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PubMed1996

[Reproductive history of Chilean puerperal women hospitalized in a public hospital of the metropolitan region].

BACKGROUND: Maternal and infantile morbidity is closely related to the features of women's reproductive history. AIM: To study the reproductive behavior of women hospitalized due to labor or abortion in a public maternity of Metropolitan Santiago. SUBJECTS AND METHODS: One thousand women were interviewed about their reproductive behavior, 24 to 72 hours after pregnancy resolution. RESULTS: Ages of interviewed women ranged from 13 to 47 years old. Eighty seven percent had three children or less. The proportion of single women with a first pregnancy was 62% and decreased to 9.3% in those with a second pregnancy. At the first pregnancy, 1.3% of women were using contraceptives, notwithstanding that 27% did not want to become pregnant. Most women had a birth spacing of 24 to 59 months. There was a low number of stillbirths in this sample. CONCLUSIONS: This work shows that studied women have pregnancies at low risk ages and an adequate parity.

Adolescent↗
PubMed1986

The annual breeding cycle of the high-arctic Svalbard ptarmigan (Lagopus mutus hyperboreus).

Gonadal size, spermatogenesis, egg production, height of the supraorbital comb, moult, and plasma luteinizing hormone (LH) levels were measured during an annual cycle in wild Svalbard ptarmigans (Lagopus mutus hyperboreus). These birds live permanently at 77-81 degrees N where daylight is continuous from the beginning of April until mid September while the average ambient temperature is above freezing only between early June and mid September. The gonads and comb size began to enlarge in March coinciding with an increase in plasma LH, but sperm production and egg laying did not begin until the end of May and early June, respectively. This long lag between the onset of reproductive functions and the time of breeding reflects a slow rate of gonadal growth which may be caused by nonphotoperiodic, inhibitory input from the environment. Gonadal regression occurred in July and was associated with a steep decline in plasma LH levels indicating that the birds became long-day refractory. A moult from white to pigmented plumage occurred in females at the beginning and in males towards the end of the breeding season. This observation is consistent with the notion of an inhibitory effect of testosterone on moult in the males. Both sexes moulted simultaneously into white plumage in late September/early October.

Animals↗
PubMed1985

Reproduction in captive female Cape porcupines (Hystrix africaeaustralis).

Captive females attained sexual maturity at an age of 9-16 months and conceived for the first time when 10-25 months old. Adult females were polyoestrous but did not cycle while lactating or when isolated from males. The length of the cycle varied from 17 to 42 days (mean +/- s.d. 31.2 +/- 6.5 days; n = 43) and females experienced 3-7 sterile cycles before conceiving. Pregnancy lasted for 93-94 days (93.5 +/- 0.6 days; N = 4) and litter intervals varied from 296 to 500 days (385 +/- 60.4; n = 10). Litter size varied from 1 to 3 (1.5 +/- 0.66; n = 165) and the well-developed precocial young weighed 300-440 g (351 +/- 47.4 g; n = 19) at birth. Captive females reproduced throughout the year with most litters (78.7%; n = 165) being produced between August and March.

Animals↗
PubMed1992

Failure of a single postpartum prostaglandin treatment to improve the reproductive performance of dairy cows.

A study was conducted to evaluate the effects of postpartum prostaglandin treatment on reproduction in 3 seasonal calving dairy herds. Recently calved lactating dairy cows were paired on herd, age, calving date and previous production index. One cow in each of the 196 pairs received a single intramuscular injection of 25 mg of the prostaglandin analogue, dinoprost, between 14 and 28 days after calving. Subsequent reproduction was monitored. Within each herd and overall, there was no significant effect of treatment on the intervals from calving to first service, mating start date to first service, calving to conception, mating start date to conception and first service to conception. Treatment also had no significant effect on 21-day submission and pregnancy rates, on the proportion of each group not pregnant at the end of mating, and on first service pregnancy rates. Responses to treatment did not vary between cows calving within 50 days of mating start date and earlier calving cows or between cows aged less than 5 years and older cows.

Animals↗
PubMed2002

Basic properties and annual changes of follicle-stimulating hormone receptors in the testis of horseshoe bats, Rhinolophus ferrumequinum.

