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PubMed1986

Uterine and embryonic metabolism after diapause in the tammar wallaby, Macropus eugenii.

Pouch young were removed from lactating tammars to terminate embryonic diapause. Uterine metabolism was assessed at periods afterwards by incubating endometrial explants with [3H]leucine, and measuring the incorporation into acid-soluble material. Blastocysts were incubated with [3H]uridine to assess uptake and incorporation into acid-soluble material. Uterine reactivation, shown by an increase in the rate of leucine incorporation into secreted protein, was evident by Day 4 after removal of pouch young and was significantly more in both secreted and tissue protein by Day 6. Both continued to increase in gravid and non-gravid uteri up to Day 12. By the end of pregnancy (Day 26) uterine metabolism in the gravid uterus produced 2-3 times more secreted protein than in the non-gravid uterus, demonstrating a local feto-placental influence on the uterus. Tissue incorporation had declined in endometrium of gravid and non-gravid uteri by Day 26. Day 5 embryos were metabolically more active than in quiescence, although expansion of the embryos was not seen until Day 9. The early reactivation of the uterus and embryo from diapause suggests that it is not triggered by the previously described peaks of progesterone and oestradiol in plasma at Day 5, although there may be an earlier, increased sensitivity to these steroids which allows uterine reactivation to precede changes in peripheral plasma concentration.

Animals↗
PubMed2000

Progesterone and oestrogen receptors in the female genital tract throughout pregnancy in tammar wallabies.

The tammar, Macropus eugenii, is a monovular macropodid marsupial which has a post-partum oestrus and an 11 month embryonic diapause. Progesterone and oestradiol cytosol receptors were measured by Scatchard analyses and single point analysis in the lateral vagina, endometrium and myometrium of the gravid and contralateral non-gravid uterus throughout pregnancy, immediately after parturition and during seasonal reproductive quiescence. In endometrial tissues, both progesterone and oestradiol receptors doubled in concentration in both gravid and non-gravid uteri between day 0 and day 5 of pregnancy, coinciding with previously described peak values in peripheral plasma progesterone and oestrogen. Receptor concentrations in endometrial tissue during seasonal quiescence were not significantly different from those immediately after reactivation. After day 12 of pregnancy, downregulation of both progesterone and oestradiol cytosolic receptors occurred concomitant with the increase in progesterone in the peripheral plasma. However, there was a unilateral increase in oestradiol receptor concentrations in endometrium obtained from the non-gravid uterus between day 25 of the 26.5 day gestation and immediately after parturition. Myometrial receptor concentrations mirrored those of the endometrium but were lower. Concentrations of progesterone receptor in the lateral vaginae were at the lower limit of detection, while the oestradiol cytosol receptor concentrations were even lower in this tissue. Thus, the steroid receptor concentrations provide another example of local unilateral endocrine responses in the reproductive tract of the tammar. These results also indicate that the downregulation of progesterone and oestradiol receptors that occurs in both uteri in mid- and late-pregnancy is selectively and locally reversed before parturition in the non-gravid endometrium in response to the local effects of follicular oestradiol from the ipsilateral ovary.

Analysis of Variance↗
PubMed2006

Comparison of mosquito trapping method efficacy for West Nile virus surveillance in New Mexico.

