A method of computing period rates of spinsterhood and childlessness from census data applied to the United States.
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Adult↗
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Results for “Reproductive Behavior--changes”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Experiential and hormonal conditions affect squab-egg choice in ring doves (Streptopelia risoria).
Noncycling, progesterone-injected, experienced male ring doves prefer eggs to squabs in a simultaneous squab-egg choice test, while experienced male doves injected with both progesterone and prolactin prefer squabs to eggs. When exogenous prolactin is administered to either naive or experienced male ring doves during the early phase of a normal incubation cycle, squab choice is significantly increased. Squab choice is also significantly increased in incubating doves by 24 hr of exposure to a squab in the home nest. This effect is greater in naive than in experienced doves. Squabs introduced during late incubation have more of a positive effect on squab choice than when introduced during early incubation. It is concluded that intracyclic experience organizes successive behavioral changes within a reproductive cycle and that naive doves are more affected by some changes in intracyclic events than are experienced doves.
Animals↗
School-based programs to reduce sexual risk-taking behaviors.
This article reviews the major approaches implemented during the last two decades to reduce sexual risk-taking behaviors, examines their evidence for success, and provides several recommendations for effective programs and program evaluations. This article does not discuss more broad-based sexuality education programs which address sexuality in a broader context. Instead, this article focuses primarily on programs that educators believed would reduce unprotected sexual intercourse.
Adolescent↗
Psychotropic drugs as behavioral teratogens.
Three psychotropic drugs were administered to pregnant rats and were then evaluated for their behavioral and reproductive effects in the offspring. Control rats received either saline or vitamin A. Prochlorperazine had the most disruptive effects on reproduction and growth, but had the least effect on behavior. Propoxyphene had no apparent effects on reproduction or growth, but produced a variety of behavioral changes. Fenfluramine was intermediate in its effects on reproduction and growth and had behavioral effects that were revealed in tests of preweaning development. The data suggest that systematic tests of behavior add important information to evaluations of reproductive toxicity that cannot, at present, be obtained by other means.
Animals↗
Behaviour change in HIV infected subjects following health education.
A total of 85 HIV seropositive subjects among consecutive new registrants in the STD Department were given health education measures directed to avoiding high risk behaviours and also the events with a high potential for transmission of infection. The emphasis was on the use of condoms, discontinuing promiscuity, abstaining from homosexual acts and avoidance of pregnancy and advice against marriage for those contemplating it. The Health Education Programme was delivered individually to each subject over two or three sessions, each lasting for 30 to 45 min. At the time of follow up (one to 24 months) 42 per cent of subjects had become non-promiscuous. There was a good compliance on advice against marriage and pregnancy. Seven infants born during the follow up period were seronegative. The use of condom was not found to be acceptable. The prostitutes comprised the most resistant group to education. Among the factors that influenced the behaviour change favourably was the absence of earlier STD or a short duration of the current STD. Literacy, marital status, awareness of AIDS did not influence the outcome of education. The study demonstrated the feasibility of health education at individual level in the clinical setting of an STD Department. A longer follow-up may indicate the sustainability of behaviour change in the subjects.
Adult↗
An ethological view of human adolescence.
