Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Multiparity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed2000

Decreased fertility among HIV-1-infected women attending antenatal clinics in three African cities.

Population HIV prevalence estimates rely heavily on sentinel surveillance in antenatal clinics (ANCs), but because HIV reduces fertility, these estimates are biased. To aid interpretation of such data, we estimated HIV-associated fertility reduction among pregnant women in ANCs in Yaoundé (Cameroon), Kisumu (Kenya), and Ndola (Zambia). Data collection followed existing HIV sentinel surveillance procedures as far as possible. HIV prevalence among the women was 5.5% in Yaoundé, 30.6% in Kisumu, and 27.3% in Ndola. The birth interval was prolonged in HIV-positive multiparous women compared with HIV-negative multiparous women in all three sites: adjusted hazard ratios of pregnancy were 0.84 (95% confidence interval [CI]: 0.62-1.1) in Yaoundé, 0.82 (95% CI: 0.70-0.96) in Kisumu, and 0.74 (95% CI: 0.61-0.90) in Ndola, implying estimated reductions in the risk of pregnancy in HIV-positive women of between 16% and 26%. For primiparous women, the interval between sexual debut and birth was longer in HIV-positive women than in HIV-negative women in all sites, although the association was lost in Ndola after adjusting for age and other factors. Consistent results in different study sites help in the development of standard methods for improving ANC-based surveillance estimates of HIV prevalence. These may be easier to devise for multiparous women than for primiparous women.

Adolescent↗
PubMed1995

Maternal expectations and experiences of labour pain--options of 1091 Finnish parturients.

A prospective survey of 1091 Finnish parturients was conducted in order to ascertain mothers' expectations for labour pain relief, to measure the actual pain during all three stages of labour and to question their satisfaction and the adequacy of pain relief on the third day following delivery. Antenatal expectations for pain relief were surveyed. Mothers were questioned on pain levels in the delivery room and 3 days after giving birth. Pain levels were ascertained using a visual pain score method. Antenatally, 90% of all parturients anticipated a need for pain relief during labour. In the delivery room over 80% of all parturients described their pain as very severe to intolerable, only 4% of the multiparous had low pain scores (0-2). After pain treatment 50% of multiparous women still had pain scores from 8 to 10, which reflects a lack of effective pain relief. Dissatisfaction with the childbirth experience was very low, and was associated with instrumental deliveries, but not with the usage of analgesia. 51% of all parturients complained of inadequate pain relief during childbirth, which, in multiparous women, was significantly associated with the second stage of labour.

Analgesia, Epidural↗
PubMed2005

Preliminary observations on the effect of parity on first day ultrasonic detection of embryo and its organs in bovine.

The aim of this study was to determine the effect of parity on the first day of ultrasonic detection of embryo and its organs using 8 MHz frequency. For this purpose, six nulliparous heifers, five primiparous cows and six multiparous cows of the Holstein breed were selected and mated by a single bull from the herd. From day 16 after mating, cows and heifers were examined by ultrasonography thrice weekly for the day of first detection of the embryo and its organs. The mean of first-day detection in heifers, primiparous and multiparous cows was as follows, respectively: allantois on days 22.3, 23 and 25.8; embryo proper on days 21.8, 23 and 27; heartbeat of embryo on days 26.1, 26.6 and 31.1; amnion on days 31, 31 and 30.8; limb buds on days 29.5, 28.8 and 30.6; stomach (abomasum) on days 32.2, 38.6 and 36.8; spinal column on days 32.6, 33.4 and 37.3; placentomes on days 33.3, 37 and 35.3; eyes on days 35.1, 35.4 and 38.6 and lens on days 40, 41.4 and 44. Although the mean of first day observation of all structures in heifers tends to be earlier than in the other groups, statistically, allantois, the embryo proper and its heartbeat in heifers and primipara were visualized significantly earlier than in multiparous cows. However, there were no differences between heifers and primiparous cows.

Animals↗
PubMed2004

Prostaglandin F2alpha treatment associated with timed artificial insemination in ewes.

