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Highly restricted fertility: very small families in the British fertility decline.

From the earliest stages of the British fertility decline, falling mean family size was accompanied by marked rises in the proportion of married women who remained childless or who bore only a single child. This paper summarises those changes, their impact on average family size, and the implications for estimates of the proportions of couples who attempted to space their children in the early years of marriage. The explanatory power of some commonly cited interpretations of the general decline in marital fertility is then considered in the context of this growth in number of families of highly restricted fertility. The paper highlights a need for more emphasis on descriptive and analytical approaches that are sensitive to distributions within populations. Also emphasized is the importance of developing interpretations that allow for the possibility that different factors may operate on different sub-sets of families at different points in time.

Birth Rate↗

In-vitro fertilization treatment for severe male factor: the fertilization potential of immotile spermatozoa obtained by testicular extraction.

A retrospective analysis in 50 couples of 53 cycles of intracytoplasmic sperm injection (ICSI) with immotile spermatozoa from testicular-retrieved spermatozoa was performed to evaluate whether total immotile spermatozoa achieved after testicular sperm extraction could fertilize ova and result in pregnancies. We assessed the efficacy of ICSI with totally immotile testicular spermatozoa extracted from the testes of azoospermic patients with severe spermatogenic failure (group 1) and compared these results with those from spermatozoa which were recovered after several hours of incubation and were motile (group 2) at the time of injection. In 19 cycles, only totally immotile spermatozoa were injected at the time of ICSI. For the remaining 34 cycles, at least one motile spermatozoon was found for injection. The oocyte fertilization rates were 51% for group 1 and 62% for group 2 (P < 0.02). Eighteen of 19 cycles in group 1 (90%) and all 34 (100%) cycles in group 2 had embryos for replacement. The mean number of embryos per cycle was 5.2 +/- 0.8 and 7.5 +/- 0.9 in groups 1 and 2 respectively; this and the embryo quality (cumulative embryo scoring = 40 +/- 8 for group 1 and 50 +/- 7 for group 2), and clinical pregnancy rates (15.8% per oocyte retrieval in group 1 and 23.5% in group 2) were not significantly different between groups. Fertilization, cleavage and pregnancy can be achieved with intracytoplasmic testicular sperm injection from patients with immotile spermatozoa, at levels comparable with those of ICSI using motile spermatozoa.

Adult↗

Fertilization abnormalities in human in-vitro fertilization.

Fertilization abnormalities (premature chromosome condensation of spermatozoa (PCC), triploidy, haploidy) were analysed in order to determine their origin. PCC occurs in 9% of unfertilized oocytes and seems to be the consequence of a failure of oocyte activation, leading to the continuing presence of cytoplasmic chromosome-condensing factors, causing the sperm nucleus to undergo chromosome condensation prematurely. This anomaly appears to be related to incomplete nuclear and/or cytoplasmic maturation. Triploid zygotes (6.5% of fertilized oocytes) display an original type of division: half of them divide into 3 and 6 cells, whereas at the same time diploid zygotes divide into 2 and then 4 cells. A cytological study, using both antitubulin antibodies and Hoechst dye, allowed us to demonstrate that they divide into 3 cells by means of a tripolar spindle. Triploidy seems to be correlated with four of 16 clinical or biological parameters examined: semen origin (fresh or frozen), type of stimulation treatment, number of oocytes recovered and embryo morphology. Haploid eggs (1.6% of inseminated oocytes) result from parthenogenetic activation. A correlation was found between a high number of recovered oocytes and triploid zygotes, and the occurrence of oocyte activation. These data show that increasing follicular recruitment decreases the overall oocyte quality and maturity leading to an overall 9% with impaired fertilization.

Chromosome Aberrations↗

Intracytoplasmic sperm injection does not overcome an oocyte defect in previous fertilization failure with conventional in-vitro fertilization and normal spermatozoa.

A cohort comprising a total of 447 oocyte aspirations due to male factors (n = 258) or to previous fertilization failure by IVF in the presence of normal sperm parameters (n = 189) was studied. We found a significantly reduced implantation and pregnancy rate per transfer in the group with previously failed IVF attempts compared to the male factor group (P < 0.001). No differences were found in age, number of oocytes retrieved, number of embryos transferred or quality of embryos scored at the time of transfer. However, the fertilization and cleavage rates were found to be reduced in the group with previous failed IVF cycles. It is therefore concluded that previous fertilization failure despite normal sperm parameters in an IVF cycle may not be alleviated by the intracytoplasmic sperm injection (ICSI) procedure. These patients might suffer from oocyte defects as well.