In modern times the essential "normality" of adolescence has been acknowledged. With its pan-cultural and functional perspective, ethology is in a position to elaborate a description of normal human adolescence. Ethologists attempt to elucidate four interrelated aspects of a given behavior: its survival function, evolution, development, and elicitation by internal and external factors. The basic research strategy is two-fold: to identify biologically based, or evolved, behaviors (chiefly by controlling for the effects of experience and seeing if a core of evolved behavior remains); and to discover their functions by isolating the necessary and sufficient ecological conditions for their evolution. Applying this evolutionary analysis to human adolescence, we find that two developments seem to be basic: reproductive maturation and gaining independence from parents. The remainder of the article is an interpretation of various behavioral, morphological, and cultural data in accordance with these two developmental functions. Puberty seems to be timed so as to promote these functions most effectively. Pubertal changes parallel somatic growth and are delayed by poor nutrition, disease, and psychological stress--patterns consistent with functional considerations. The influence of natural selection on the sequencing of pubertal events is also emphasized. The role of pubertal hormones in altering behavior as well as morphology is illustrated. The adolescent gains independence from his parents by means of maturation and sex differentiation. Males become specialized for vigorous exertion, and females for work near the settlement--although considerable overlap in morphological and behavioral tendencies exists between the sexes. Various examples of sex differentiation demonstrates how morphological, behavioral, and cultural factors complement each other. Adolescent initiation rites help channel boys and girls into appropriate adult roles, teach respect for one's culture, and favor the fittest individuals. Hopi rites of passage are described as an example. Reproductive maturation likewise involves adaptive morphological and behavioral changes that are reinforced by cultural mores. Males rely on intimidation more than females, in order to dominate other males and attract females; contrariwise, females employ an endearment strategy more than males do. Many sex differences in human reproductive behavior can be explained with reference to man's parental behavior pattern. These include the male's greater aggressiveness, the preponderance of polygyny over polyandry, and differences in the antecedents of jealousy. Lastly, the need for an ethological understanding of adolescence is underscored as promising to offer a useful perspective on the problems of U.S. youth.
Adolescent↗
Changes in sexual behavior among women in studies evaluating the dapivirine vaginal ring for HIV prevention.
BACKGROUND: Access to novel HIV prevention technologies often raise concerns of risk compensation. This analysis examined changes in the sexual behaviors of MTN 020/ASPIRE participants, a placebo controlled randomized control trial, who subsequently enrolled in MTN-025/HOPE, an open-label extension using the dapivirine vaginal ring. METHODS: Both studies enrolled healthy, sexually active, HIV-negative women from Malawi, South Africa, Uganda and Zimbabwe. Longitudinal data on participants' sexual behaviors, specifically sex with a nonprimary partner (past 3 months), and use of male or female condoms at the last vaginal sex act were compared between ASPIRE and HOPE. Conditional and mixed ordinal logistic regression models evaluated associations between study and sexual behaviors at enrollment, and quarterly over the first 12 months. RESULTS: Of the 2629 individuals enrolled in ASPIRE, 1456 (55%) participated in HOPE. At enrollment, the proportion of participants who reported sex with a nonprimary partner and condom use at last vaginal sex act did not differ by study. Across all quarterly follow-up visits, sex with a nonprimary partner was more common in HOPE (13.9-18.7%) than ASPIRE (10.7-12.6%); adjusted OR 1.47, 95% CI 1.24-1.75, P < 0.001. There was no difference in condom use at the last vaginal act across all quarterly follow-up visits between ASPIRE (36.5-42.7%) and HOPE (43.6-46.7%); adjusted OR 1.05, 95% CI 0.94-1.18. CONCLUSION: More women reported sex with nonprimary partners in HOPE, with little change in condom use over time between the two studies. Understanding behavior changes during PrEP use allows for tailored, holistic reproductive health programming.
Humans↗
The changing pattern of sexually transmitted diseases in adolescents.
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Adolescent↗
Captivity affects behavioral physiology: plasticity in signaling sexual identity.
Little is known about the link between captivity, physiology, and behavior in wild-caught vertebrates. Anecdotal evidence suggests that hormonal changes are responsible for behavioral changes in wild animals brought into captivity. Studying the effects of captivity on reproduction is hampered because wild animals often fail to exhibit sexual behavior under captive conditions. In weakly discharging electric fish, field studies have reported sex differences in electric organ discharges which are rarely seen in the laboratory. I now report the results of a series of laboratory investigations which show that Gnathonemus petersii exhibits seasonal, hormone-dependent, phase-specific sex differences in electric organ discharges. Captivity dramatically alters and may even reverse these sex differences as a result of rapid changes in endogenous plasma hormone levels. These findings have broad implications for research on animal physiology and behavior performed in laboratory settings.