Traditional treatments of two prostaglandin F2 alpha (PGF2alpha) doses at 10-day intervals or more did not result in acceptable pregnancy rates in timed artificial insemination (TAI) programmes in ewes. An explanation might be the undefined time-period of the onset of oestrus and ovulation after the treatment. Recently a consistent interval to oestrus and ovulation was obtained by giving PGF2alpha at day 3 post-ovulation, i.e. when the largest follicle of the first follicular wave of the cycle was still growing. This can be achieved when a second dose of PGF2alpha is given 7 days after a first dose. In this work, we evaluated the synchronization of oestrus and determined which of three different moments of TAI was the most successful using a PGF2alpha (PG-7d) protocol in a large flock. A total of 436 nulliparous and multiparous ewes were treated with two doses of a PGF2alpha analogue (delprostenate 160 microg, i.m.) separated by 7 days. Onset of oestrus was recorded twice a day and a single cervical TAI with fresh undiluted semen was performed either at 42 h (n = 152), 48 h (n = 120), or 54 h (n = 164), after the second PGF2alpha dose without taking into account the oestrous response. Pregnancy rate was determined by transrectal ultrasonography 30 days after insemination. Onset of oestrus was detected in 308 of 328 and 89 of 108 multiparous and nulliparous ewes, respectively (p < 0.001), within 72 h after treatment. The distribution of the onset of oestrus did not differ between multiparous and nulliparous ewes and the highest proportion of ewes in oestrus was detected between 25 to 48 h (313/397) from the second PGF2alpha dose. The pregnancy rate in ewes inseminated at 42 h tended to be higher than those inseminated at 48 h (p = 0.09) and was higher than those inseminated at 54 h (p < 0.05) (56/152, 31/120, 37/164; respectively). Therefore, the use of the PG-7d protocol resulted in a very high synchronization of oestrus with the highest concentration (around 80%) between 25 to 48 h from the end of treatment. The best pregnancy rate (37%) was obtained after a single cervical TAI with fresh semen at 42 h.

Animals↗
PubMed2006

Porcine field fertility with two different insemination doses and the effect of sperm morphology.

In swine artificial insemination, several dose regimens are applied, ranging from 1.5 x 10(9) to 6.0 x 10(9) spermatozoa per intra-cervical insemination dose. A lower sperm dose is more profitable for artificial insemination centres and offers a more effective use of superior boars. To evaluate fertility, 50 boars were used for a total of 10 773 homospermic first inseminations at a dose of 2 billion spermatozoa. In addition, 96 boars were used at a dose of 3 billion spermatozoa for 34 789 homospermic first inseminations. Fertility was determined by a 60-day non-return rate (NR%) of first inseminations. Litter size was registered by total number of piglets born separately in primiparous and multiparous farrowings. On average, a sow was inseminated 1.5 times. A significant decrease was observed in all three fertility parameters (NR%, litter size of both primiparous and multiparous farrowings) with a dose of 2 billion spermatozoa compared with a dose of 3 billion spermatozoa. The NR% was 75.8% and 84.0% (p < 0.001), the mean litter size of primiparous farrowings 10.1 and 10.7 (p < 0.001) and the mean litter size of multiparous farrowings 11.7 and 12.1 (p < 0.001) for 2 and 3 billion spermatozoa/dose, respectively. The proportion of normal spermatozoa in the sperm morphology analysis correlated significantly with NR% in both insemination regimens: p < 0.001, r = 0.604 and p < 0.05, r = 0.223 for 2 and 3 billion spermatozoa/dose, respectively. These results confirm that quantity can at least partly compensate for poor sperm quality. When the boars with <70% normal spermatozoa in the morphology evaluation were excluded from the data there were no correlation between the sperm morphology and NR%. However, the difference between the NR% and litter size remained statistically significant (p < 0.001) in favour for the bigger insemination dose. In conclusion, a decrease in sperm dose from 3 to 2 billion spermatozoa on commercial farms will severely decrease prolificacy at least under field conditions, where a sow is inseminated an average of 1.5 times/heat, and the semen is typically used within 3 days after collection. We recommend that under commercial circumstances the homospermic semen doses contain no <3 billion spermatozoa/dose.