The unique reproductive patterns, delayed fertilization in females, and asynchrony between spermatogenesis and mating behavior in males are well documented in bats living in temperate latitudes. The present study was undertaken to examine follicle-stimulating hormone (FSH) receptors in the testis of bats, Rhinolophus ferrumequinum, during the annual reproductive cycle. Male bats were captured at natural roosting sites and testicular preparations were subjected to a radioligand binding assay for FSH receptors. The weight of paired testes increased considerably in the spermatogenic period and decreased from the mating to hibernation periods. Meiotic division in the testis was observed in the spermatogenic period but not the mating period. Serum testosterone concentrations increased in the spermatogenic period and rapidly decreased in the mating period. The binding of FSH was specific for mammalian FSHs and detected primarily in the testis. Scatchard plot analyses of the binding of FSH to bat testicular preparations showed straight lines, suggesting the presence of a single class of binding sites. The affinities (equilibrium association constant) of FSH receptors were consistent throughout the annual reproductive cycle. The specific binding per unit weight of testis and total binding in the paired testes were highest in the mating period and in the spermatogenic period, respectively, among reproductive periods. The accumulation of cyclic adenosine 3', 5'-monophosphate to FSH stimulation was higher in the spermatogenic period than in the hibernation period. These findings suggest that testicular function of bats is associated with seasonal changes in the number of binding sites, while the number per target cell and the activation of adenylate cyclase led by FSH-receptor complex considerably decreases in the hibernation period.

Adenylyl Cyclases↗
PubMed2002

Insulin-like growth factor-I as a possible hormonal mediator of nutritional regulation of reproduction in cattle.

The current review aims to establish insulin-like growth factor-1 (IGF-I) as the factor that signals nutritional status to the reproductive axis, and show that assessment of IGF-I in blood early postpartum during the negative energy balance (NEB) period could be used to predict both nutritional and reproductive status in dairy cattle. The review also explores the effect of nutritional status on circulating IGF-I concentrations and the endocrine role of IGF-I on the reproductive axis. IGF-I plays an important role in gonadotropin-induced folliculogenesis, ovarian steroidogenesis and corpus luteum (CL) function. It also modulates pituitary and hypothalamus function. IGF-I clearly has an endocrine role on the reproductive axis. Severe under nutrition significantly reduces plasma IGF-I concentrations. During the critical period of NEB in high yielding dairy cattle early postpartum, IGF-I concentrations are low in blood and its levels are positively correlated to energy status and reproductive function during this period. Changes in circulating IGF-I immediately postpartum may help predict both nutritional and reproductive status in dairy cattle. IGF-I is therefore one of the long sought factors that signal nutritional status to the reproductive axis.

Animal Nutritional Physiological Phenomena↗
PubMed1987

Pulsatility of reproductive hormones: physiological basis and clinical implications.

The secretion of LHRH from the median eminence, into hypophyseal portal blood provides a signal whereby the central nervous system interfaces with the endocrine system. The pulsatile nature of this system originates from phasic neural signals and, except in extreme cases where pulses are eliminated by the pituitary action of steroids, pulse frequency is determined by LHRH secretion. Steroidal feedback and other extrinsic influences that affect pulse frequency act via neural afferents to the LHRH neurons. Amplitude regulation may be by way of steroidal influence at the level of the pituitary gland, or indirectly via changes in LHRH pulse frequency. In this chapter, we have attempted to outline our current knowledge of factors regulating LHRH pulsatility and how this is transmitted into pulsatile gonadotrophin secretion. Regarding PRL secretion, we have outlined evidence that pulsatility is inherent in the lactotrophs, requiring no hypothalamic input. The possible roles of PRL releasing factors in circumstances like suckling and stress and of PRL inhibiting factors have been discussed with reference to the pulsatile nature of PRL secretion.

Animals↗
PubMed2005

Gynecologic health care for the adolescent solid organ transplant recipient.

The improved survival of pediatric recipients of solid organ transplants has prompted increased attention to quality of life issues. These include attainment of normal growth, involvement in romantic relationships, and the desire to control fertility. As an increasing number of adolescent transplant recipients are involved in normal social and sexual relationships, they require careful attention to their gynecologic and reproductive health care needs. Anticipating the onset of sexual activity before it occurs may help to prevent a mistimed pregnancy by providing or prescribing condoms and emergency contraception in advance. In addition, many transplant recipients can safely use the currently available methods of hormonal contraception provided there is careful attention to organ function, other medical problems, and concurrently prescribed medications. In adolescent patients, issues such as pubertal development and menstruation, contraception, and routine gynecologic health care are typically addressed by the patient's primary care provider. However, the complexity of the adolescent transplant recipient's medical care necessitates close collaboration among all health care providers caring for the patient. This review is intended to help the transplant team better understand the gynecologic health care needs and treatment options of their adolescent patients.

Adolescent↗
PubMed1989

Interrelationships between energy balance and postpartum reproductive function in dairy cattle.