Androgens↗
The social construction of premenstrual syndrome.
In 1931 a physician coined the term Premenstrual Tension, thereby commencing an extensive biomedical inquiry into the relationship between women's menstrual cycle and the occurrence of physical, emotional and behavioral changes. However, despite 58 years of scientific research, fundamental questions remain unanswered. For example, there is still no consensus on the definition of PMS. This, in turn, has led to disagreement among researchers about which medical specialty is best suited for diagnosing and treating PMS. Is PMS a disease whose pathology is best understood by physicians in reproductive medicine or in psychiatry? This paper argues that the inconclusiveness surrounding PMS is symptomatic of the persistence of cultural beliefs in the production (and reproduction) of medical knowledge. The roots of these cultural beliefs and their 'naturalness' in the context of Western ideas about reason, rationality and women are explored in the first section. The second section discusses the ubiquity of these same cultural beliefs in contemporary scientific research of PMS and in the controversy surrounding the proposed psychiatric diagnostic category of Late Luteal Phase Dysphoric Disorder (LLPDD). Finally, a new, anthropologically and sociologically informed approach to understanding the phenomenon of PMS is suggested.
Attitude to Health↗
Adolescent pregnancy: an interpersonal skill training approach to prevention.
The research literature reports numerous negative consequences of adolescent pregnancy. Unfortunately, contemporary approaches to preventing teenage pregnancies have been largely unsuccessful. Recent evidence, however, suggests that interpersonal communication skill training may represent an important step in helping adolescents deal with their sexual and contraceptive behavior. This describes a pilot study of an interpersonal skill training model for sexually active inner-city teenagers. Results show that this training model is a feasible and attractive approach to modifying the youths' communication patterns. Findings indicate that such training is a fruitful direction for future pregnancy prevention research with the adolescent target population.
Adolescent↗
The why, when and whether of condom use among female and male drug users.
Eight focus groups consisting of all male, all female and mixed male and female drug users were conducted to gain an in-depth understanding of beliefs and behavior regarding the use of family planning services and contraceptives, particularly condom use in an effort to reduce the perinatal transmission of HIV. While participants often supported the use of condoms because of STDs and AIDS, their unplanned pregnancies and STD histories indicated in-consistent use, depending on the partner and the circumstances. The vast majority of both men and women did not like to use condoms because it interfered with the spontaneity and pleasure of sexual relations, though women seemed more willing to use condoms than their partners. Participants varied in their knowledge about the benefits of using a condom, in how and when to put it on, in the associations they made between condom use and trust and commitment, in the type of partner and conditions under which they would use condoms and in their willingness to consider condom use as an integral part of their lives. Issues of trust, commitment and condom use did not seem to have been resolved in the drug using community, particularly among younger people who appeared to have more difficulty in negotiating condom use. Promoting the use of condoms needs to be considered as part of a larger, multifaceted behavior change effort.
Condoms↗
Daily variation of multiple behaviors in Aplysia fasciata: integration of feeding, reproduction, and locomotion.
