolbachia endosymbionts are known to affect the fitness of their hosts, but most of this information is from laboratory studies. In Drosophila melanogaster, Wolbachia frequencies vary clinically in frequency in Australia and may confound climatic adaptation. Here we use field cages in a reciprocal exchange design to test for Wolbachia effects in D. melanogaster in winter at temperate and tropical sites. Infected flies of both populations had a lower fecundity in tropical north Queensland, whilst in temperate southern Victoria Wolbachia effects depended on the nuclear population background. Here infected flies from Victoria were more fecund. Wolbachia also influenced larval/pupal viability in the tropics but this was dependent on population background. In comparisons of the populations, there was no evidence for local adaptation for total fecundity, viability or survival over winter. However, in Victoria, a local population had a higher late-life fecundity than a tropical population from Queensland that had higher early-life fecundity. At a tropical site, local Queensland flies had a higher early fecundity than Victorian flies. In contrast to many laboratory studies, mortality rates in the field cages increased only slightly over time. Both the Wolbachia effects and population differences have not been previously detected in laboratory studies with D. melanogaster and highlight the utility of Drosophila field studies in fitness experiments.

Analysis of Variance↗
PubMed1995

Effects of caffeine consumption on delayed conception.

The authors examined the effects of caffeine consumption on waiting time to conception in the Reproductive Health Study, a retrospective study of 1,430 non-contracepting, parous women interviewed between July 1989 and June 1990 at Fishkill, New York, and Burlington, Vermont. Information was obtained on 2,501 pregnancies since 1980. Women's reported consumption of caffeinated beverages during the first month of pregnancy was used to estimate daily caffeine intake, which was categorized as none, 1-150, 151-300, and > or = 301 mg. Information on delayed conception was analyzed as a dichotomous variable (< or = 12 months delay vs. > 12 months delay), and the per cycle probability of conception (fecundability) was estimated using waiting time to conception as a continuous variable. Odds ratios of delayed conception and fecundability ratios adjusted for age, parity, smoking, last contraceptive used, infertility history, and race, were estimated by logistic regression and Cox proportional hazard models, respectively. Women who did not smoke and who consumed no caffeine were used as a reference group. The adjusted odds ratio of delayed conception for more than one year was not increased among women who consumed < or = 300 mg of caffeine daily. However, the odds ratio (OR) was 2.65 (95% confidence interval (CI) 1.38-5.07) among nonsmokers who consumed > or = 301 mg of caffeine daily. Although smoking per se was associated with a significant increased risk of delayed conception (OR = 1.77, 95% CI 1.33-2.37), no effect of high caffeine consumption was observed among women who smoked. Fecundability was reduced among nonsmokers who consumed more than 300 mg caffeine daily (fecundability ratio = 0.74, 95% CI 0.59-0.92). Smoking reduced the fecundability ratio, but the authors observed no effect of caffeine consumption on fecundability among women who smoked. Other studies provide biologic plausibility for these findings. The authors conclude that high levels of caffeine consumption may result in delayed conception among women who do not smoke cigarettes.

Adult↗
PubMed2007

Copulation, genital damage and early death in Callosobruchus maculatus.

Antagonistic sexual coevolution stems from the notion that male and female interests over reproduction are in conflict. Such conflicts appear to be particularly obvious when male genital armature inflicts damage to the female reproductive tract resulting in reduced female longevity. However, studies of mating frequency, genital damage and female longevity are difficult to interpret because females not only sustain more genital damage, but also receive more seminal fluid when they engage in multiple copulations. Here, we attempt to disentangle the effects of genital damage and seminal fluid transfer on female longevity in the beetle Callosobruchus maculatus (Coleoptera: Bruchidae). Males copulating for the sixth time in succession inflicted greater levels of genital damage, but transferred smaller ejaculates in comparison with virgin males. The number of copulations performed by males was negatively related to female fecundity and positively related to female longevity, suggesting a trade-off between fecundity and longevity. However, inclusion of fecundity as a covariate revealed sperm and/or seminal fluid transfer to have a negative impact on female longevity above that caused by the fecundity-longevity trade-off. The consequences of multiple copulations on female longevity were examined. Females that mated twice laid more eggs and died sooner than those that mated once. However, incorporation of fecundity as a covariate into our statistical model removed the effect of female mating frequency on female longevity, indicating that double-mated females suffer greater mortality owing to the trade-off between fecundity and longevity. Males of this species are known to transfer very large ejaculates (up to 8% of their body weight), which may represent a significant nutritional benefit to females. However, the receipt of large ejaculates appears to carry costs. Thus, the interpretation of multiple mating experiments on female longevity and associated functional explanations of polyandry in this species are likely to be complex.