Genetic improvement of dairy cows has markedly increased milk yield over the last three decades. Increased production has been associated with reduced conception rates (66% in 1951 versus 40 to 50% since 1975). Because conception rate in dairy heifers has remained higher, the metabolic demands of higher production may be related to the decline in reproductive performance in cows. During early lactation, increasing dietary intake fails to keep pace with rising milk production. The resultant negative energy balance and rate of mobilization of body reserves appear directly related to the postpartum interval to first ovulation and lower conception rate. Delays in the onset of normal ovarian activity, thus limiting the number of estrous cycles before breeding, may account for the observed decrease in fertility. Negative energy balance probably acts similarly to undernutrition and may manifest in delayed ovarian activity by impinging on pulsatile secretion of LH. Lower availability of glucose and insulin may also decrease LH pulsatility or limit ovarian responsiveness to gonadotropins. Alternatively, release of endogenous opioids in association with increasing feed intake or other lactational hormone responses may provide neural or pituitary inhibition of the pulsatile LH production that is requisite for ovarian follicular development.

Animal Nutritional Physiological Phenomena↗
PubMed1976

Hibernation and circannual rhythms of food consumption in marmots and ground squirrels.

In order to understand better the evolution and adaptive value of hibernation, ecological aspects and experimental studies of closely related hibernators, the Marmotini, are examined. The central hypothesis is that annual changes in the environment integrate three or, perhaps, four physiological processes: torpor, reporduction, consumption of food, and metabolism. Reproduction occurs promptly after emergence from hibernation. For most species, the breeding season is very short. Although the experimental data are rather meager, no variation in external factors has consistently altered the season of reproduction. Consumption of food and change in weight increases until July or September and then decreases. The large members of the Marmotini store their energy as fat, but small species store their energy as seeds and nuts. Experiments to test the hypothesis that some aspect of the supply, such as fat content, might vary seasonally have produced negative results. Complex experiments on the length of the photoperiod on woodchucks and several species of ground squirrels failed to alter the annual cycle of consumption of food. Animals kept in constant conditions showed a cycle of about 11 months, but woodchucks sent tto Australia changed their cycle in two years to match the seasons of the southern hemisphere. Experiments with temperature and torpor and castration did not alter the annual did not alter the rhythm...

Adipose Tissue↗
PubMed1998

Cellular proliferation in bovine luteal tissues of different reproductive states as demonstrated by Ki-67 immunocytochemistry.

Luteal tissue specimens of corpora lutea of oestrous cycle and pregnancy, post partum corpora lutea, and of luteinised follicular cysts of cows were harvested at slaughter. Cellular proliferation was examined employing Ki-67 immunocytochemistry. Ki-67 immunoreactivities could mainly be demonstrated within the nuclei of the theca interna and theca externa derived cell populations of cyclic corpora lutea. These cells obviously differentiated into vascular cells, connective tissue cells and small luteal cells. Proliferative activity was strongest in young corpora lutea and markedly reduced in the mature ones. During involution of corpora lutea of oestrous cycle Ki-67-positive cells were mainly found in vascular walls and connective tissue districts. Luteinised follicular cysts closely resembled cyclic corpora lutea. Corpora lutea of pregnancy exhibited foci of immunopositive cells close to blood vessels and connective tissue septae during whole gestation. Post partal luteal involution was characterised by Ki-67-positive cells within vascular walls and the surrounding stroma. Results suggest that luteal cellular proliferation is restricted mainly to theca interna-derived cells, which may differentiate to stromal cells and parenchymal cells.

Animals↗
PubMed2004

Reproductive aspects in female rats exposed prenatally to hydrocortisone.

We investigated the effects of hydrocortisone during the prenatal period and its later repercussion on reproductive aspects of female rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of pregnancy. Although the present study was not intended to identify mechanisms of toxicity, the treatment with hydrocortisone in the last period of pregnancy presented no signs of toxicity. The efficacy of the hydrocortisone in reducing the adrenal wet mass and plasma corticosterone levels immediately after delivery in both the treated mothers and in respective pups at birth may indicate impairment of the hypothalamus-pituitary-adrenal axis. In addition, the treatment with hydrocortisone did not interfere in the development of the female descendants until puberty. However, it affected the estrous cycle and fertility. Probably, the prenatal exposure to corticosteroids had altered at least partially the hypothalamus-pituitary-gonadal axis, resulting in the damages observed in adult life. These results indicate that the use of the hydrocortisone at a dose that apparently does not endanger the neonate led to undesirable effects in the adult reproductive phase, resulting in later deleterious alteration of the reproductive physiology in female rats.

Adrenal Glands↗
PubMed1993

Sex-biased lactational duration in a human population and its reproductive costs.