As part of the West Nile virus surveillance program for the state of New Mexico, 13 sites along the Rio Grande River were sampled for mosquitoes during spring and summer 2003. We evaluated 3 different trapping procedures for their effectiveness at capturing selected species of mosquitoes. The 3 methods used were a dry ice-baited Centers for Disease Control and Prevention (CDC) light trap set 1.5 m above the ground (standard method), a CDC light trap suspended within the forest canopy, and a gravid trap set on the ground. Thirteen sites were sampled for 10 1-night periods biweekly from May through September. The relative numbers of captured Culex tarsalis, Cx. salinarius, Cx. quinquefasciatus, and Aedes vexans as well as the numbers of total recorded captures of all species were compared for each trapping method. Significant differences were observed for each species by location and by trapping method. Culex tarsalis was most commonly caught in canopy or standard CDC traps, especially in cottonwood bosque. Culex salinarius was found most frequently in association with marshy water, and was most often caught in gravid or standard light traps. Culex quinquefasciatus was captured almost exclusively in gravid traps within urban areas. Aedes vexans was primarily sampled in standard CDC light traps and found most frequently in wooded areas near floodplains. With the exception of Cx. Quinquefasciatus, no species was collected significantly more frequently in gravid or canopy traps than in the standard CDC light trap. Our findings do not support altering the methods currently used in New Mexico, namely, the use of 1.5-m CDC light traps and gravid traps. An increased use of gravid traps seems to be warranted in monitoring urban vector populations (specifically Cx. quinquefasciatus and Cx. salinarius) that may be involved in human transmission.

Aedes↗
PubMed1998

[Serum leptin in women during the third trimester of pregnancy].

Leptin is a small protein produced mainly by adipocytes. Recently, its relationship to obesity has been studied extensively. It was proved that obese individuals have either relative or absolute leptin deficiency. Several years ago, leptin was found to be produced also by the placenta. This stimulated us to study relationship between leptinemia and placental hormones in 85 women in the second gravidity trimester. Within the prenatal screening, these pregnant women were subjected to analysis of AFP, hCG, SP-1 glycoprotein and leptin and the results obtained were processed statistically. The control group consisted of 20 nonpregnant women with tetany. Women in the second gravidity trimester were found to have a significantly higher leptinemia than nongravid women (even with respect to body weight). This may be due to a larger amount of adipose tissue during gravidity and also leptin-resistance. Moreover, we recorded a negative correlation between leptinemia related to body weight and concentration of SP-1 glycoprotein. This finding supports the presumption that mother's leptinemia correlated negatively in the second gravidity trimester with quality and quantity of the placental syncytiotrophoblast. Our findings can be explained as follows: the biological effect of leptin is metabolically unfavourable for the growth of the foetus and the placenta. An increased leptinemia with advancing gravidity can be caused by a larger fatty mass and an increased activity of adipocytes when leptin presence increases in system circulation but the organism begins to be leptin-resistant and an "unfavourable" metabolic effect fort the gravid woman and the foetus is not distinct. These findings thus support the hypothesis postulating the nonsignificance of leptin production in human placenta and on the contrary the necessity of leptin-resistance for foetus development from the metabolic point of view. Thus, a decreased leptinemia immediately before and after the delivery could be caused by the still unclear regulators of leptin sensitivity. This is again a metabolically highly favourable state (reduced appetite, decreased body weight, increased energy output and others).

Adipose Tissue↗
PubMed1979

[Vitamin E concentration in the blood serum of sows during pregnancy and lactation].

The dynamics of vitamin E in the blood serum of sows of the Slovak Large White breed was studied from the 10th day of gravidity to the 20th day of lactation. A slight variation was observed in the average values of serum vitamin E from the 10th to the 50th day of gravidity (from 0.134 to 0.122 and 0.129 mg per 100 ml). A rise to the absolutely highest average values of serum concentration of vitamin E, 0.166 mg per 100 ml, was ascertained in the period from the 70th to the 90th day of gravidity. In the subsequent period, i.e. 110th day of gravidity, the value dropped to 0.120 mg per 100 ml, and on the 5th day of lactation the absolutely lowest value (0.095 mg per 100 ml) for the whole study was obtained. On the 20th day of lactation the serum concentration of vitamin E increased on an average to 0.103 mg per 100 ml. These data indicate the critical periods in the levels of vitamin E; these are from the 90th to the 100th day of gravidity and the first days of lactation when the concentration of vitamin E markedly decreases. If vitamin E is not supplemented to the sows during gravidity in sufficient amounts, preclinical and clinical vitamin E deficiency can be expected to occur.