Animals↗
PubMed2004

Video monitoring of smear-taking at colposcopy: relationship to cytology.

OBJECTIVE: To investigate the reasons why cervical smears occasionally fail to reflect the underlying pathology in the cervix even when the smear is taken at colposcopy. DESIGN: A randomised study of three different smear-taking devices. SETTING: A colposcopy clinic. POPULATION: Women attending the colposcopy clinic. METHODS: A smear was taken from 172 nulliparous and 100 multiparous women at colposcopy and the procedure was monitored on a video-imaging system. The cytological findings were compared with the biopsy report in 147 nulliparous and 85 multiparous women. MAIN OUTCOME MEASURES: Accuracy of cytology and the effect of a range of variables on the accuracy of cytology. RESULTS: Sampling of the transformation zone was incomplete in 15% of nulliparous women and 8% of multiparous women. Univariate analysis of a range of variables including parity, type of sampling devices, completeness of sampling of the transformation zone, size of the transformation zone, size of the lesion (aceto-white area) and location of the squamo-columnar junction showed that the accuracy of cytology was influenced by all these factors except for parity and smear-taking devices. Multivariate analysis showed that the location of the squamo-columnar junction, the size of the transformation zone area, the size of the aceto-white area and the ratio of the aceto-white area to the area of the transformation zone influenced the accuracy of cytology. CONCLUSIONS: Women with large transformation zone areas (>30.03 mm(2)) and/or small aceto-white lesions (<7.01 mm(2)) are more likely to have an inaccurate cytology reports than women with small transformation zone and women with larger aceto-white areas. A ratio of the aceto-white area to the area of the transformation zone of 0.22 or less increases the risk of disagreement between the cytological and histological findings.

Adult↗
PubMed2006

Recent impact of anal sphincter injury on overall Caesarean section incidence.

INTRODUCTION: Because of increasing recognition of obstetric anal sphincter injury and faecal incontinence, we examined the recent impact of these indications on our institutional Caesarean section incidence. METHODS: Retrospective review of the indications for multiparous Caesarean section was performed at the National Maternity Hospital for the 4 years 2000-2003, inclusive, to identify women in whom previous anal sphincter injury was an indication. Individual charts were reviewed and data regarding the nature and extent of previous anal sphincter injury were obtained. RESULTS: Among 17 586 consecutive multiparous deliveries, previous anal sphincter trauma constituted the indication for Caesarean delivery in 67 women, representing 0.4% of all multiparae, 2.9% of multiparous Caesarean sections and 1.3% of all Caesarean sections performed. Fifty (85%) of the 67 women who opted for prelabour Caesarean delivery following previous obstetric anal sphincter injury had symptoms of faecal incontinence (mean continence score 5, range 1-17). CONCLUSION: Notwithstanding recent increased awareness and documentation, anal sphincter problems represent a small influence on total Caesarean incidence.

Anal Canal↗
PubMed1977

Mixed lymphocyte culture reactions at delivery and in the puerperium: effects of parity, HLA antigens and maternal serum.

Mixed lymphocyte culture reactions between maternal and related neonatal cells at delivery, and maternal and paternal cells about a week after delivery, and the effect of maternal serum and HLA antigens on these reactions were studied in 11 families with primiparous or secundiparous mothers and in 13 families with multiparous mothers (six or more pregnancies). Weak or absent MLC response of the mother to her infant was observed in one-third of primiparous and secundiparous mothers and in one-half of multiparous mothers. In some cases the non-reactivity could be due to genetic similarity, i.e. HLA or HLA-D identity between the mother and her infant. In other cases, this was obviously not a valid explanation and no apparent reason for the non-reactivity was found. The MLC suppressing effect of maternal serum on MLC reactions at delivery and about a week later was not correlated with the strength of maternal-neonatal MLC reaction. Four of the ten sera from multiparous mothers studied a week after delivery had an inhibitory effect of 50% or more on MLC reactions involving stimulatory paternal cells. Responding paternal cells and other MLC combinations were also inhibited to varying degrees. None of the sera of primiparous and secundiparous mothers had an equally strong MLC inhibiting effect.