Cytoplasm↗

Human chorionic gonadotrophin and steroid concentrations in follicular fluid: the relationship to oocyte maturity and fertilization rates in stimulated and natural in-vitro fertilization cycles.

The study investigates the relationship of follicular fluid steroids and human chorionic gonadotrophin to oocyte maturity and fertilization rates in stimulated and natural cycles. Oestradiol, progesterone, testosterone and human chorionic gonadotrophin were quantified in 129 samples of follicular fluid and the progesterone:oestradiol ratio calculated. Both stimulated cycles (short and long luteinizing hormone-releasing hormone/human menopausal gonadotrophin regimens) and natural cycles were compared. A total of 60 women were studied, 20 in each group. In the natural cycles, testosterone was significantly lower in follicles with intermediate oocytes (P = 0.015). Both oestradiol and testosterone were significantly lower in stimulated cycles compared to natural cycles (P = 0.032 and P = 0.034 respectively). In the ovarian stimulation cycles, the progesterone:oestradiol ratio was significantly higher when oocytes fertilized (P = 0.052). Moreover, in the stimulated cycles, oestradiol and human chorionic gonadotrophin were singnificantly lower in the short protocol compared to the long protocol. The data demonstrate that the hormonal milieu of the follicle is altered in down-regulated stimulated cycles to varying degrees, depending partially on the type of protocol used. Furthermore, the progesterone:oestradiol ratio, rather than individual hormone concentrations, may be a useful predictor of the fertilizing capacity of the oocytes.

Adult↗

Effect of hypotaurine on in vitro fertilization and production of term offspring from in vitro-fertilized ova of the Japanese field vole, Microtus montebelli.

The present study was proposed to establish new in vitro fertilization (IVF)-embryo transfer techniques for wild mammals. We demonstrated that IVF of the Japanese field vole, Microtus montebelli, is improved by hypotaurine, and that IVF vole embryos can develop to normal offspring after transfer to recipient females. The rate of IVF was significantly increased when 0.1 or 1 mM of hypotaurine was added during sperm preincubation and fertilization (p < 0.05). Preincubation of spermatozoa with 1 mM hypotaurine prior to oocyte insemination did not have a significant effect on fertilization rate (p < 0.01). At 96 h after insemination, most cultured embryos developed to the 2-cell stage (68-83%), but development to blastocysts was very low (0-3%) for all treatments. Although 43 living offspring were produced after transfer of IVF pronuclear embryos to recipients, the delivery rate of recipients was very low (21%). The litter size of pseudopregnant recipients that produced a litter was 4-11, and the rate of in vivo development of transferred embryos in the pregnant recipients was 41%. These results suggest that hypotaurine affects IVF rather than sperm preincubation and that IVF embryos can develop to normal offspring.

Animals↗

Socio-economic status and fertility of couples examined for infertility, social status and fertility.

The clinical Fertility of 1000 couples consecutively examined for infertility during 1950-52 was assessed 20 years later by means of a questionnaire, and results were compared with their socio-economic class as defined by the Svalastoga classification. Examinations had included semen analysis performed in our laboratory. 51 couples with known sterility because of azoospermia were excluded. The questionnaire was returned by 691 (72.8%). Couples of higher classes obtained more children (p less than 0.01) than those of lower classes, and they obtained, consistently, their first child in shorter time (p less than 0.01). Semen analysis showed better parameters of spermatozoa motility in higher classes, but the morphology was poorer, and there was no relation to socio-economic class when the different characteristics of semen analysis were combined according to the Hammen classification system of semen quality. It is discussed that the better fertility prognosis of couples of higher socio-economic classes not explained by a difference in semen quality of the men may indirectly indicate that females of lower classes suffered from more severe gynaecological diseases and abnormalities combined with a reduced fertility potential.

Epidemiologic Methods↗

Home monitoring with the ClearPlan Easy Fertility Monitor for fertility awareness.

