Long-term effects of delayed parenthood

The present study aims to define, characterize and compare the long- term effects on offspring of delayed parenthood. Data published so far on this topic show that maternal and paternal ageing may affect offspring by different mechanisms. Delayed motherhood is characterized by increased probability of obstetric complications and/or fetal and perinatal problems which, in turn, may increase the risks of mortality and morbidity in newborns and later life. Furthermore, maternal ageing is distinguished by a decreased ratio of male to female infants and higher odds of conceiving a trisomic child and/or an individual suffering from mitochondrial DNA disorders. In contrast, delayed fatherhood is associated with higher risks of conceiving an individual suffering from new inheritable-mutation disorders. The different pattern of disease in offspring associated with maternal and paternal ageing may be explained, among other factors, by the fact that (i) oocytes of middle-aged women may suffer oxidative stress because their mitochondria produce higher amounts of reactive oxygen species; (ii) diplotene oocytes and to a lesser extent metaphase I and II oocytes have an efficient DNA repair system which is essentially independent of maternal age; and (iii) mitochondria are transmitted to the next generation along the matrilineal line. Moreover, (i) the activities of antioxidant enzymes within the seminal plasma and spermatozoa from older men may be reduced and so spermatozoa may be more vulnerable to mutational changes than spermatozoa from younger men; and (ii) late spermatids, and immature and mature spermatozoa do not have a DNA repair system.      

Gender preferences and demand for preconception sex selection: a survey among pregnant women in Pakistan

BACKGROUND: In its recent report 'Human Reproductive Technologies and the Law', the House of Commons' Select Committee on Science and Technology called for greater efforts to establish the potential demographic impact of sex selection across all sectors of UK society. Given the well-known preference for boys over girls among some communities, there is concern that a readily available service for social sex selection may upset the balance of the sexes. Of particular interest are the gender preferences and the demand for sex selection among Pakistanis. METHODS: We conducted a social survey on gender preferences and potential demand for preconception sex selection among 301 pregnant women in Karachi, Pakistan, using a self-report questionnaire consisting of 14 questions. RESULTS: About 41.5% wish to have a family with an equal number of boys and girls; 3.3% would like to have only boys, 1.0% only girls, 27.6% more boys than girls and 4.3% more girls than boys, and 22.3% stated that they do not care about the sex composition of their family. Whereas 6.3% could imagine employing cytometric sperm separation for social sex selection, 76.1% could not and 17.6% were undecided. About 27.2% felt that social sex selection ought to be legal, 48.8% thought it ought to be illegal and 23.9% were undecided. CONCLUSIONS: Although Pakistani women do show a statistically significant preference for boys over girls, the number of women willing to subject themselves to cytometric sperm separation appears to be too small to cause a severe imbalance of the sexes. However, further research among British citizens of Pakistani origin is needed to establish whether sex selection poses a serious threat to the sex ratio of UK communities.     

The influence of donated gametes on the incidence of hypertensive disorders of pregnancy.

Pregnancies achieved from oocyte, sperm or embryo donation are unique, since they have resulted from donor gametes that are immunologically foreign to the mother. Thus, studying the obstetric outcome of such pregnancies may shed some light on the pathophysiology of preeclampsia, particularly in women conceiving with donated embryos, since the entire fetal genome is allogenic in these pregnancies. In this retrospective cohort study, a total of 144 women were studied. Of these, 72 were infertility patients who had conceived as a result of sperm, ovum or embryo donation and the other 72 women were age- and parity-matched control patients who became pregnant with their own gametes, either spontaneously, or following intrauterine insemination with their partner's spermatozoa. Study patients were divided into three groups depending on the origin of the donated gametes. Group 1 consisted of pregnancies achieved by intrauterine insemination with washed donor spermatozoa (n = 33). Group 2 included women who conceived using donated oocytes (n = 27) and group 3 consisted of women who conceived as a result of embryo donation (n = 12). The incidence of pregnancy-induced hypertension in the donated gametes study group was 12.5% (9/72) compared with 2.8% (2/72) in the control group. In addition, pre-eclampsia was diagnosed in 18.1% (13/72) of the donated gametes study group compared to 1.4% (1/72) in the age- and parity-matched controls. The increased incidence of gestational hypertension in pregnancies resulting from donated gametes gives evidence for a maternal genetic component, with an equally strong fetal influence, in the complicated aetiology of gestational hypertension, and pre-eclampsia in particular.     