Animals↗
PubMed2003

Genetic variation in male effects on female reproduction and the genetic covariance between the sexes.

Males of many insect species increase the fecundity and/or egg size of their mates through the amount or composition of their nuptial gifts or ejaculate. The genetic bases of such male effects on fecundity or egg size are generally unknown, and thus their ability to evolve remains speculative. Likewise, the genetic relationship between male and female investment into reproduction in dioecious species, which is expected to be positive if effects on fecundity are controlled by at least some of the same genes in males and females, is also unknown. Males of the seed beetle Stator limbatus contribute large ejaculates to females during mating, and the amount of donated ejaculate is positively correlated with male body mass. Females mated to large males lay more eggs in their lifetime than females mated to small males. We describe an experiment in which we quantify genetic variation in the number of eggs sired by males (mated to a single female) and found that a significant proportion of the phenotypic variance in the number of eggs sired by males was explained by their genotype. Additionally, the number of eggs sired by a male was highly positively genetically correlated with his body mass. The between-sex genetic correlation, that is, the genetic correlation between the number of eggs sired by males and the number of eggs laid by females, was highly positive when eggs were laid on Acacia greggii seeds. This indicates that males that sire many eggs have sisters that lay many eggs. Thus, some of the genes that control male ejaculate size (or some other fecundity-enhancing factor) when expressed in males appear to control fecundity when expressed in females. We found no significant interaction between male and female genotype on fecundity.

Animals↗
PubMed2003

A comparative test of adaptive hypotheses for sexual size dimorphism in lizards.

It is commonly argued that sexual size dimorphism (SSD) in lizards has evolved in response to two primary, nonexclusive processes: (1) sexual selection for large male size, which confers an advantage in intrasexual mate competition (intrasexual selection hypothesis), and (2) natural selection for large female size, which confers a fecundity advantage (fecundity advantage hypothesis). However, outside of several well-studied lizard genera, the empirical support for these hypotheses has not been examined with appropriate phylogenetic control. We conducted a comparative phylogenetic analysis to test these hypotheses using literature data from 497 lizard populations representing 302 species and 18 families. As predicted by the intrasexual selection hypothesis, male aggression and territoriality are correlated with SSD, but evolutionary shifts in these categorical variables each explain less than 2% of the inferred evolutionary change in SSD. We found stronger correlations between SSD and continuous estimates of intrasexual selection such as male to female home range ratio and female home range size. These results are consistent with the criticism that categorical variables may obscure much of the actual variation in intrasexual selection intensity needed to explain patterns in SSD. In accordance with the fecundity advantage hypothesis, SSD is correlated with clutch size, reproductive frequency, and reproductive mode (but not fecundity slope, reduced major axis estimator of fecundity slope, length of reproductive season, or latitude). However, evolutionary shifts in clutch size explain less than 8% of the associated change in SSD, which also varies significantly in the absence of evolutionary shifts in reproductive frequency and mode. A multiple regression model retained territoriality and clutch size as significant predictors of SSD, but only 16% of the variation in SSD is explained using these variables. Intrasexual selection for large male size and fecundity selection for large female size have undoubtedly helped to shape patterns of SSD across lizards, but the comparative data at present provide only weak support for these hypotheses as general explanations for SSD in this group. Future work would benefit from the consideration of alternatives to these traditional evolutionary hypotheses, and the elucidation of proximate mechanisms influencing growth and SSD within populations.