Many couples planning a pregnancy have had to gauge the best time for sexual intercourse from subjective indications, e.g. cervical mucus changes, or retrospective information, e.g. temperature and calendar methods. Between women, and within a woman, there are considerable variations in menstrual cycle length and underlying hormonal patterns. Although fertility test kits are available, most still rely on visual interpretation by the user. A new combination of immunochemical testing and computing technology is now available in the ClearPlan Easy Fertility Monitor. This paper describes the features of this accurate, simple-to-use, home-based fertility monitor, which gathers data on hormonal patterns and takes account of the individuality of menstrual cycles in women. These data and information about other events, such as sexual intercourse, can be stored in the monitor and accessed by the couple and their medical professional for retrospective review. The monitor is useful for couples who have just started trying to conceive, or those who have been planning a pregnancy for some time.

Estrone↗

Alkyl phenols and diethylhexyl phthalate in tissues of sheep grazing pastures fertilized with sewage sludge or inorganic fertilizer.

We studied selected tissues from ewes and their lambs that were grazing pastures fertilized with either sewage sludge (treated) or inorganic fertilizer (control) and determined concentrations of alkylphenols and phthalates in these tissues. Mean tissue concentrations of alkylphenols were relatively low (< 10-400 microg/kg) in all animals and tissues. Phthalates were detected in tissues of both control and treated animals at relatively high concentrations (> 20,000 microg/kg in many tissue samples). The use of sludge as a fertilizer was not associated with consistently increased concentrations of either alkylphenols or phthalates in the tissues of animals grazing treated pastures relative to levels in control animal tissues. Concentrations of the two classes of chemicals differed but were of a similar order of magnitude in liver and muscle as well as in fat. Concentrations of each class of compound were broadly similar in tissues derived from ewes and lambs. Although there were significant differences (p < 0.01 or p < 0.001) between years (cohorts) in mean tissue concentrations of both nonylphenol (NP) and phthalate in each of the tissues from both ewes and lambs, the differences were not attributable to either the age (6 months or 5 years) of the animal or the duration of exposure to treatments. Octylphenol concentrations were generally undetectable. There was no consistent cumulative outcome of prolonged exposure on the tissue concentrations of either class of pollutant in any ewe tissue. Mean tissue concentrations of phthalate were higher (p < 0.001) in the liver and kidney fat of male compared with female lambs. We suggest that the addition of sewage sludge to pasture is unlikely to cause large increases in tissue concentrations of NP and phthalates in sheep and other animals with broadly similar diets and digestive systems (i.e., domestic ruminants) grazing such pasture.

Animals↗

Development of in vitro fertilized feline embryos in a modified Earle's balanced salt solution: influence of protein supplements and culture dishes on fertilization success and blastocyst formation.

The effects of protein supplements and culture dish type on in vitro fertilization (IVF) and embryo development in culture were examined in the domestic cat. In Experiment I, follicular oocytes were fertilized and cultured in either 1) modified Earle's balanced salt solution, designated MK-1, supplemented with one of the following: 10% human serum (HS), 10% FCS or 0.4% BSA, or 2) Medium 199 (M-199) supplemented with 10% FCS. Fertilization rates were lower (P < 0.01) in MK-1 + BSA (74.4%), MK-1 + FCS (56.1%), and M-199 + FCS (51.4%) than in MK-1 + HS (94.7%). A greater (P < 0.01) percentage of blastocysts was obtained in MK-1 + HS (50.0%) than in other treatment groups (range, 4.3-17.2%). In Experiment II, the effect of dish type (tissue culture dish, TCD, versus suspension culture dish, SCD) on embryo development was evaluated in MK-1 supplemented with either HS or BSA. Significantly higher proportions of IVF-derived embryos developed to blastocysts at 120 and 144 hr post-insemination, respectively, when cultured in HS/SCD (47.2 and 71.7%) than in BSA/SCD (11.4 and 27.3%) or BSA/TCD (10.4 and 25.0%). At 120 hr post-insemination, there was a lower (P < 0.01) percentage of blastocysts in HS/TCD (22.2%) than in HS/SCD. In Experiment III, six embryos per cat were transferred to the uterine horns of 17 recipients at 144 hr after hCG treatment. Five of 7 recipients which received late morulae cultured in MK-1 + BSA (SCD) for 120 hr became pregnant (71.4%). Eight of 10 recipients which received early blastocysts cultured in MK-1 + HS (SCD) for 120 hr became pregnant (80.0%). We conclude that MK-1 containing HS is highly beneficial for overcoming the in vitro developmental block of IVF-derived feline embryos and increasing the success rate of IVF/ET.