Endometriosis affects sperm-endosalpingeal interactions

BACKGROUND: The interaction between spermatozoa and the epithelium of the isthmic region of the uterine tube is thought to be an important part of the mechanisms of sperm transport to the site of fertilization and in preparing them for fertilization. However, it is unclear whether a dysfunction of this mechanism may contribute to subfertility in some individuals. METHODS: The sperm-binding characteristics of the epithelium from the uterine tubes of three groups of women were examined: (i) eight with pelvic endometriosis (not involving the uterine tubes); (ii) five women who had been receiving zoladex injections to control their symptoms; and (iii) as controls 10 women undergoing an elective procedure for benign gynaecological problems but with no other pathology of the reproductive tract. RESULTS: Significantly more spermatozoa bound per unit area to the ampullary epithelium of the uterine tubes taken from women with a previous diagnosis of endometriosis. CONCLUSIONS: These findings suggest that the characteristics of sperm binding to tubal epithelium may be disrupted in women with a gynaecological pathology such as endometriosis. It is suggested that this may have the potential to interfere with the availability of freely motile spermatozoa, of the appropriate physiological status, to take part in fertilization. This may be a newly described mechanism by which endometriosis can cause infertility.     

Sex predetermination and the ethics of sex selection

At present there appear to be two main categories of problems involved in the ethics of sex selection. The first has to do with the status of the embryo, and the second has to do with the social consequences of making sex selection widely available. However, these may not be the only issues. There is growing evidence from evolutionary psychology and biology, which suggests that the sex of the offspring in mammals may not, after all, be a matter of chance. Instead, sex allocation in mammals may be the result of a finely tuned adaptive process involving the current suitability of a mother to conceive an offspring of a particular sex. If so, we need to know more about this process before embarking on a social policy that could have disadvantageous outcomes for children, their parents and society as a whole.     

Psychosocial adjustment during pregnancy for older couples conceiving through assisted reproductive technology

BACKGROUND: The trend to older maternal age at first birth is well established in Western countries and biological risk factors, particularly declining fertility, are well documented. Less is known, however, about the psychosocial well-being of older first time parents. This study explores differences in psychosocial adjustment during pregnancy in older (maternal age >or= 38 years) and younger (maternal age < 35 years) couples after assisted reproductive technology (ART) conception. METHODS: Questionnaire data were collected from a consecutive cohort of pregnant nulliparous women and their partners recruited over a 12-month period from ART clinics in Sydney, Australia. RESULTS: There were more similarities than differences when comparing older and younger couples. Older couples took longer to conceive and were more likely to use donor eggs. Older pregnant women scored higher on a measure of psychological hardiness/resilience and reported a lower identification with motherhood compared with younger pregnant women. Older men differed only in reporting a less satisfying social orientation during pregnancy (lower satisfaction with sex life, relationship with partner and social life). CONCLUSIONS: Findings do not indicate problematic adjustment during pregnancy in older couples, but differences found need further investigation using larger samples and prospective designs.     

Maternal lead exposure and the secondary sex ratio

BACKGROUND: A reduction in the secondary sex ratio may be associated with exposure to environmental toxicants. Little data exists relating this outcome to lead exposure, a well-known reproductive toxicant. METHODS: We studied 1980 women having singleton births from 1994 to 1995 and from 1997 to 2001 who participated in a cohort study of lead exposure and infant outcomes in Mexico City. Levels of lead were measured in maternal and cord blood using graphite furnace atomic absorption spectroscopy, and levels of lead in maternal patella and tibia bone (a reflection of cumulative exposure) were measured using noninvasive K-X-ray fluorescence measurements. Using logistic regression models, we evaluated the relations of these measures to secondary sex ratio in the offspring, adjusting for maternal age, parity and year of infants' birth. RESULTS: We found no consistent association between any of the lead measures and secondary sex ratio. Results were unchanged when we adjusted for infants' year of birth, maternal age and parity. CONCLUSIONS: Despite a large sample size and the use of sensitive biomarkers, we did not find evidence that maternal and fetal lead exposure is associated with a lower secondary sex ratio among newborns.     