Adaptation, Biological↗
PubMed2000

Differences in the effect of ethanol on fertility and viability components among laboratory strains of Drosophila melanogaster.

We studied the effect of ethanol on several fitness components in six Drosophila melanogaster strains. Mating success, fecundity, egg-to-larva, egg-to-pupa and egg-to-adult survival and the number of emerging adults were estimated in a single series of experiments. The strains either had different combinations of genetic background and Adh genotypes with identical OdhF genotype or different Adh-Odh two-locus genotypes with similar genetic background. Ethanol had the greatest effect on mating success and fecundity, while its influence was lower on survival. When the experimental conditions were contrasted to the natural environment of the flies the most significant results were the ones related to fecundity and larval survival. Ethanol had the highest selective effect on fecundity. The genetic factors contributed substantially to the variation in the fertility and viability components. The Adh locus hardly influenced mating success while it had a sizable effect on fecundity and on all survival components. The influence of Adh on fecundity greatly depended on the other genetic factors. Genetic background had the largest influence on the different survival components. The influence of the Odh locus was mostly observed through the Adh-Odh interaction.

Alleles↗
PubMed1994

Time to pregnancy and occupational exposure to pesticides in fruit growers in The Netherlands.

OBJECTIVES: Although pesticides are regularly used in agriculture, relatively little is known about possible adverse health effects, especially reproductive effects, due to occupational exposure. This explorative study investigates the relation between exposure of the fruit grower to pesticides and fecundability (probability of pregnancy) in a population of fruit growers. METHODS: The analysis is based on self reported data and includes 91 pregnancies during 1978-1990 of 43 couples. Cox' proportional hazards model was used to analyse time to pregnancy after correction for gravidity and consultation with a physician for fertility problems. RESULTS AND CONCLUSIONS: Application of pesticides solely by the owner was associated with a long time to pregnancy, resulting in a fecundability ratio of 0.46 (95% confidence interval (95% CI) 0.28-0.77). Similarly a low spraying velocity (< or = 1.5 hectares/h) resulted in a fecundability ratio of 0.47 (95% CI 0.29-0.76) and is associated with the use of older spraying techniques and tractors without a cabin. These factors were assumed to cause high exposure, which was confirmed by exposure measurements in the field. The effect of high exposure was mainly apparent if the couple had intended to become pregnant in the period from March-November (fecundability ratio 0.42, 95% CI 0.20-0.92). This is the period in which pesticides are applied. Out of the spraying season the effect of a high exposure was absent (fecundability ratio 0.82, 95% CI 0.33-2.02). In the high exposure group 28% of the pregnancies had been preceded by consulting a physician because of fertility problems, compared with 8% in the low exposure group. These findings indicate that an adverse effect of exposure to pesticides on fecundability is likely.

Adult↗
PubMed2001

Solvent use and time to pregnancy among female personnel in biomedical laboratories in Sweden.

OBJECTIVES: To elucidate possible effects on fecundability from chemical, biological, and physical agents in laboratories, a retrospective study based on a questionnaire was conducted among female personnel who worked in Swedish biomedical research laboratories. Female personnel in non-laboratory departments were used as a reference group. The maximum number of women included in the analyses was 560. This corresponded to 2519 menstrual cycles. These women had given birth at least once during the period 1990-4. METHODS: Time to pregnancy was used to estimate the fecundability-that is, probability of conception of a clinically detectable pregnancy per cycle. The fecundability ratio (FR) between exposed and unexposed cycles was calculated with a discrete time analogue of the Cox's proportional-hazards model. The FR estimates below unity indicate subfecundity. RESULTS: Work with organic solvents in general in laboratory work, gave a decreased adjusted fecundability ratio (FR) of 0.79 (95% confidence interval (95 % CI) 0.68 to 0.93). Moreover, work with acetone and use of viruses also showed decreased FRs, 0.72 (0.53 to 0.97) and 0.66 (0.49 to 0.90), respectively. CONCLUSIONS: The results of the present study give some indications of reduced fecundability for work with specific agents in laboratories, and support previously reported findings of a negative influence of organic solvents on fecundity among female laboratory personnel.