Daily variations in feeding, reproductive behaviors, and activity level were examined under three conditions: (1) animals had access to food and mates; (2) there was access only to food; (3) neither food nor mates were present. Behaviors differed in amplitude of variations from their daily mean value. Egg-laying had the strongest tendency to be clustered. Amplitude of variations in courtship and swimming was larger than those of immobility, crawling, and feeding, while moving in place was the least clustered behavior. Changes in state affected the tendency to be clustered. When food and mates were present, amplitude of variations became progressively larger for immobility, moving in place, crawling, and swimming. Behaviors differed in the degree to which variations were patterned as a 1/day oscillation. Relatively little of the variability in crawling, moving in place, courtship, and egg-laying was due to a 1/day oscillation under any condition. By contrast, a large proportion of the variability of immobility, swimming, mating, and eating was modulated by a 1/day oscillation in at least one condition. The contribution of a 1/day oscillation to variability differed in the conditions examined. For immobility and swimming, when food and mates were present, the 1/day component of variability became smaller. By contrast, presence of mates led to an increase in the 1/day component of variability modulating feeding. Daily peaks of swimming and feeding were in phase with one another, and out of phase with mating and feeding. The ratio of locomotion to inactivity is constant, independent of change in external conditions. However, this ratio varied throughout the day. When food and mates were absent, variations of immobility and swimming were strongly related to variations in the inactivity ratio. When food and mates were added, this tendency decreased. The data suggest that daily variations in occurrence of behaviors can be accounted for by interactions between oscillators affecting Aplysia behavior and motivational variables. A 1/day oscillator has strong effects on mating, swimming, and immobility. The effect of the oscillator is modified by changes in motivational state.
Animals↗
Ectopic expression of sex peptide alters reproductive behavior of female D. melanogaster.
Sex peptide, a secreted component of the male accessory glands, has been shown to induce behavioral and physiological changes in mated Drosophila. We transformed flies with a hybrid gene containing an hsp70 promoter fused to a cDNA encoding sex peptide. Heat-induced ectopic expression of the peptide in transgenic virgin females altered their reproductive behavior, in the presence of courting males, to that observed in mated females. This demonstrates that the peptide is functional as expected. Time course studies revealed that the behavioral change appeared earlier than the stimulated ovulation. We have also introduced a modified sex peptide gene that is driven by the yp1 enhancer, conferring expression in adult females, and shown that these flies refuse mating constitutively in the presence of courting males and lay unfertilized eggs at the rate of mated females.
Animals↗
Human immunodeficiency virus/acquired immunodeficiency syndrome in pregnant women.
A pregnant woman experiences selective immunosuppression as a physiologic response to the presence of a genetically heterologous fetus. Case reports early in the acquired immunodeficiency syndrome (AIDS) epidemic suggested that adverse human immunodeficiency virus (HIV)-related clinical outcomes might be causally associated with pregnancy. A review of relevant published data indicates that: (1) Adverse clinical outcomes of pregnancy are common among HIV-infected pregnant women, but no studies to date have fully disentangled the many confounding factors. (2) HIV-related complications are common in pregnancy only among immunosuppressed (< 300 CD4+ cells/mm3) women. (3) The distinct effect of pregnancy on the expression of HIV infection cannot be evaluated in the absence of appropriately controlled observations. (4) Cofactors for perinatal transmission are poorly understood. (5) Research into the motives for reproductive decisions and behaviors is of critical importance for improving our health education and outreach efforts for high-risk women. (6) Adequate clinical treatment and prophylactic health care services must be made easily accessible and available to women at high risk of HIV disease. (7) Treatment with available antiviral and anti-Pneumocystis drugs is advisable for HIV-infected pregnant women with fewer than 300 to 350 CD4+ cells/mm3, though data to definitively guide therapeutic decision making are not available. (8) Large multicenter studies are needed to recruit patients and to retain them in sufficient numbers, allowing for better evaluation of the many variables determining clinical outcomes for HIV-infected mothers and their infants. The natural history of HIV in pregnant women must be studied to facilitate clinical decision making, and to design and implement interventions, including prevention (behavior change, vaccines) and treatment (chemotherapy, immunotherapy).
Acquired Immunodeficiency Syndrome↗
Changing patterns of adolescent sexual behavior: consequences for health and development.