Meiotic behaviour of the sex chromosomes in three patients with sex chromosome anomalies (47,XXY, mosaic 46,XY/47,XXY and 47,XYY) assessed by fluorescence in-situ hybridization

Meiotic studies using multicolour fluorescent in-situ hybridization (FISH) and chromosome painting were carried out in three patients with sex chromosome anomalies (47,XXY; 46,XY/47,XXY and 47,XYY). In the two patients with Klinefelter syndrome, although variable percentages of XXY cells (88.5 and 28.3%) could be found in the pre-meiotic stages, none of the abnormal cells entered meiosis, and all pachytenes were XY. However, the abnormal testicular environment of these patients probably resulted in meiotic I non-disjunction, and a certain proportion of post-reductional cells were XY (18.3 and 1.7%). The fact that none of the spermatozoa were XY also suggests the existence of an arrest at the secondary spermatocyte or the spermatid level. In the XYY patient, most (95.9%) premeiotic cells were XYY. The percentage of XYY pachytenes was 57.9%. The sex chromosomes were either in close proximity (XYY) or the X chromosome was separated from the two Ys (X + YY). A high proportion (42.1%) of post-reductional germ cells were XY. However, only 0.11% of spermatozoa were disomic for the sex chromosomes. In this case, the data suggest the existence of an arrest of the abnormal cells at the primary and the secondary spermatocyte or the spermatid level, giving rise to the continuous elimination of abnormal cells in the germ-cell line along spermatogenesis. The fact that the proportion of diploid spermatozoa was only increased in one of the three cases (XXY) is also suggestive of an arrest of the abnormal cell lines in these patients. The two apparently non-mosaic patients were, in fact, germ-cell mosaics. This suggests that the cytogenetic criteria used to define non-mosaic patients may be inadequate; thus, the risk of intracytoplasmic sperm injection in apparently non-mosaics may be lower than expected.     

Fluorescence in-situ hybridization of sex chromosomes in spermatozoa and spare preimplantation embryos of a Klinefelter 46,XY/47,XXY male

It has been suggested recently that 47,XXY germ cells are able to progress through meiosis to produce hyperhaploid spermatozoa. We report on a 46,XY/47,XXY Klinefelter patient whose spermatozoa were recovered from the ejaculate and used for intracytoplasmic sperm injection (ICSI). Fluorescence in-situ hybridization (FISH) analysis of the patient's spermatozoa and of spare preimplantation embryos with DNA probes specific for chromosomes X, Y and 18 revealed sex chromosome hyperploidy in 3.9% of the sperm nuclei analysed (2.23% XY18, 1.12% XX18, 0.56% YY18), while only three out of 10 spare embryos analysed were normal for chromosomes tested. The abnormalities included two diploid mosaic embryos with the majority of the blastomeres normal for the chromosomes tested, and five embryos with mostly abnormal blastomeres and chaotic chromosome X, Y and 18 patterns. None of the embryos analysed showed a XXY1818 or XXX1818 chromosome complement. The frequency of sex chromosome hyperploidy in the spermatozoa of the mosaic Klinefelter patient was higher than the mean reported for karyotypically normal males, supporting the hypothesis that 47,XXY germ cells are able to complete meiosis and produce aneuploid spermatozoa. However, most of the spermatozoa analysed were normal for sex chromosomes, and ICSI of the patient's spermatozoa did not result in a spare embryo with a uniform 47,XXY or 47,XXX chromosome complement. Instead, fertilization produced a high percentage of mosaic embryos with chaotic chromosome arrangements.     

Morphologically normal spermatozoa of patients with secretory oligo-astheno-teratozoospermia have an increased aneuploidy rate