Adult↗
PubMed2001

Factors affecting reproduction and the importance of adult size on reproductive output of the midge Chironomus tentans.

We conducted two separate tests to evaluate the influence of several factors that could affect estimation and interpretation of effects on reproductive output of Chironomus tentans in sediment toxicity tests. Specifically, the influence of adult size, mating frequency in males (male), and age of both males and females (female) at first mating on mating success (number of successful matings), fecundity (number of eggs/female), percentage hatch, and number of offspring (number of hatched eggs) was assessed. In the first experiment, the influence of adult size on reproductive output was determined by growing midges fed a low (0.29 mg/individual/d) and a high (0.42 mg/individual/d) amount of food to produce small (S) and large (L) adults, respectively. The adults were then mated in one of four scenarios: S male x S female, S male x L female, L male x S female, and L male x L female. An increase in male weight at a constant female weight had no significant effect on fecundity, whereas an increase in female weight yielded 49.5 and 60.7% increases in fecundity when mated with low- and high-fed males, respectively. Similarly, mean number of offspring (fecundity x percent hatch) increased by 19.8 and 48.3% when male weight was increased and female weight was held constant and by 141.9 and 180.4% when female weight was increased and male weight was held constant. In the second experiment, conducted at a single feeding rate, fecundity increased significantly with an increase in female weight but not male weight. The number of offspring was not significantly influenced by adult weight. The age of males or females at first mating, the frequency with which males were mated (up to seven consecutive days), and the proportion of males successfully mating had no effect on fecundity or number of offspring; however, large increases in variability about mean estimates were observed in some endpoints for older males. These results suggest that adult female size is the most important factor affecting reproductive output in C. tentans, and that enhanced performance of the life-cycle test with respect to all reproductive endpoints might be achieved if males are not mated for more than five consecutive days.

Animals↗
PubMed2000

Time to pregnancy among female greenhouse workers.

OBJECTIVES: This study examined the possibility that work in greenhouses with potential exposure to pesticides entails a risk for reduced fecundity in terms of increased time to pregnancy. METHODS: Among 1767 female members of the Danish Gardeners Trade Union, telephone interview data were obtained on the 492 most recent pregnancies of women employed when they stopped contraception to get a child (the starting time). The pregnancies were classified according to job characteristics at the starting time. The ratio between the likelihood of pregnancy during a month for the exposed persons versus the referents (the fecundability ratio) was estimated by discrete proportional hazards regression. RESULTS: The adjusted fecundability ratio for workers in flower greenhouses versus other union members was 1.11 [95% confidence interval (95% CI) 0.90-1.36]. Among workers in flower greenhouses the handling of cultures many hours per week, the spraying of pesticides, and the nonuse of gloves was related to reduced fecundability [adjusted fecundability ratio 0.69 (95% CI 0.47-1.03), 0.78 (95% CI 0.59-1.06), and 0.67 (95% CI 0.46-0.98), respectively]. CONCLUSIONS: The findings suggest that female workers in flower greenhouses may have reduced fecundability and that exposure to pesticides may be part of the causal chain. Additional studies of fertility among women working in greenhouses are highly warranted.

Adult↗
PubMed1998

Adult and prenatal exposures to tobacco smoke as risk indicators of fertility among 430 Danish couples.