Adult↗
PubMed2002

The epidemiology of subfertility in non-seasonal calving dairy herds in the Camden region of New South Wales: description of population and incidence.

OBJECTIVE: To describe biographic, reproductive, production and disease characteristics of 965 Holstein cows from 10 non-seasonal calving dairy herds in the Camden region of New South Wales, and to describe the incidence of subfertility, that is, conception requiring > 2 inseminations, in this population. DESIGN: A retrospective epidemiologic study. METHODS: Computer records were used to determine biographic, reproductive, production and disease characteristics in all lactations that commenced between 1 July 1995 and 30 June 1996 and resulted in conception during that lactation. Differences in these characteristics among herds and between primiparous and multiparous cows were examined. The lactational incidence of subfertility for lactations commencing during the study period was determined. RESULTS: Ten herds with appropriate records and management structures entered the study. Herd size ranged from 86 to 203 lactating cows. Nutritional and reproductive management of these herds was typical of smaller pasture-based herds within the study region. Records from 1320 cows were available, of which 965 were considered suitable for descriptive analysis. Monthly variations in number of cows calving were noted, with number of lactations commenced by primiparous and multiparous cows peaking in January and October, respectively. Significant (P < 0.001) inter-herd differences for all reproductive, disease and milk production outcomes were detected for both the entire population and within primiparous and multiparous subgroups. Of 1041 cows submitted for insemination, 76 failed to conceive. The lactational incidence rate (LIR) of subfertility in all lactations was 21.1% (95% CI 19-24%). and among all cows conceiving was 22.8% (95% Cl 20-25%). The LIR of subfertility in primipara was 24.1% (95% Cl 19-28%) and varied widely between herds (10%-40%). The LIR of subfertility in multipara was 22.2% (95% Cl 20-25%) and also varied widely between herds (7%-46%). CONCLUSION: Parity and herd of origin should be considered in any further analyses of these data.

Animals↗
PubMed1994

Risk of breast cancer in relation to the interval since last full term pregnancy.

OBJECTIVE: To examine whether the risk of breast cancer is increased by a recent term pregnancy. DESIGN: Population based case-control study. SETTING: Eight areas in the United States. SUBJECTS: Cases were 2279 multiparous women residents of the eight areas aged 25-49 who were diagnosed as having breast cancer during 1980-2. Controls were 2357 multiparous women selected from the same areas by random digit dialing. MAIN OUTCOME MEASURE: Relative risk of developing breast cancer according to the time interval since last full term pregnancy. RESULTS: The distribution of intervals since the last term pregnancy was similar in cases and controls. Adjusted for age, parity, and age at first term pregnancy, the odds ratios observed for categories of years since the last full term pregnancy were: 0-2 years, odds ratio 1.16 (95% confidence interval 0.84 to 1.59); 3-6 years, odds ratio 1.21 (0.95 to 1.54); 7-9 years, odds ratio 1.04 (0.84 to 1.38); > or = 10 years, odds ratio 1.00 (reference). CONCLUSIONS: Among multiparous women aged 25-49 years there was no association between the risk of breast cancer and the time interval since the last full term pregnancy.

Adult↗
PubMed1997

Reproductive pattern, perinatal mortality, and sex preference in rural Tamil Nadu, south India: community based, cross sectional study.