Animals↗
PubMed2005

[Correlative factors analysis of recurrence of endometriosis after conservative surgery].

OBJECTIVE: To determine the correlative factors with recurrence of endometriosis after conservative surgery. METHODS: A cohort study was performed on 285 patients who had a minimum of 36 months of follow-up after conservative surgery for endometriosis. All patients underwent clinical interview, physical examination and ultrasonography. The factors measured included: age at surgery, age at onset of disease, gravidity, parity, tenderness nodule at cul-de-sac (yes/no), uterus mobility (movable/fixed), serum CA(125) level, type of operation (laparoscopy/laparotomy), history of operation for endometriosis (yes/no), side of endometrioma (left/right/bilateral), intraoperative revised classification American Fertility Society (r-AFS) scores, post-operative r-AFS scores, highest post-operative temperature, post-operative adjuvant therapy, post-operative gravidity and parity. The recurrent rate and its predictive factors were evaluated and the univariate, multivariate COX regression and Kaplan-Meier analyses were performed to determine the predictive factors for recurrence of endometriosis. RESULTS: The related factors and their odds ratio (OR) by univariate analysis were as follows: history of endometriosis surgery, 13.630 (P < 0.01); nodules with tenderness at cul-de-sac, 6.133 (P < 0.01); post-operative administration of clomiphene, 5.173 (P < 0.01); left endometrioma, 4.503 (P < 0.01); bilateral endometrioma, 3.709 (P < 0.01); post-operative r-AFS scores, 1.831 (P < 0.01); post-operative gravidity, 0.392 (P < 0.05); post-operative administration of progesterone for 6 months, 0.472 (P < 0.01); laparoscopic surgery, 0.567 (P < 0.05); pre-operative parity, 0.640 (P < 0.05); pre-operative gravidity, 0.759 (P < 0.05); age at onset of disease, 0.912 (P < 0.01) and age at surgery, 0.932 (P < 0.05). Meanwhile, the related factors and their odds ratio (OR) by multivariate COX analysis were as follows: history of endometriosis surgery, 8.219 (P < 0.01); bilateral endometrioma, 6.369 (P < 0.01); left endometrioma, 2.682 (P < 0.05); tenderness nodules at cul-de-sac, 2.154 (P < 0.05); post-operative administration of clomiphene, 1.860 (P < 0.05); post-operative r-AFS scores, 1.188 (P < 0.01); post-operative gravidity, 0.253 (P < 0.01); post-operative administration of progesterone for 6 months, 0.518 (P < 0.05); age at surgery, 0.937 (P < 0.01). CONCLUSIONS: The risk factors for recurrence of endometriosis include a history of endometriosis surgery, bilateral endometrioma, left endometrioma, tenderness nodules at cul-de-sac, post-operative administration of clomiphene, post-operative r-AFS scores,whereas the protective factors include the post-operative gravidity, post-operative adjuvant therapy and age at surgery.

Adult↗
PubMed1990

[Histologic and biochemical studies on the uteri of ovariectomized gilts during the first two months of pregnancy after different hormone substitutions. 1. Changes in the structure of the placenta during pregnancy weeks 3-8 after constant high doses of progesterone and estradiol benzoate].