BACKGROUND: Normal morphology is a major criterion for selecting spermatozoa to be injected. Given that teratozoospermia is one of the most critical parameters associated with sperm aneuploidy, the purpose of this study was to evaluate the aneuploidy rate of morphologically normal spermatozoa of patients with oligo-astheno-teratozoospermia (OAT). METHODS: Ten patients with secretory OAT and six age-matched normozoospermic men with a normal karyotype were enrolled. After assignment to normal or abnormal category, the location of each spermatozoon was recorded using an electronic microstage locator. Slides were then subjected to triple-colour fluorescence in situ hybridization for chromosomes X, Y and 12. RESULTS: OAT patients had a lower number of morphologically normal and abnormal spermatozoa carrying the X chromosome, compared with normozoospermic men. They also exhibited increased XY and XX disomy rates. Morphologically abnormal spermatozoa from normozoospermic men also had an increased XX disomy rate compared with normally shaped spermatozoa obtained from the same men. The total sperm aneuploidy rate of morphologically abnormal spermatozoa of normozoospermic men was 4.4-fold higher than that of spermatozoa with normal morphology. The total aneuploidy rates of spermatozoa with normal or abnormal head shape from OAT patients were similar to each other and to that of abnormally shaped spermatozoa from normozoospermic men, but they were higher than the rate found in normally shaped spermatozoa of normal men. CONCLUSIONS: Normally shaped spermatozoa of OAT patients have an increased aneuploidy rate.     

Identification of functional alpha2- and beta-adrenergic receptors in mammalian spermatozoa

BACKGROUND: A recent study of several compounds, structurally related to amphetamine, provided evidence that mammalian spermatozoa might have adrenergic receptors able to regulate cAMP production. The present study investigated this possibility using physiological and immunochemical analyses of mouse and human spermatozoa. METHODS: Antibodies specific for different receptor subtypes were used for Western blotting of mouse and human sperm lysates and for immunocytochemical evaluation of whole mouse and human spermatozoa. Uncapacitated and capacitated mouse spermatozoa were incubated with specific agonists and antagonists for alpha2-, beta1-, beta2- and beta3-adrenergic receptors for approximately 35 min and then assessed using chlortetracycline (CTC) fluorescence. RESULTS: Western blotting revealed proteins of the correct size for all these receptors; immunolocalization indicated their presence on the head, especially acrosomal and neck regions, and flagellum of both mouse and human spermatozoa. CTC results indicated significant responses to agonists for all of the beta-receptors in uncapacitated cells, with agonist effectiveness being beta1 > beta2 > beta3; relevant antagonists blocked responses. In contrast, an agonist and antagonist for alpha2-receptors acted only on capacitated spermatozoa. CONCLUSION: These experiments provide the first good evidence that mammalian spermatozoa have both beta-adrenergic receptors, known to stimulate cAMP production by membrane-associated adenylyl cyclases (mACs), and alpha2-adrenergic receptors, known to inhibit cAMP production by mACs. Responses are capacitation state dependent and provide a mechanism for inhibiting spontaneous acrosome reactions and helping to maintain fertilizing ability. These results suggest that the use of amphetamine-related compounds, either for medical or for social reasons, might have an unexpected positive impact on fertility.     

Sex Differences in Genetic Risk for Dementia

We used two Swedish twin samples to test whether women are at greater risk than men of developing dementia and whether there are sex differences in mechanisms underlying dementia and cognitive dysfunction. Dementia analyses found no sex differences in incidence of dementia or Alzheimer's disease among initially intact participants followed longitudinally. Twin analyses indicated a substantial genetic influence on liability to incident dementia. Although sex differences in model parameters were not statistically significant, for women but not men an equally attractive model included genetic influence due to both additive effects and dominance or epistasis. In the cognitive dysfunction analyses, results from a sex limitation model raise the possibility that either different genes or different environments have a role for men and women. We conclude that women are not at higher risk of developing dementia, but there is a hint that different genetic processes may be involved for women than for men.     

A human-mouse hybridoma producing monoclonal antibody against human sperm coating antigen.

Since anti-sperm antibodies were first discovered in the sera of women, the relationship of these antibodies to sterility has been studied by many investigators. In order to determine the antigens of spermatozoa responsible for raising antibodies to spermatozoa in humans, many studies have been carried out by purifying human spermatozoa cell membrane and seminal plasma components. Since it was found that the purification was difficult by physiochemical procedures, the immunoaffinity chromatography bound monoclonal antibody (Mab) to spermatozoa antigens was attempted for this purpose. The establishment of hybridomas producing Mabs to human seminal plasma and human spermatozoa was reported by Shigeta et al. (1980), Isojima, Koyoma & Fujiwara (1982), Lee et al. (1982) and Isahakia & Alexander (1984). The ordinary approaches to obtain the Mabs consisted of xenogenic immunization with human semen and cell fusion of immunized spleen cells with mouse myeloma cells. However, the antigenic epitopes of human spermatozoa, which induced antibody production, are xenogenic for the mouse, and therefore there is a possibility that there is a difference in recognized antigenic epitopes in humans as isotypic and in mice as xenogenic. In order to study these antigenic epitopes, which correspond to antibodies against spermatozoa in women, the establishment of human-mouse hybridomas, which produced anti-semen antibodies as produced in sterile women, became essential. In these studies, we used recently developed cell fusion techniques to fuse immunized human peripheral lymphocytes with mouse myeloma cells.     