OBJECTIVES: To study reproductive pattern and perinatal mortality in rural Tamil Nadu, South India. DESIGN: Community based, cross sectional questionnaire study of 30 randomly selected areas served by health subcentres. SETTING: Rural parts of Salem District, Tamil Nadu, South India. SUBJECTS: 1321 women and their offspring delivered in the 6 months before the interview. MAIN OUTCOME MEASURES: Number of pregnancies, pregnancy outcome, spacing of pregnancies, sex of offspring, perinatal and neonatal mortality rates. RESULTS: 41% of the women (535) were primiparous; 7 women (0.5%) were grand multiparous (> 6 births). The women had a mean age of 22 years and a mean of 2.3 pregnancies and 1.8 live children. The sex ratio at birth of the index children was 107 boys per 100 girls. The stillbirth rate was 13.5/1000 births, the neonatal mortality rate was 35.3/1000, and the perinatal mortality rate was 42.0/1000. Girls had an excess neonatal mortality (rate ratio 3.42%; 95% confidence interval 1.68 to 6.98; this was most pronounced among girls born to multiparous women with no living sons (rate ratio 15.48 (2.04 to 177.73) v 1.87 (0.63 to 5.58) in multiparous women with at least one son alive). CONCLUSIONS: In this rural part of Tamil Nadu, women had a controlled reproductive pattern. The excess neonatal mortality among girls constitutes about one third of the perinatal mortality rate. It seems to be linked to a preference for sons and should therefore be addressed through a holistic societal approach rather than through specific healthcare measures.

Abortion, Spontaneous↗
PubMed1995

Peripartum cardiomyopathy: experiences at King Edward VIII Hospital, Durban, South Africa and a review of the literature.

The clinical profile of patients with peripartum cardiomyopathy (PP-CMO) seen in the patient population in Durban, South Africa, is documented. Parameters such as age, multiparity, time of presentation and the role of hypertension in PP-CMO were evaluated. The study comprised 97 patients seen over a 4 year period. Group 1 (n = 63), had a good outcome at follow-up and group II (n = 34), had an adverse outcome, namely: persistently severe symptoms New York Hospital Association, Class III/IV; major thromboembolic complications; or a fatal outcome. These results confirm that PP-CMO is more likely to occur in the older and multiparous female. Increasing age and multiparity did not adversely affect outcome. Eighteen per cent of the study group were primiparous, and a third of these had an adverse outcome. Late presentation of symptoms (after 1 month postpartum) tended to favour an adverse outcome (P = 0.06). Fifteen of the 19 patients with complete obstetric records had antenatal hypertension: in nine blood pressure levels were > or = 160/110 mmHg. We were unable to ascertain the prognostic value of hypertension in PP-CMO. In conclusion, this study showed a high incidence of PP-CMO in the local African population (1:1000 deliveries), and a high complication rate (35%): it suggests that early diagnosis and appropriate therapy may avert an adverse outcome.

Adult↗
PubMedDate not supplied

Reevaluation of Friedman's Labor Curve: a pilot study.

OBJECTIVE: To reevaluate the average length of each phase/stage of labor for multiparous and primiparous women in North America who received no regional anesthesia or oxytocin augmentation or induction, to describe a range of labor lengths associated with good childbirth outcomes, and to determine if there is a consensus among labor and delivery nurse managers responding to the survey regarding the need to revise Friedman's Labor Curve. DESIGN: This pilot study used a descriptive and anonymous cross-sectional survey design. Surveys were mailed to 500 maternity care agencies in the United States, Canada, and Mexico with a return rate of 17.8% (n = 89). Each participating agency was asked to submit five patient cases to be included in the analysis. SAMPLE AND SETTING: The sample of patient cases (n = 419) was drawn from randomly selected maternity care agencies throughout North America representing all sizes of agencies and geographic locations. The cases submitted for analysis represented women 14 to 44 years of age with varying ethnicities who received no regional anesthesia or oxytocin augmentation or induction. Twenty-three percent of the women in the sample (n = 97) were primigravidas. RESULTS: The average length of labor for primiparous and multiparous women today is similar to the average length of labor described by Friedman in 1954. However, a wider range of "normal" was found in cases included in the current study. Primiparous women remained in the first stage of labor for up to 26 hours and the second stage of labor up to 8 hours with no adverse effects to mother or infant. Multiparous women remained in the first stage of labor for up to 23 hours and the second stage of labor for up to 4.5 hours with good birth outcomes. In addition, 87.6% of nurse managers responding to the survey believed that Friedman's Labor Curve should be revised to meet the needs of current patient populations, technological advances, and nursing responsibilities. CONCLUSIONS: This study suggests that the parameters to determine if a labor is progressing satisfactorily may need to be expanded. With the availability of technology to assess maternal and fetal well-being, labor should be allowed to progress past the rigid 2-hour time limit for the second stage of labor artificially imposed on women in some childbirth settings. More emphasis should be placed on the nursing assessment techniques used to reassure the family and health care practitioners that labor is progressing safely and the nursing interventions that may have an impact on the length of each stage of labor.