Sixteen pregnant gilts were ovariectomised (Groups 1 and 2: 11th to 15th days of gravidity, Group 3: 19th to 22nd days of gravidity, Group 4: 34th to 45th days of gravidity). Daily intramuscular injections of 120 mg of progesterone and 250 micrograms of oestradiol benzoate were applied to them, beginning on the day of ovariectomy to preserve gravidity. All experimental animals were sacrificed between the 21st and 25th days of gravidity (Group 1) and between the 31st and 37th days (Groups 2 and 3) as well as between the 52nd and 61st days (Group 4). Living and dead embryos were numerically recorded, and histological als well as biochemical studies were conducted in all uteri. Embryo survival rates were normal, that is between 62.8 and 80 percent in Groups 1, 2, and 3, with the numbers of living embryos being 9.5, 7.5, and 8.0. Gravidity-specific uterus alterations were typical, despite constant hormone substitution. The thickness of endometrium declined with significance over the period under review. Plication was intensified, while the surface epithelium was flattened. Vascularisation increased, particularly in the subepithelial region, and the endometrial stroma became more oedematous. Full functionality was retained by the uterine glands in the period under review (increase in glandular epithelium as well as rising activity of alkaline phosphatase). Significant increase was recorded from the activity of acid phosphatase, whereas glycogen concentrations went down in the myometrium.

Animals↗
PubMedDate not supplied

[Seasonal variations in Aedes Aegypti populations in Monterrey, Mexico].

Seasonal variation of the populations of the dengue vector mosquito Aedes aegypti, in the city of Monterrey, N.L., Mexico, showed a bimodal pattern. The first peak is lower and appeared at early June, while the second and higher one was observed in the second week of October. 1,419 female mosquitoes were caught in this study. Females with fresh red blood in the stomach were present in all the catches, gravid females (mature eggs in the ovaries) being more abundant than the non-gravid ones. The gravid females with red blood are the oldest of the vector population. Nevertheless, in October, 40 per cent of females had red blood and of these, 37 per cent were gravid. In relation to the biting rate, a 10 females/hour-man rate was recorded for the first peak and a 13.3 females/hour-man rate for the second one. There were 32 per cent of females involved in multiple feedings during the weekly catches. This incidence increases to 40 per cent in October. These rates were calculated on the basis of females with fresh blood in the stomach; from these the gravids and non-gravids have at least three and two multiple feedings, respectively. Finally the epidemiological importance of these multiple feedings on dengue transmission is discussed.

Aedes↗
PubMed2005

Gestational diabetes is associated with depressed adiponectin levels.

OBJECTIVE: Adiponectin is a 29-kd adipocyte-secreted protein that has been linked to insulin resistance in obesity and diabetes. The aim of the present study was to evaluate adiponectin levels in the insulin-resistant state of diabetes in gestation. METHODS: Term, gravid subjects with diabetes (n = 31; age, 30.0 +/- 0.9 years; weight, 98.8 +/- 4.6 kg) and healthy, term, gravid subjects (n = 27; age, 26.1 +/- 1.1 years; weight, 91.2 +/- 3.78 kg) were examined. The diabetes group consisted of 11 class A1, 11 class A2, and nine class B subjects. Plasma insulin, glucose, adiponectin, and leptin were measured on samples obtained immediately before Cesarean or vaginal delivery. Data were presented as means +/- SE, and significance is set at P < or = .05. RESULTS: We observed decreased adiponectin levels in class A2 (4.93 +/- 0.58 microg/mL; P = .013) and class B diabetics (3.33 +/- 0.56 microg/mL; P = .001) as compared to controls (8.17 +/- 0.82 microg/mL), while a nonsignificant decrease was also observed in class A1 (6.58 +/- 1.13 microg/mL; P = .213). When grouping all gravid subjects, we observed that non-Caucasian subjects (n = 42) (5.51 +/- 0.51 microg/mL; P = .003) had lower adiponectin levels than Caucasian subjects (n = 16) (8.88 +/- 1.11 microg/mL). Within the non-Caucasian group, we found significantly lower adiponectin levels in diabetic gravid subjects (class A2: 4.24 +/- 0.75 microg/mL; P = .044; and class B: 3.33 +/- 0.56 microg/mL; P = .005) compared with nondiabetic gravid subjects (7.05 +/- 0.80 microg/mL). CONCLUSION: Class A2 and B gestational diabetes are associated with suppressed levels of adiponectin, similar to that found in other insulin-resistant states (type II diabetes and obesity).