Sexuality is a fundamental quality of human life, important for health, happiness, individual development, and indeed for the preservation of the human race. During the dynamic period of adolescence in which the passage from childhood to maturity takes place, sexuality takes on new dimensions; feelings become more intense, relationships become more complex, and the consequences of sexual behavior are radically altered. This not only affects the behavior of young people but also of those who interact with them, their families and peers, and those who work in the health, education, youth, social welfare, and other sectors. In the contemporary world the conditions of life for many young people have also changed, and with it patterns of sexual behavior. In general, earlier puberty, later marriage, a decline in the family leading to less control and more autonomy, and intense exposure to sexual stimuli via the mass media and travel across cultural boundaries have made pre-marital adolescent sexual activity more common. This has added to traditional problems of early marriage, newer problems of early pregnancy, childbirth, and induced abortion outside of marriage, sexually transmitted diseases, and human immunodeficiency syndrome infection leading to acquired immunodeficiency syndrome. But the work of the World Health Organization (WHO), along with many others in the field, strongly suggests that given appropriate information and services, trust and equity between the sexes, young people will behave responsibly and well. In this paper some of the findings from methods developed by WHO for research, training, advocacy, and evaluation, and findings in relation to patterns and determinants of sexual and reproductive health and development will be described, and future directions suggested.
Adolescent↗
Intrauterine infection of mice with St. Louis encephalitis virus: immunological, physiological, neurological, and behavioral effects on progeny.
Intravenous injection of pregnant mice with St. Louis encephalitis (SLE) virus at 8 days of gestation resulted in infection of the fetus. Progeny developed no antibody or tolerance to SLE virus since the viral antigen was cleared by maternal antibody before antibody-forming competence developed in the young. Temporary growth retardation was observed in a number of young at 3 weeks of age. After the initial setback the growth rate increased, indicating that early runting was due to an inability to adjust adequately to extrauterine life, which was subsequently overcome. In most other young there were no significant effects on growth, reproduction, or life expectancy. A few young died at or shortly after birth; in these, neurological changes ranging from gross defects such as encephaloceles and hydrocephalus to histological evidence of necrosis and congestion were observed. Neurologically related behavioral changes were detected by using the open field test and the rotating-rod test, which indicated neurological damage and memory impairment in the surviving intrauterinely infected animals.
Animals↗
Time and sex in the male mouse: temporal regulation of infanticide and parental behavior.
Infanticide is a violent but successful reproductive strategy found in many mammals, particularly rodents. In male house mice (Mus domesticus and M. musculus), the act of ejaculation provides a reliable neural signal for timing the birth of their offspring. However, a unique chronobiological aspect of this phenomenon is the extraordinary temporal latency that can occur between the stimulus (coital ejaculation) and its adaptive neural response (male mice cease killing pups and behave parentally toward them instead). Specifically, the inhibition of infanticide is often time delayed for many days after a male ejaculates, but virtually always occurs before or around the time his own sired offspring would be born 18-20 days later. Furthermore, infanticide spontaneously reemerges 50-60 days after mating. In CF-1 stock male mice this entire behavioral sequence is synchronized with the female's reproductive cycle, and occurs even in the total absence of social cues or changes in pituitary or gonadal hormones after mating. When entrained and mated at 22 h (light:dark 11:11) or 27 h (light:dark 13.5:13.5) T-cycles, photoperiodic cues appeared to synchronize this dramatic shift in behavior, because a sudden transition from pup killing to parenting was matched with the number of light/dark cycles experienced after ejaculation rather than the amount of real time experienced, suggesting a circadian timing link. Housing in constant light accelerated the postmating transition to parenting, whereas constant dark significantly delayed the transition to parenting, but still occurred by 3 weeks after mating. Most males tend to oscillate between infanticide and parental behavior for several days before locking in to constant parenting, regardless of lighting conditions. Variation in the time delay between ejaculation and the inhibition of infanticide was consistent within young individuals (< 10 months of age), but in older males (> 18 months of age) the time interval between ejaculation and parenting was significantly prolonged and attenuated. Another unique aspect of this phenomenon is that variation among individuals in their timing and response to light cues is correlated with phenotypic variation in sex steroid exposure during late fetal development. So far, no simple physiological explanation can account for the neural mechanism triggered by ejaculation that coordinates these time-delayed behavioral changes toward pups.
Animals↗