Sperm treatment with extracellular ATP increases fertilization rates in in-vitro fertilization for male factor infertility

Previous work from our laboratory has revealed that extracellular ATP is a rapid and potent activator of human sperm acrosome reaction and fertilizing ability. In the present study, we assessed the effects of in-vitro sperm incubation with ATP on fertilization and embryo development in couples undergoing in-vitro fertilization (IVF) for male factor infertility. Oocytes from 22 women undergoing ovulation induction were divided in two groups and inseminated in vitro either with selected spermatozoa from the corresponding partner suffering from male factor infertility pre-incubated with ATP (2.5 mM) for 1 h, or with spermatozoa incubated with 0.9% NaCl solution (control group). After insemination, fertilization was assessed by the presence of pronuclei and then by embryo cleavage. The fertilization rate in the group of oocytes inseminated with ATP-treated spermatozoa improved significantly with respect to the control group (65.7 versus 42.5%, P < 0.01). No significant differences were observed in embryo cleavage and embryo quality. Embryos from both treated and control groups were transferred together in 20 transfer procedures, and in two couples fertilization was not obtained. Nine pregnancies occurred: one biochemical, one miscarriage, and seven patients delivered 9 healthy babies. Two pregnancies were twin with an overall pregnancy rate of 40.9% per cycle and of 45% per transfer. In conclusion, the results of the present study demonstrate that, in humans, extracellular ATP induces a significant increase of sperm fertilizing potential, as these findings are a rationale for the use of ATP for in-vitro treatment of human spermatozoa during IVF.     

Regional binding of human anti-sperm antibodies assessed by indirect immunofluorescence

Indirect immunofluorescence (IIF) can be a powerful tool for determining the site on spermatozoa to which antibodies bind. Human sera that contain anti-sperm antibodies are often of low titre, and may contain antibodies directed against both intracellular and surface antigens. We have developed an IIF protocol that helps to distinguish intracellular from surface labelling. The two types of labelling were differentiated by exposing the spermatozoa to Hoechst 33258, a nuclear stain of low membrane permeability, to tag the spermatozoa that had disrupted membranes. Surface labelling detected in this fashion was patchy. It was much more uniform if the spermatozoa were fixed in paraformaldehyde, or if a univalent, Fab fragment was used as the second antibody. Thus, it is likely that most of the patchy appearance is due to the bivalent second antibody cross-linking mobile antigen-antibody complexes. For some sera, patching was so pronounced that it appeared to remove the label from portions of the sperm surface, giving a misleading picture of the regions to which the antibodies were directed. Fourteen sera were used in IIF and none of them labelled spermatozoa solely on the head or on the tail.     

The effect of in-vitro ageing on mouse sperm chromosomes

In-vitro ageing has long been suspected to affect adverselythe ability of spermatozoa to fertilize and produce viable zygotes.A comparison of the first cleavage chromosome complement of824 mouse embryos fertilized with fresh spermatozoa and 656embryos fertilized with spermatozoa aged for 12, 24 or 48 his reported herein. The chromosome analysis of first-cleavageembryos allows us to study directly the paternal and maternalchromosome complements which contribute to the embryo. Bothchromosome clusters remain separate when an antimitotic agentis used to prevent metaphase synchronization, allowing identificationof maternal and paternal chromosomes. We show that after spermageing, there is a decrease in the fertilization rate from 75%in the controls to 57.5% (12 h of ageing), 63.5% (24 h of ageing)and 4.4% (48 h of ageinaj. Simultaneously, the level of chromosomestructural abnormalities increases from 1.3% in the controlsto 16.5% after 12 h of ageing, 18.8% after 24 h of ageing and59% after 48 h of ageing. The incidence of aneuploidy and polyploidyis not affected by ageing of the spermatozoa. Most of the structuralabnormalities are paternal in origin and are presumably inducedby the ageing of spermatozoa.     