Adiponectin↗
PubMed2004

Effect of benzyl isothiocyanate on spontaneous and induced force of rat uterine contraction.

The present study examines the effect of benzyl isothiocyanate (BITC) on uterine contraction in vitro. BITC (10-320 microM) caused irreversible, concentration-dependent inhibition of the spontaneous, prostaglandin F(2alpha) (PGF(2alpha)) and oxytocin-induced force of gravid and non-gravid rat uterine contractions in contrast to equivalent concentrations of DMSO (solvent control). At 160 microM of BITC, spontaneous, PGF(2alpha) and oxytocin-induced force of gravid rat myometrial contractions were reduced to 16 +/- 6%, 15 +/- 7 % and 17 +/- 4% (of the control contractions), respectively. Moreover, at 320 microM of BITC, spontaneous, PGF(2alpha) and oxytocin-induced force of non-gravid rat uterine contractions were reduced to 10+/-5 %, 4+/-1 % and 7+/-2 % (of the control contractions), respectively. Incubation of isolated non-gravid rat uterine strips in Ringer Locke solution containing 100 microM of BITC for 1h prior to recording their activity also caused significant and irreversible depression of KCl (60mM)-induced tension development in the uterus relative to the solvent control (P < 0.01). In 56% of BITC-pretreated uterine tissues, spontaneous contractions were totally abolished. Cryosections of BITC-treated uterus (hematoxyline and eosin stained) examined under light microscope revealed structural disintegrity with marked vacuolar degeneration of the endometrium and myometrium. It thus appears that like the vascular smooth muscle (reported by previous workers), BITC is also capable of causing functional aberration of isolated uterus by provoking degeneration of the myometrium.

Animals↗
PubMed2003

The effect of intrauterine administration of estradiol on postpartum uterine involution in cattle.

In cattle, the first postpartum dominant follicle has a predilection for the ovary contralateral to the previously gravid uterine horn. However, the presence of an estradiol-secreting dominant follicle in the ipsilateral ovary is a marker of subsequent fertility, possibly due to a localized effect of ovarian estradiol on uterine involution. The present study tested the hypothesis that estradiol increases the rate of uterine involution when administered into the previously gravid uterine horn around the expected time of selection of the first postpartum dominant follicle. Dairy cows were treated with 10 mg estradiol benzoate (n=15) or saline (n=14) administered through the cervix into the previously gravid uterine horn lumen on Days 7 and 10 postpartum. Uterine involution was monitored by daily transrectal ultrasonography and estimation of peripheral plasma concentrations of PGFM and acute phase proteins, while ovarian function was monitored by ultrasonography and measurement of plasma hormone concentrations. There was no effect of estradiol treatment on the diameter of the previously gravid or nongravid uterine horns, nor on the plasma concentrations of PGFM or acute phase proteins. However, cows in which the first postpartum dominant follicle ovulated during the study period had a smaller diameter of the previously gravid (P<0.01) or nongravid uterine horns (P<0.001) compared with cows in which the follicle regressed. Thus, our hypothesis was not proven, and the opposite pathway of utero-ovarian signaling may be more important during the postpartum period.

Administration, Intravaginal↗
PubMed1998

Mesotocin receptors during pregnancy, parturition and lactation in the tammar wallaby.