Animals↗

Blood selenium, vitamin E, vitamin A, and beta-carotene concentrations and udder health, fertility treatments, and fertility.

We investigated the activity of glutathione peroxidase in whole blood; concentrations of vitamin E, vitamin A, and beta-carotene in serum; SCC; udder bacterial infections and the incidence of clinical mastitis; fertility treatments; and the success of first AI of 511 dairy cows for 1 yr. The mean Se content in whole blood and the concentrations of vitamin E, vitamin A, and beta-carotene concentrations in serum were 191 micrograms/L, 5.9 mg/L, 0.39 mg/L, and 12.9 mg/L, respectively. An increase in Se concentration in whole blood was associated with a decrease in all infections, including infections by Staphylococcus aureus, Actinomyces pyogenes, and Corynebacterium spp. (-17.7, -31.7, and -70.6%, respectively). There was no association among the different infections or SCC and concentrations of vitamin E, vitamin A, or beta-carotene, but an association existed between vitamin A concentration and SCC. The lower Se concentration in whole blood did not increase incidence of clinical mastitis. The Se concentration in whole blood (200 micrograms/L) was accepted as a target value to optimize udder health. The incidence of fertility disorders (anestrus, subestrus, cystic ovaries, or delayed ovulation) was 34.4%. The pregnancy rate following first insemination was 48.6%. No significant association was observed among Se in whole blood; concentrations of total vitamin E, vitamin A, or beta-carotene in serum; and fertility disorders or success of first AI.

Animals↗

[Changes of crop yields and soil fertility under long-term application of fertilizer and recycled nutrients in manure on a black soil].

The results from a field experiment over thirteen years on a black soil in Northeast China indicated that nitrogen fertilizer increased crop yields by 724 kg.hm-2 per year on average, with an increase rate of 27.5% and about 9.4 kg increased yield from 1 kg applied N. In the early stage, the crop yields almost gave no response to phosphorus fertilizer, owing to the high level of soil available phosphorus at the beginning of the experiment. The average increase of crop yields by phosphorus in thirteen years was only 241 kg.hm-2 per year, with an increase rate of 7%, about 12.7 kg increased yield from 1 kg applied P. Annual application of recycled pig manure made by 80% of harvested grain fed to pigs and the stolks as bedding materials could increase crop yields by 268, 258 and 255 kg.hm-2 per year with an increase rate of 9.8%, 7.6% and 7.0%, based on no fertilizer, with N and with P and N, respectively. There was a trend that the effect of recycled manure on crop yield was gradually increased during the period of experiment, implying the existence of accumulative residual effect from the manure.

Agriculture↗

[Soil fertility evolution, nutrient balance and reasonable fertilization in paddy field in southern area of Jiangsu Province].

With the integration of macro-statistical data, micro-survey data and parameters obtained from previous studies, the soil fertility evolution and nutrient balance in paddy fields in southern Jiangsu were analyzed to provide evidence of scientific fertilizer application. It was showed that from 1982 to 1996, the total nitrogen and organic matter contents in Wuxi paddy fields had a rapid increase, phosphorus had a slow increase, and potassium had a general decrease. Soil nutrient balance analysis in Wuxi and Changzhou cities showed that nitrogen was commonly surplus, potassium was generally inadequate, and phosphorus was different from nitrogen and potassium. Phosphorus was surplus in Wuxi city and inadequate in Changzhou city. On the basis of nutrient balance, the reasonable nitrogen, phosphorus and potassium fertilizer application amount was 488.9, 113.1 and 235.1 kg.hm-2 in Wuxi, and 499.4, 112.5 and 234.2 kg.hm-2 in Changzhou paddy fields, respectively. Due to the nitrogen accumulation and potassium absence in soil, the nitrogen and potassium application amount should be lower and higher than the above reasonable nitrogen and potassium application amount.

Fertilizers↗

In-vitro fertilization pregnancies in Australia and New Zealand, 1979-1985. Australian In-Vitro Fertilization Collaborative Group.