The authors tested the proposition that among humans (1) differences in lactational duration result in differences in costs of reproduction even under rich nutritional conditions; and (2) elimination of factors postulated to favor male-biased parental care will be reflected in elimination or reversal of sex-biased care. To do so, the authors examined the relationship between lactactational duration and fertility among Hutterites, a communal-living human population in which the levels of nutritional resources and fertility are high, breast feeding is the norm, contraceptive use is limited, and the collective social and economic system results in low resource variance among individuals. The authors demonstrate that even under good nutritional conditions, duration of nursing was a significant predictor of the length of time to next pregnancy and that nursing continued to suppress fertility after the resumption of menses. Moreover, the authors find that daughters were nursed longer than sons, leading to a longer interval to next pregnancy. The authors examine this uncommon, but not unique, finding of female-biased human parental care in the light of Hutterite social structure, and they explore the consistency of this finding with the most applicable models of parental investment.

Amenorrhea↗
PubMed1992

Reproductive patterns among Swedish women born 1936-1960.

An analysis was made of a cross-sectional survey of 4,299 women born in Sweden in the period 1936-1960, regarding their reproductive performance. Fecundability was only 12% lower for women in the 30-39 year age interval than for women up to 29 years of age. Cumulative pregnancy rates for individual years fell in the range 93-96%. No difference in fecundability could be discerned between women born in 1936-45 vis-à-vis 1946-60. Primary and secondary infertility were noted for 6.6% and 11.0% respectively of the entire population surveyed. Primary infertility, more prevalent among those born in 1946-60, was found to be related to a higher level of education, an urban life style and low age at first coitus. The risk of suffering a spontaneous abortion increased with advancing maternal age.

Adult↗
PubMed1990

Effects of limited suckling and varying prepartum nutrition on postpartum reproductive traits of milked buffaloes.

Effects of supplemental prepartum feeding and limited suckling on postpartum reproductive performance of milked Nili-Ravi water buffaloes were examined in two 2 x 2 factorial experiments. Prepartum feeding was either moderate (metabolizable energy = 32 Mcal/d) or high (46 Mcal/d) in Experiment 1 and high (46 Mcal/d) or very high (51 Mcal/d) in Experiment 2. Nutritional treatment was initiated about 75 d prior to calving and stopped at parturition. Half of the buffaloes were suckled by their calves twice daily (2 min at each milking) until second estrus. Prepartum feeding did not influence any trait measured in either experiment. Postpartum intervals to uterine involution, resumption of follicular development, first rise in milk progesterone, first palpable corpus luteum, and first estrus were longer for limited-suckled buffaloes than for those that were only milked. Most buffaloes (86%) showed at least one short luteal phase (8 to 13 d) before first estrus. Number of rises of progesterone before first estrus was greater for limited- suckled buffaloes in Experiment 2 but not in Experiment 1. Luteal activity after first estrus (15 to 19 d) and pregnancy rate to insemination at second estrus (average 50%) did not differ with limited suckling. In conclusion, postpartum anestrus of water buffaloes can be shortened by weaning calves at birth, regardless of supplemental feeding prepartum.

Animal Nutritional Physiological Phenomena↗
PubMed1995

Preweaning growth of Angus- (Bos taurus), Brahman- (Bos indicus), and Tuli- (Sanga) sired calves and reproductive performance of their Brahman dams.

Calves born to Angus (A), Brahman (B), or Tuli (T) bulls and B cows were evaluated to determine sire breed of calf effects on preweaning calf growth and reproductive performance of their dams. Records from 242 cow-calf pairs over 2 yr were used to assess birth weight, calf ADG, weaning weight, gestation length, and postpartum interval to estrus (PPI). The sire breed x sex of calf interaction was important (P < .05) for birth weight, weaning weight, and gestation length. Birth weights of BB males (32.8 +/- .8 kg) were significantly heavier than for AB and TB males (30.1 +/- .9 and 28.6 +/- .7 kg, respectively) and BB females (29.4 +/- .7 kg). As a main effect, sire breed of calf affected (P < .05) calf ADG, weaning weight, gestation length, and PPI. Calf ADG and weaning weights were greater for AB (.90 +/- .01 kg/d; 220.9 +/- 3.5 kg) than for TB (.81 +/- .01 kg/d; 200.4 +/- 3.0 kg) and BB calves (.78 +/- .01 kg/d; 198.8 +/- 3.5 kg). Gestation lengths differed (P < .01) among all calf genotypes (284, 288, and 294 +/- 1 d for AB, TB, and BB, respectively). Postpartum intervals were shorter (P < .05) for cows nursing BB calves (83 +/- 4 d) than for cows nursing AB (95 +/- 5 d) and TB calves (97 +/- 4 d). Tuli-sired F1 calves were inferior to Angus-sired F1 calves and similar to straightbred Brahman calves in preweaning growth. Crossbred calves had shorter gestations but longer postpartum intervals than purebred calves.

Aging↗