Adolescent↗
PubMed2006

Reproductive experience reduces circulating 17beta-estradiol and prolactin levels during proestrus and alters estrogen sensitivity in female rats.

The reproductive experiences of pregnancy, parturition, and lactation affect a range of neural and endocrine processes after the end of lactation. In women, previous parity results in reduced circulating prolactin (PRL) and androgen levels years after giving birth. Reductions in PRL secretion also occur in reproductively experienced, female rats. In the present study we examined the status and regulation of estradiol (E(2)) and PRL during the reproductive cycle after reproductive experience. These hormones regulate one another and have been implicated in a number of disease and aging processes. Using a rat model, the patterns of E(2) and PRL secretion, pituitary PRL content, and estrogen receptor alpha expression were characterized from 1200-1800 h on proestrus in age-matched, primiparous and nulliparous animals. The possible effect of parity on estrogen sensitivity was then examined by challenging nonlactating, ovariectomized, age-matched, multiparous and nulliparous rats with estradiol benzoate (EB; 0, 1, 5, 25, and 125 microg/kg) and measuring PRL responses 24 and 48 h later. Previous parity resulted in modest, yet significant, reductions in E(2) and PRL levels on proestrus, a limited increase in pituitary estrogen receptor alpha expression, and a significant shift in estrogen sensitivity, as measured by EB-induced PRL secretion. Nulliparous animals were more sensitive than multiparous rats to the two lower doses of EB, whereas multiparous animals were more responsive to the highest EB dose. These unique parity-induced alterations in the female's endocrine state that persist beyond lactation may impact a multitude of estrogen-mediated processes over the female's adult life span.

Animals↗
PubMed2005

Effect of maternal age and parity on preimplantation embryo development and transport in the golden hamster (Mesocricetus auratus).

Preimplantation embryo development was studied in the golden hamster (Mesocricetus auratus). Three groups of regularly cycling female hamsters were used: (I) 30 nulliparous young female (NYF) hamsters; (II) 24 nulliparous adult female (NAF) hamsters and (III) 30 multiparous adult female (MAF) hamsters. Female hamsters were mated with male hamsters of proven fertility. Only 15 min were allowed for mating. The moment of ejaculation was registered. Female hamsters were killed from 60 to 69 h after coitus. Corpora lutea were counted in both ovarian surfaces. Oviducts and uterine horns were flushed separately and embryo number, stage of development and distribution were recorded. Adult female hamsters, nulliparous and multiparous, had significant higher ovulation rates than NYF, but their reproductive efficiency was significantly lower. Preimplantation embryo development and transport were highly synchronous in NYF, but not in adults. Morulae were observed in NYF as early as 62-63 h after coitus. In adult female hamsters, significant numbers of morulae were found until 66-67 h. On the contrary, in NYF four-cell embryos were detected only until 60-61 h, while four-cell embryos were found until 64-65 h in NAF, and until 66-67 h in MAF. Embryo transport from the oviduct to the uterus is practically completed at 62-63 h after coitus in NYF, while it is evidently retarded in adult animals. In NYF all eight-cell embryos reached the uterus by 62 h after coitus. In adult female hamsters, both nulliparous and multiparous, a considerable number of eight-cell embryos fail to migrate into the uterus even at 67 h after coitus.

Animals↗
PubMed1993

Uterine activity in spontaneous labour and maternal peripheral plasma prostaglandin E2 and F2 alpha metabolites.