Mestocin receptor concentrations in membrane preparations from reproductive tissues of the tammar Macropus eugenii throughout gestation and lactation were assessed using [3H]-oxytocin as the ligand. There was a single binding site which bound both mesotocin and oxytocin with high and similar affinities. Mesotocin receptor concentrations in the myometrium were low (708 +/- 199 fmol mg-1 protein) in early and middle gestation but increased significantly on day 23 of pregnancy of the 26-day gestation period to 1921 +/- 552 fmol mg-1 protein. Myometrial receptors reached a peak of 2483 +/- 575 fmol mg-1 protein on days 25 and 26 of gestation, but returned to basal levels about an hour after birth. Receptor concentrations in the contralateral non-gravid uterus were much lower (605 +/- 75 fmol mg-1) and did not significantly increase throughout the period of gestation but dropped one day before birth. Mesotocin receptors were undetectable in the endometrium, the yolk sac placenta and the lateral, median and anterior vagina of all animals tested. In the lactating mammary gland after birth mesotocin receptors were initially high (588 +/- 38 fmol mg-1) but decreased after 200 days and by late lactation were 224 +/- 55 fmol mg-1 protein on day 240, close to the time of weaning. Mesotocin receptors in the ipsilateral non-lactating gland were also high in early lactation (430 +/- 153 fmol mg-1) and declined in late lactation (62 +/- 20 fmol mg-1). The changing concentrations of mesotocin receptors in pregnancy and lactation demonstrate that they are specifically regulated in tammar reproductive tissues. The increase in mesotocin receptors in gravid, but not in the non-gravid myometrium three days before birth may make the uterus responsive to the surge of mesotocin at birth. Since this rise is unilateral and only occurs in the gravid myometrium it must be due to local effects from the ipsilateral ovary or the feto-placental unit. Likewise, the down-regulation of mesotocin receptors in the contralateral, non-gravid myometrium may be due to its proximity to the developing follicle. The changing concentrations in the lactating and the adjacent, non-lactating mammary gland also reflect a differential regulation of mesotocin receptors, probably mediated via the sucking stimulus. Thus, local influences appear to be of primary importance in the regulation of mesotocin receptors during reproduction in this marsupial.

Animals↗
PubMed2000

Risk of meconium-stained amniotic fluid in different ethnic groups.

BACKGROUND: Recent studies indicate that the risk of meconium-stained amniotic fluid (MSAF) varies in different ethnic groups. This study prospectively examined the ethnic variation of MSAF and meconium aspiration syndrome, adjusting for gravidity, gestational age (GA), and birth weight. METHOD: The study population consisted of 6901 consecutive live births and included 31 different nationalities, seven main ethnic (race) groups, gravidity between 1 and 19, GA between 22 and 44 weeks, and birth weights between 350 and 6292 gm. RESULTS: The overall incidence of MSAF was 19% (13% thin, 6% thick). The prevalence of meconium aspiration syndrome was 5% in thick MSAF and none in thin MSAF. The incidence of MSAF differs significantly by ethnicity (14% to 30%), gravidity (17% to 23%), GA (6% to 46%), and birth weight (11% to 28%). Multivariate logistic regression analysis using the same variable showed that being black African, post-term, with a gravidity of > or = 7 and a birth weight of > or = 4000 gm significantly increased the chance for MSAF but not meconium aspiration syndrome. After controlling for these clinical variables, the black African infants had a higher percentage of MSAF at all GAs compared with the other ethnic groups. CONCLUSION: This study showed that the risk of MSAF varied by ethnicity and increased with higher gravidity, a GA of > 42 weeks, and a birth weight of > or = 4000 gm The higher incidence of MSAF without an increase in meconium aspiration syndrome in some ethnic groups may indicate advancing maturity of the gastrointestinal system in black ethnic groups compared with others of the same GA.

Amniotic Fluid↗
PubMed1985

Studies on the energy metabolism of the pregnant sow. 1. Uterus and mammary tissue development.