We report here data on 1510 pregnancies that resulted from in-vitro fertilization in 12 in-vitro fertilization units in Australia and in one unit in New Zealand in the period 1979 to 1985. Live births occurred in 57.5% of all pregnancies (including preclinical abortions) and in 69.0% of clinical pregnancies. There was a high incidence of ectopic pregnancies (5.2% of clinical pregnancies) and spontaneous abortions (24.3% of intrauterine pregnancies). Of 902 viable pregnancies, 202 (22.4%) pregnancies resulted in multiple births. There were 700 infants who were born after singleton births and 438 infants who were born after multiple births. The over-all incidence of preterm delivery was 27.0%, with an incidence of 18.5% of singleton pregnancies. Low birth weight occurred in 34.8% of infants. The perinatal death rate was 47.5 deaths per 1000 births; still births accounted for three-quarters of these deaths. These findings can be used to counsel infertile couples about the risks of reproductive losses after treatment by in-vitro fertilization. National health surveys should include questions that relate to the prevalence of infertility to encourage studies of the prevention of infertility and to assess the requirements for clinical services.

Adult↗

[Fertilization in vitro. A review over the medical indications and suggestion to unified guidelines for public fertility clinics in Denmark].

Medical indications for in vitro fertilization and embryo transfer (IVF-ET) internationally and in Denmark are reviewed. Reports from large international centres document that tubal infertility, unexplained infertility, endometriosis and male infertility are equally good indications for IVF. Traditionally, tubal infertility has been the only medical indication qualifying for IVF treatment within the National Health Service in Denmark. Thus, in this country, couples with unexplained and male infertility and with endometriosis have to pay up to 25,000 D.Kr. per IVF-ET treatment in private fertility clinics. Since there is no scientific basis for this discrimination, it is urged that the present rules are changed, so that couples with unexplained and male infertility and endometriosis are also allowed IVF treatment free of charge in the public fertility clinics.

Denmark↗

Application of in-vitro fertilization in (almost) fertile couples should, and can, be avoided.

In-vitro fertilization is a successful treatment for infertile couples. However, in a minority of cases it can be dangerous, both for mother and child. IVF should therefore be avoided in (almost) fertile couples. A simple prognostic model makes it possible to distinguish couples with a good chance of conceiving spontaneously from those who deserve treatment in due course. Use of this model should enable IVF to be avoided in (almost) fertile couples.

Fertilization in Vitro↗

Non-functional fertility genes in humans: contributory factors in reduced male fertility?

Many of the mammalian sperm surface proteins that have been characterized in recent years have been implicated in sperm--egg interactions and subsequent fertilization. In particular, several members of the MDC protein family, most notably fertilin alpha, fertilin beta and cyritestin (also known as tMDC I), play an important role in sperm--egg interactions in rodents. In light of current data, it is proposed that many of these sperm proteins act co-operatively, and that the concerted effects of several proteins leads to 'maximum fertilizing ability', but that individual proteins are functionally redundant and are therefore not essential. Nevertheless, the co-operative nature of these interactions means that loss of individual proteins might lead to a concomitant reduction in fertilizing ability, a proposal that is supported by our recent finding of non-functional fertilin alpha and tMDC I genes in humans.

Journal Article↗

Modelling multiple ovulation, fertilization, and embryo loss in human fertility studies.

Models of human fertility that incorporate information on timing of intercourse have assumed that a single ovum is released each menstrual cycle. These models are misspecified if two or more viable ova are sometimes released in a single cycle, which is known to occur in dizygotic twin pregnancies. In this paper, we propose a model for multiple ovulation in humans. We assume that the unobservable number of viable ova in each cycle follows a multinomial distribution. Successful fertilization of each ovum depends on the ability of the cycle to support a pregnancy and on the aggregate of a set of unobservable Bernoulli trials representing the fertilizing effects of intercourse on various days. Our model accommodates general covariate effects, allows for heterogeneity among couples, and accounts for a sterile subpopulation of couples. Information on early detection of pregnancy can be incorporated to estimate the probability of embryo loss. We outline a Markov chain Monte Carlo algorithm for estimation of the posterior distributions of the parameters. The methods are applied to data from a North Carolina pregnancy study, and applications to studies of assisted reproduction are described.

Journal Article↗