During 1992-1995, 430 Danish couples were recruited after a nationwide mailing of a letter to 52,255 trade union members who were 20-35 years old, lived with a partner, and had no children. The couples were enrolled into the study when they discontinued birth control, and they were followed for six menstrual cycles or until a clinically recognized pregnancy. At enrollment and each month throughout the follow-up, both partners completed a questionnaire that asked them about their smoking, alcohol consumption, and intake of caffeinated beverages. The effect of current smoking and smoking exposure in utero was evaluated by using a logistic regression model with pregnancy outcome of each cycle in a Cox discrete model calculating the fecundability odds ratio. After adjustment for female body mass index and alcohol intake, diseases in female reproductive organs, semen quality, and duration of menstrual cycle, the fecundability odds ratio for smoking women exposed in utero was 0.53 (95% confidence interval (CI) 0.31-0.91) compared with unexposed nonsmokers. Fecundability odds ratio for nonsmoking women exposed in utero was 0.70 (95% CI 0.48-1.03) and that for female smokers not exposed in utero was 0.67 (95% CI 0.42-1.06). Exposure in utero was also associated with a decreased fecundability odds ratio in males (0.68, 95% CI 0.48-0.97), whereas present smoking did not reduce fecundability significantly. It seems advisable to encourage smoking cessation prior to the attempt to conceive as well as during pregnancy.

Adolescent↗
PubMed1998

Sexual selection and the fitness consequences of male body size in the seed beetle Stator limbatus

We examined sexual selection on male body size in a laboratory population of the seed beetle, Stator limbatus, and the fitness consequences to females of mating with larger males. Large males produced larger ejaculates than small males. Both males and females lost body weight as a consequence of breeding, and large males lost more weight than small males. The amount of weight lost by males correlated as highly with female fecundity as did the amount of weight lost by females. Similarly, male and female body weight correlated equally highly with female fecundity. These results indicate that males make substantial contributions to female fecundity, probably through nutrients transferred in their ejaculate. As a consequence, fecundity selection should favour large body size in both males and females. We found no preference for large males when virgin females were presented with only one male, but when presented with two males simultaneously, females were more likely to mate with the larger male. This result is consistent with relative female choice or male-male competition, although no indications of male-male competition were observed. Females that mated with small males re-mated sooner than females that first mated with large males. Females that first mated with a non-virgin male were also more likely to re-mate than females that first mated with a virgin male, suggesting that females re-mate to obtain additional sperm or nutrients and not just as a form of mate choice. In addition to the possible benefits from mate choice and male-male competition, large males gain a mating advantage through reduced sperm competition. This large male advantage, combined with fecundity selection on males as well as females, may account for males being larger than females in this species.Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2005

Larval food limitation in butterflies: effects on adult resource allocation and fitness.

Allocation of larval food resources affects adult morphology and fitness in holometabolous insects. Here we explore the effects on adult morphology and female fitness of larval semi-starvation in the butterfly Speyeria mormonia. Using a split-brood design, food intake was reduced by approximately half during the last half of the last larval instar. Body mass and forewing length of resulting adults were smaller than those of control animals. Feeding treatment significantly altered the allometric relationship between mass and wing length for females but not males, such that body mass increased more steeply with wing length in stressed insects as compared to control insects. This may result in changes in female flight performance and cost. With regard to adult life history traits, male feeding treatment or mating number had no effect on female fecundity or survival, in agreement with expectations for this species. Potential fecundity decreased with decreasing body mass and relative fat content, but there was no independent effect of larval feeding treatment. Realized fecundity decreased with decreasing adult survival, and was not affected by body mass or larval feeding treatment. Adult survival was lower in insects subjected to larval semi-starvation, with no effect of body mass. In contrast, previous laboratory studies on adult nectar restriction showed that adult survival was not affected by such stress, whereas fecundity was reduced in direct 11 proportion to the reduction of adult food. We thus see a direct impact of larval dietary restriction on survival, whereas fecundity is affected by adult dietary restriction, a pattern reminiscent of a survival/reproduction trade-off, but across a developmental boundary. The data, in combination with previous work, thus provide a picture of the intra-specific response of a suite of traits to ecological stress.

Animal Nutritional Physiological Phenomena↗
PubMed2001

Controlled ovarian hyperstimulation and intrauterine insemination for treatment of unexplained infertility should be limited to a maximum of three trials.