Twenty-six gilts were used in an experiment to study the effects of level of feed intake on the growth and chemical composition of the gravid uterus and mammary tissue at several stages of gestation. The animals were given either 1.8 or 2.5 kg feed/d (20 or 30 MJ metabolizable energy (ME) respectively) and were slaughtered at intervals between days 40 and 110 of gestation. The gravid uterus was dissected into fetal, placental, fluid and empty uterus components. From day 70 of gestation the mammary tissue was also dissected. The fresh weight and dry matter (DM), energy and nitrogen contents of the various tissues were determined. With the exception of the fluid component, there was a significant increase (P less than 0.01) in the fresh weight of each tissue with both stage of gestation and level of feeding. At comparable litter sizes the total weight of the fetuses in late gestation was 16% higher with the higher feed intake. The DM content of the individual uterine tissues increased significantly (P less than 0.01) with increase in stage of gestation so that the mean DM content of the gravid uterus increased from 74.6 g/kg at day 50 to 103.1 and 159.0 g/kg at days 90 and 110 of gestation respectively. Neither stage of gestation nor feeding level influenced the respective energy contents of the individual uterine tissues, when expressed per g DM. The mean energy content of the total gravid uterus was 19.5 kJ/g DM. The N content (g/g fresh weight) of the tissues increased with stage of gestation and was generally higher at the higher feeding level. The mean N contents (g/g DM) of the fetal, placental, fluid and empty uterine tissues were 0.090, 0.101, 0.098 and 0.128 respectively. The mammary tissue was the most variable of all the tissues investigated. Whereas the fresh weight and N content increased with stage of gestation, both the DM and energy content decreased. Gompertz equations were fitted to describe the effects of stage of gestation, level of feed intake and liter size on the fresh weight and chemical content of the individual uterine tissues, total gravid uterus and mammary tissue. The use of these equations for calculating the nutrient requirements of pregnancy is demonstrated. It was calculated that between days 50 and 110 of gestation the ME requirement for reproduction increased from 3 to 12% of maternal energy intake. The calculated requirement for protein was from 7 to 41% of maternal dietary protein intake respectively.

Animals↗
PubMed1996

Reproductive factors and risk of endometrial cancer. The Iowa Women's Health Study.

Gravidity and parity have strong inverse relations with endometrial cancer occurrence. To determine whether gravidity masks an association with other reproductive factors, the authors analyzed data from a cohort study of 24,848 postmenopausal Iowa women aged 55-69 years who were cancer free at baseline in 1986 and who had not had a hysterectomy. During 5 years of follow-up, 167 incident endometrial cancer cases were documented. As expected, the mean gravidity of cases was lower than that of noncases (2.6 vs. 3.5, p < 0.0001). Endometrial cancer occurrence was associated positively with early age at menarche, late age at natural menopause, and total length of ovulation span, but history of infertility and ages at first and last pregnancy were unrelated to risk after adjustment for gravidity. Two additional factors remained statistically significant independent of gravidity: a history of ever (vs. never) having had an induced abortion (relative risk = 2.5, 95% confidence interval 1.1-5.7) and timing of spontaneous abortions (miscarriages). Results suggest that a miscarriage late in reproductive life, followed by lack of a subsequent full-term pregnancy, may be a marker for progesterone deficiency. If so, the findings support the "unopposed" estrogen hypothesis for the etiology of endometrial cancer.

Age Factors↗
PubMed1999

Reduced fertility associated with HIV: the contribution of pre-existing subfertility.