The relationship between maternal peripheral plasma concentrations of prostaglandin E2 and prostaglandin F2 alpha metabolites (bicyclo-PGEM and PGFM respectively) and the level of uterine activity in spontaneous labour was studied in 10 nulliparous and 10 multiparous women. Plasma prostaglandin metabolites were measured by radioimmunoassay. Uterine activity was quantified by computer analysis of changes in intrauterine pressure and expressed as mean active pressure (MAP). As labour progressed, both parity groups showed a significant rise in MAP which was associated with a significant increase in the levels of PGFM. However, the percentage rise in PGFM did not significantly correlate with the percentage rise in MAP. At all stages in labour PGFM and MAP levels were higher in the nulliparous group compared with the multiparous group. Bicyclo-PGEM levels showed no significant change in the nulliparous group but rose in late first stage/second stage in the multiparous group. Our observations support a role for prostaglandin F2 alpha in the generation of uterine activity in spontaneous labour. However, further study is required to elucidate the mechanisms controlling prostaglandin production by the fetal membranes and decidua in vivo, and how this relates to maternal peripheral plasma prostaglandin metabolite concentrations and the level of uterine activity.

Dinoprost↗
PubMed1982

Effect of climatic conditions on peripheral concentrations of LH, progesterone and oestradiol-17 beta in high milk-yielding cows.

In a subtropical climate, high milk-yielding dairy cows were kept during the summer under ventilated conditions or untreated; during the winter, cows were kept untreated. The afternoon mean rectal temperature for multiparous cows in the three groups was 39.3, 39.8 and 38.9 degrees C, respectively. Each group was significantly different from the other two (P less than 0.05). Plasma LH concentrations measured every 6 h during the oestrous period in 38 'summer' cows were not significantly different for untreated and ventilated animals. Conception rate was higher (P less than 0.05) in cows that showed oestrous behaviour before the LH surge reached its peak than in cows in which oestrus coincided with or occurred later than the LH surge. Plasma progesterone levels measured in 62 cows during the oestrous cycle before the first insemination were higher in the winter than in the summer in multiparous, but not in primiparous, cows. Ventilation increased progesterone levels in multiparous and primiparous cows. Plasma oestradiol-17 beta levels did not differ between groups until 36 h before the onset of oestrus, when they remained at 4.75 pg/ml in winter and summer-ventilated cows but increased to 6.75 pg/ml in summer untreated cows (P less than 0.01). Significant negative correlations were found between oestradiol levels observed 12 h before to 12 h after the onset of oestrus and plasma progesterone concentration during both the preceding and the subsequent oestrous cycles.

Animals↗
PubMed1998

Reproductive experience and opioid regulation of luteinizing hormone release in female rats.

The objective of the present study was to determine whether reproductive experience that produces shifts in opioid regulation of prolactin secretion and behavioural functions also alters opioid regulation of LH during the oestrous cycle or lactation. In Expt 1 the effect of naloxone administration (i.v.) on LH was compared between age-matched, nulliparous and primiparous, catheterized female rats on dioestrus II. In Expt 2, the effects of multiple reproductive experiences on opiate control of LH were investigated using cyclic, nulliparous and multiparous (three litters) rats. In both experiments, no differences in naloxone-stimulated LH release were found between groups even though multiple reproductive experiences resulted in the prolongation of oestrous cyclicity. In Expt 3, day 8 lactating primiparous rats were administered 2, 5, 10 or 25 mg naloxone kg-1 i.v. The three lowest naloxone doses, but not the 25 mg kg-1 dose, significantly increased LH concentrations. The possible effects of prior reproductive experience on opioid control of LH during lactation were then investigated. Naloxone at 0.5 mg kg-1, but not at 2 mg kg-1 or 10 mg kg-1, stimulated a significantly greater rise in LH in multiparous (two litters) than in primiparous females. Overall, these data indicate that while modest differences were found in naloxone-induced LH responses between multiparous and primiparous animals during lactation, reproductive experience did not significantly alter opioid regulation of LH during subsequent oestrous cycles at the naloxone doses examined. Hence, the effects of reproductive experience on opioid regulation of LH are less pronounced than those previously found for opioid regulation of prolactin and behaviour.

Analysis of Variance↗