OBJECTIVE: To investigate the optimum number of cycles of controlled ovarian hyperstimulation and intrauterine insemination in the treatment of unexplained infertility. DESIGN: Observational prospective study. SETTING: In vitro fertilization embryo transfer center. PATIENT(S): Five hundred ninety-four couples with unexplained infertility. INTERVENTION(S): Controlled ovarian hyperstimulation (COH), intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI). MAIN OUTCOME MEASURE(S): Cycle fecundity. RESULT(S): One to 3 cycles of COH/IUI were performed in 594 patients (group A) undergoing 1,112 cycles (mean, 1.9 cycles/patient). Up to 3 further trials (cycles 4-6) of COH/IUI were then performed in 91 of these women (group B), a total of 161 cycles (mean, 1.8 cycles/patient). A historical comparison group C consisted of 131 patients with 3 failed cycles of COH/IUI who underwent 1 cycle of IVF and ICSI at our center. In group A, 182 pregnancies occurred, with a cycle fecundity of 16.4% and a cumulative pregnancy rate (PR) of 39.2% after the first 3 cycles. In group B, 9 pregnancies occurred in cycles 4-6, with a cycle fecundity of 5.6%, significantly lower than that of group A (P<.001). The cumulative PR rose to 48.5% by cycle 6, a further increase of only 9.3%. In the women undergoing IVF and ICSI in group C, 48 pregnancies occurred, with a cycle fecundity of 36.6% per cycle, significantly higher than that of group B (P<.001). CONCLUSION(S): In unexplained infertility, the cycle fecundity in the first three trials of COH and IUI was higher than in cycles 4-6, with a statistically significant difference. Patients should be offered IVF or ICSI if they fail to conceive after three trials of COH and IUI.

Adult↗
PubMed1993

Relative infertility: modeling clinical paradoxes.

OBJECTIVES: To assume that a cause of relative infertility will decrease the monthly chance of conception (fecundability) in a dose-dependent manner and, by a mathematical model, to identify common clinical observations and paradoxes that are explainable within this hypothesis. DESIGN: An empirically based assumption of a population-mean fecundability of 0.2 and the accumulating probability of pregnancy equations and projections were used to examine over time the effects of diminishing such fecundability to one half, one fifth, and one twentieth of normal, and then reversing this effect with ideal treatment at points of 2 years and 5 years. RESULTS: [1] The duration of infertility is an important and powerful covariate in determining residual fecundability and the chance of pregnancy, with or without treatment. [2] The more substantial the pathology is, the greater should be the likelihood of pregnancy after its effective treatment. [3] Provided no harm is done by treatment, an increase in subsequent fecundability will result whatever the "dose" of the reproductive disturbance, but this will not always mean that pregnancy is probable. [4] The presence of a second infertility factor should compound dramatically the deleterious effects attributable to the first and make it more likely for either factor to be diagnosed. CONCLUSIONS: Duration of infertility is generally more important than the dose of an infertility factor as a covariate in clinical studies, and more emphasis should be placed on controlling for it. Discouraging clinical reports on the low success of treating certain conditions associated with infertility do not necessarily justify rejecting a hypothesis that such a condition decreases fertility in a dose-dependent manner.

Female↗
PubMed1994

The value of increasing the dose of human menopausal gonadotropins in women who initially demonstrate a poor response.

OBJECTIVE: To evaluate the benefit of increasing the hMG dose in subsequent superovulation cycles for those individuals who demonstrate a poor response on up to three ampules of hMG daily. DESIGN AND SETTING: Retrospective analysis of all superovulation cycles at the University of Connecticut Health Center. PATIENTS: All women undergoing hMG therapy with IUI from January 1990 until December 1992. INTERVENTIONS: All patients were initially stimulated with up to three ampules of hMG daily. All patients who did not conceive on their first hMG cycle and demonstrated a poor response to hMG therapy were started on higher doses of hMG in an effort to obtain a good response. A maximum of eight ampules of hMG per day were used. MAIN OUTCOME MEASURES: Peak serum E2, the number of mature preovulatory follicles, and cycle fecundity were compared. RESULTS: The poor responders using up to three ampules daily had a peak E2 of 384 +/- 26 pg/mL (1,421 +/- 96 pmol/L), 1.4 +/- 0.1 mature follicles, and a cycle fecundity of 3.1% compared with an E2 of 900 +/- 83 pg/mL (3,330 +/- 307 pmol/L), 2.7 +/- 0.2 mature follicles, and a cycle fecundity of 4.3% when these poor responders had their dose increased to five or more ampules daily. Those individuals demonstrating a good response on less than or equal to three ampules of hMG daily had an average peak E2 of 1,159 +/- 41 pg/mL (4,288 +/- 151 pmol/L), 3.4 +/- 0.2 mature follicles, and a cycle fecundity of 16.5%. CONCLUSIONS: Despite significant improvement in peak E2 and the number of mature preovulatory follicles when the hMG dose was increased in poor responders, no significant increase in cycle fecundity was noted.