BACKGROUND: HIV-1 infection is associated with lower fertility among women in sub-Saharan Africa and this association is not explained by the frequency of sexual intercourse, illness, knowledge of HIV status or infection with other sexually transmitted diseases. Women with fertility problems are at increased risk of marital instability and, therefore, HIV infection; consequently, pre-existing subfertility among HIV-infected women may contribute to the association. OBJECTIVE: This study examines the relationship between HIV-1 infection and the incidence of recognised pregnancy and the role of low gravidity prior to seroconversion in rural Uganda. METHODS: A group of 176 women (80 HIV infected and 96 uninfected) were enrolled into an HIV-1 natural history cohort and invited to attend 3-monthly clinic appointments. Data from clinic visits were analysed to assess the independent effects of HIV infection and age, lactation, illness, reported frequency of sexual intercourse and sexually transmitted diseases (STD) on the risk of pregnancy in the following 3 months. The number of previous pregnancies was recorded at enrolment, and the effect of gravidity was examined for the subgroup of women who were uninfected at enrolment or who enrolled within 2 years of their estimated seroconversion date. RESULTS: During follow-up, 124 pregnancies were observed in 83 women beginning in the 3 months following 47 (7.0%) of 669 visits made by HIV-infected women and 77 (9.5%) of 812 visits by HIV-negative women (P = 0.12). Adjusting for age, lactation, illness, STD and the reported frequency of sexual intercourse, the estimated reduction in the risk of pregnancy associated with HIV infection was 47% [95% confidence interval (CI) 18-66]. Pre-existing low gravidity was strongly associated with a reduced incidence of pregnancy (odds ratio 0.39; CI 0.19-0.81). Additionally, adjusting for low gravidity reduced the estimate of the effect of HIV infection by almost a half, to 25% (95% CI-57-29). CONCLUSION: Low gravidity prior to seroconversion accounts for almost 50% of the observed association between HIV infection and lowered incidence of pregnancy, after adjusting for age, lactation, illness, STD and the frequency of sexual intercourse.

Adolescent↗
PubMed2000

Reproductive burden, locomotor performance, and the cost of reproduction in free ranging lizards.

A reduction in the locomotor capacity of gravid females is considered to be a cost of reproduction if it leads to an increased risk of mortality. In this study, we measured the change in endurance between gravid and postgravid female side-blotched lizards (Uta stansburiana) as a test of the cost of reproduction. We also altered reproductive investment in some females by direct ovarian manipulation (yolkectomy), which decreased reproductive burden by 30%. Regardless of experimental treatment, all females had lower endurance when gravid. Endurance was 28% lower in gravid females from the yolkectomy treatment and 31% lower in the unmanipulated females relative to postoviposition females. The experimental reduction in clutch mass resulted in a 21% increase in endurance of gravid yolkectomy females relative to control females. Postovipositional endurance was significantly higher in the yolkectomized females than unmanipulated females, which suggests that the cost of reproduction carries over to postoviposition performance. Unmanipulated females exhibited a significant negative association between endurance and size-specific burden. Endurance was not correlated with clutch size or size-specific burden in the yolkectomy females. Survivorship to the second clutch was higher in the yolkectomy females. The results from a logistic regression showed the probability of survival to the second clutch was significantly and positively associated with endurance after controlling for the effects of treatment. Our analyses demonstrated that the decrement in performance associated with current reproductive investment represents a cost of reproduction expressed as diminished locomotor performance and lowered survivorship to the next clutch.

Analysis of Variance↗
PubMed1996

Comparative fecundity and associated factors for two sibling species of the Anopheles gambiae complex occurring sympatrically in The Gambia.

For two sibling species of mosquitoes belonging to the Anopheles gambiae complex of malaria vectors, the effects of body size (wing length) and bloodmeal size (haematin excretion) on fecundity of wild females were investigated in The Gambia, West Africa. Freshly blood-fed individuals from sympatric populations of An.arabiensis and An.gambiae sensu stricto were sampled by collection at 07.00-09.00 hours from within bednets during July/August 1993, at the beginning of the rainy season. The possible confounding effect of infection with Plasmodium parasites was removed by eliminating infected mosquitoes from the study samples. An.arabiensis females comprised 75% of the An.gambiae sensu lato population and were significantly larger (greater mean wing length) than those of An.gambiae s.s. mosquitoes. Mean egg production per female (for the subsequent gonotrophic cycle, excluding pre-gravids) for the two species was not significantly different, though the relationship between wing length and egg production showed An.gambiae s.s. to be more fecund than the An.arabiensis of the same size. Pre-gravid An.gambiae s.s had consumed significantly smaller bloodmeals than gravid females but the mean wing length of these two gonotrophic categories was not significantly different. In contrast, An.arabiensis pre-gravids were smaller and had consumed smaller bloodmeals than the gravids.

Animals↗