Gender reassignment and assisted reproduction: present and future reproductive options for transsexual people

Transsexual people who want transition to their desired gender have to undergo hormonal and surgical treatments, which lead to irreversible loss of their reproductive potential. This paper argues that transsexual people should be offered the same options as any person that risks losing their germ cells because of treatment for a malignant disease. Indeed, transsexual women (male-to-female transsexual patients) may be given the option to store spermatozoa before they start hormonal therapy, so that their gametes may be used in future relationships. This may be especially important for the many transsexual women who identify as lesbians after their transition. Conversely, transsexual men (female-to-male transsexual patients) may be offered storage of oocytes or ovarian tissue, possibly obtained at the time of their oophorectomy. Current technology offers transsexual people the possibility to obtain children who are genetically their own in their future relationships and the option of gamete banking should therefore be discussed before starting hormonal and surgical reassignment treatment. This is particularly important for transsexual people who are diagnosed and treated at a young age.     

Intrauterine donor insemination in single women and lesbian couples: a comparative study of pregnancy rates

The outcome of intrauterine donor insemination (IUI-DI) with frozen spermatozoa was analysed retrospectively in 675 cycles in single women (n = 122; 536 cycles) and lesbian (n = 35; 139 cycles) couples. The lesbian patients were younger at the initiation of treatment (mean 34.5 years; range 26-44) than the single women (mean 38.5; range 29-47) (P = 0.005). Clinical pregnancy rate was 36% in single women and 57% in lesbians (P < 0.05), the cumulative pregnancy rate after six cycles being 47% and 70% respectively, although the outcome was similar when related to age. The miscarriage rate was higher (35%) in single women than in lesbians (15%; P < 0.05), the rate being independent of maternal age. There were no apparent differences seen between the two groups with respect to the possible effect of parity, duration of infertility, causes of infertility and type of treatment at initiation of treatment; the sole exception was that the age of lesbian women was statistically significantly younger than that of single women (P < 0.005). When corrected for age, the pregnancy rates and complications were lower and higher respectively in single women but these differences did not reach statistical significance. However, the disparity between the treatment outcomes of single women and lesbian patients of similar ages may also reflect the fact that single women are likely to have failed to conceive for a period of time prior to referral to a specialist centre for treatment.     

The potential shortcomings of measuring hyperactivated motility by computer-aided sperm analysis when sperm motion is multiphasic

This paper was written from the standpoint that computer-aidedsperm analysis (CASA) instruments, which capture a 'snapshot'of sperm trajectories in order to generate their data, may providea poor measure of hyperactivated motility in a sperm populationwhere hyperactivation is multiphasic in nature. To illustratethis point, a series of theoretical sperm populations were constructedwhich varied subtly but significantly in the nature of the hyperactivatedbehaviour expressed by spermatozoa. The parameters which weremanipulated were: (I) the number of hyperactivated phases exhibitedwithin a given period of time; (ii) the duration of these phases;and (iii) proportion of spermatozoa within the population whichexhibited hyperactivated phase. Thee populations were then subjectto an analysis in which snapshots of sperm motion were examinedto determine the percentage of hyperactivated spermatozoa forthat population. The results indicated that whilst this snapshotapproach to quantifying hyperactivation could provide a figurefor the percentage of hyperactivated spermatozoa for that population.The results indicated that whilst this snapshot approach toquantifying hyperactivation could provide a figure for the percentageof hyperactivated spermatozoa within the sample window, thisoften inaccurately described the underlying behaviour of thepopulation. Since there is very likely to be a significant amountof biological information contained within the nature of multiphasicbehaviour, this paper has argued that this aspect of snapshotanalysis is one which requires serious consideration by CASAmanufacturers and medical researchers.     

Trait dominance is associated with vascular cardiovascular responses,and attenuated habituation,to social stress

Both exaggerated and diminished levels of cardiovascular reactivity have been associated with cardiovascular ill health. Dysregulation of hemodynamic mechanisms which control cardiovascular functioning may account for some individual differences in health outcomes. Trait dominance has also been associated with poor cardiovascular health in studies of humans and animals. The current study investigated the relationship between trait dominance and cardiovascular habituation to repeated social stress in humans.