Adult↗
PubMed1995

Selective use of leuprolide acetate in women undergoing superovulation with intrauterine insemination results in significant improvement in pregnancy outcome.

OBJECTIVE: To examine the incidence of premature luteinization in individuals undergoing hMG with IUI therapy, the association between premature luteinization, cycle fecundity, and pregnancy outcome, and to determine if the selective use of leuprolide acetate (LA) in women demonstrating premature luteinization improves pregnancy outcome in subsequent hMG with IUI cycles. DESIGN AND SETTING: Retrospective analysis of superovulation cycles from January 1990 until December 1991 at the University of Connecticut Health Center. PATIENTS: All women with ovulatory function undergoing hMG superovulation with IUI. INTERVENTIONS: All patients were tested for evidence of premature luteinization. Those demonstrating premature luteinization were started on LA in the luteal phase in their subsequent hMG with IUI cycle. MAIN OUTCOME MEASURES: Peak serum E2, the number of mature preovulatory follicles, the number of ampules of hMG, days of hMG therapy, cycle fecundity, and spontaneous abortion rate. RESULTS: Thirty-three percent of all hMG with IUI patients showed evidence of premature luteinization, with premature luteinization occurring in 22.2% of conception cycles and 37.4% of nonconception cycles. For those women who demonstrated premature luteinization in their conception cycle, 90.0% of the pregnancies ended with either spontaneous abortion or were biochemical in nature compared with 44.3% in the cycles without evidence of premature luteinization. Cycle fecundity was 11.1% in patients demonstrating premature luteinization compared with 26.3% for patients without premature luteinization. All women demonstrating premature luteinization and not conceiving were placed on LA in the luteal phase and had a subsequent cycle fecundity of 18.9% with the percent pregnancy wastage being significantly less (33.3% versus 90.0%) when LA was used. CONCLUSIONS: Premature luteinization is a common occurrence during hMG therapy and is associated with decreased cycle fecundity and an increased incidence of spontaneous abortion and biochemical pregnancies. The selective use of LA in those individuals demonstrating premature luteinization results in a significant increase in the percent of women conceiving a viable pregnancy.

Abortion, Spontaneous↗
PubMedDate not supplied

Aging, fertility, and immortality.

Evolutionary theory suggests that fecundity rates will plateau late in life in the same fashion as mortality rates. We demonstrate that late-life plateaus arise for fecundity in Drosophila melanogaster. The result qualitatively fits the evolutionary theory of late life based on the force of natural selection. But there are a number of alternative interpretations. Fecundity plateaus could be secondary consequences of mortality-rate plateaus. Female fecundity plateaus might arise from diminished male sexual function. Another alternative hypothesis is analogous to male sexual inadequacy: nutritional shortfalls. These may arise later in life because of a decline in female feeding or digestion. If some females have a life-long tendency to lay eggs at a faster rate, but die earlier, then aging for fecundity could arise from the progressive loss of the fast-layers, with the late-life plateau simply the laying patterns of individual females who were slow-layers throughout adult life. If this type of model is generally applicable to late life, then we should find that the females who survive to lay at a slow but steady rate in late life have a similar laying pattern in mid-life.

Aging↗