A study of selected factors influencing the reproductive performance of the common tern (Sterna hirundo) at Port Colborne, Ontario in 1973 and 1974

Several study areas were investigated at two Port Colborne terneries during the summers of 1973 and 1974 in an attempt to determine the influence of clutch size, time of clutch initiation, position in the colony, proximity to Ring-billed Gulls, vegetation and nesting substrate on the reproductive performance of the Common Tern. Hatching success and reproductive success (the number of chicks fledged per egg laid) were generally higher for 3-egg than 2-egg clutches but fledging (the number of chicks fledged per egg hatched) success was usually independant of clutch size. Hatching, fledging and reproductive success declined as a function of time of clutch initiation. Mean clutch sizes also generally declined as a function of time. Nests located in the center of the colony exhibited higher fledging success than those on the periphery. Rock-based clutches had a lower hatching success than clutches initiated on sand or dried vegetation. Reproductive performance did not appear to be related to proximity to Ring-billed Gulls or vegetation within the study area.

Some factors affecting reproductive success in crossbred dairy cows on smallholder farms in coastal north-east Tanzania

A 2-year longitudinal survey was carried out to investigate factors affecting reproduction in crossbred cows on smallholder farms in and around an urban centre. Sixty farms were visited at approximately 2-week intervals and details of reproductive traits and body condition score (BCS) were collected. Fifteen farms were within the town (U), 23 farms were approximately 5 km from town (SU), and 22 farms approximately 10 km from town (PU). Sources of variation in reproductive traits were investigated using a general linear model (GLM) by a stepwise forward selection and backward elimination approach to judge important independent variables. Factors considered for the first step of formulation of the model included location (PU, SU and U), type of insemination, calving season, BCS at calving, at 3 months postpartum and at 6 months postpartum, calving year, herd size category, source of labour (hired and family labour), calf rearing method (bucket and partial suckling) and parity number of the cow. The effects of the independent variables identified were then investigated using a non-parametric survival technique. The number of days to first oestrus was increased on the U site (p = 0.045) and when family labour was used (p = 0.02). The non-parametric test confirmed the effect of site (p = 0.059), but effect of labour was not significant. The number of days from calving to conception was reduced by hiring labour (p = 0.003) and using natural service (p = 0.028). The non-parametric test confirmed the effects of type of insemination (p = 0.0001) while also identifying extended calving intervals on U and SU sites (p = 0.014). Labour source was again non-significant. Calving interval was prolonged on U and SU sites (p = 0.021), by the use of AI (p = 0.031) and by the use of family labour (p = 0.001). The non-parametric test confirmed the effect of site (p = 0.008) and insemination type (p > 0.0001) but not of labour source. It was concluded that under favourable conditions (PU site, hired labour and natural service) calving intervals of around 440 days could be achieved.

Prevalence of and risk factors for bacterial vaginosis among women of reproductive age attending cervical screening in southeastern Brazil

To determine the prevalence of and risk factors for bacterial vaginosis. A cross-sectional study of women aged 14-54 years attending 18 primary healthcare units in Botucatu, Brazil, for cervical screening was undertaken between September 1, 2012, and January 31, 2013. Data on sociodemographics, sexual behavior, and medical history were obtained by interview. Vaginal swabs were taken to classify the vaginal flora according to the Nugent scoring system. Candida sp. hyphae and infection by Trichomonas vaginalis were also evaluated by microscopy and culture, respectively. Stepwise logistic regression analysis was performed to identify risk factors independently associated with bacterial vaginosis. Among 1519 women included in analyses, 457 (30.1%) had bacterial vaginosis. Variables independently associated with bacterial vaginosis were a single marital status (OR 1.4; 95%CI 1.1-1.8), partner infidelity (OR 1.5; 95%CI 1.2-1.9), abnormal discharge in the previous year (OR 1.5; 95%CI 1.2-2.0), and concurrent trichomoniasis (OR 4.1; 95%CI 1.5-11.5). Current use of hormonal contraception (OR 0.7; 95%CI 0.5-0.9), luteal phase of menstrual cycle (OR 0.8; 95%CI 0.6-0.9), higher income (OR 0.8; 95%CI 0.6-0.9), and vaginal candidiasis (OR 0.5; 95%CI 0.3-0.9) all had protective effects. The prevalence of bacterial vaginosis in the study population is high. The epidemiological data provide evidence of the sexual transmissibility of bacterial vaginosis.

A study of factors regulating the autonomous proliferation of the steroid hormone-induced LJ6195 murine reproductive tract tumor

Neonatal estrogen treatment of BALB/c mice results in the unregulated proliferation of the cervicovaginal epithelium and eventually tumorigenesis. The conversion of the normally estrogen responsive cyclic proliferation of the vaginal epithelium to a continuous estrogen-independent pattern of growth is a complex phenomenon. The aim of this study was to gain an understanding of the mechanism(s) by which steroid hormone administration during a critical period of development alters the cyclic proliferation of vaginal epithelium, ultimately leading to carcinogenesis in the adult animal.^ The LJ6195 murine cervicovaginal tumor was induced by treating newborn female BALB/c mice with 20 $\mu$g 17$\beta$-estradiol plus 100 $\mu$g progesterone for the first 5 days after birth. In contrast to proliferation of the normal vaginal epithelium, proliferation of LJ6195 is not regulated by estradiol. Northern blot analysis of RNA from vaginal tracts of normal mice, neonatal-estrogen treated mice, and LJ6195 indicate that there is an alteration in the expression of several genes such as the estrogen receptor, c-fos, and HER2/neu. In response to neonatal estrogen treatment, the estrogen receptor is down regulated in the murine vaginal tract. Therefore, the estrogen-independent nature of this tissue is established as early as 3 months after treatment. There is strong evidence that the proliferation of LJ6195 is regulated through an autocrine growth pathway. The LJ6195 tumor expresses mRNA for the epidermal growth factor receptor. In addition, conditioned medium from the LJ6195 tumor cell line contains a growth factor(s) with epidermal growth factor-like activity. Conditioned medium from the LJ6195 cell line stimulated the proliferation of the EGF-dependent COMMA D mouse mammary gland cell line in a dose-dependent manner. The addition of an anti-mEGF-antibody to LJ6195 cell cultures significantly decreased growth. These results suggest that the EGF-receptor mediated growth pathway may play a role in regulating the estrogen-independent proliferation of the LJ6195 tumor. ^

Food availability and predation risk, rather than intrinsic attributes are the main factors shaping the reproductive decisions of a long-lived predator

Funded by Natural Research Limited Natural Environment Research Council studentship. Grant Numbers: NE/J500148/1, NE/F021402/1

Factors affecting female reproductive success and the survival of pouch young in the threatened brush-tailed rock-wallaby, Petrogale penicillata

Knowledge of factors affecting the survival of individuals and their reproductive success is essential for threatened species management, but studies assessing these factors are lacking for many threatened rock-wallaby species. In this study we investigated the factors influencing the breeding performance of females and the survival of pouch young in a wild colony of the threatened brush-tailed rock-wallaby. Individuals were trapped between October 2000 and April 2004. More than 50% of the females in the colony were breeding below their full potential and giving birth to only one offspring per year. Most females within the colony bred in synchrony, with a substantial birth peak evident during autumn. Pouch young born in autumn left the pouch during spring and were weaned during summer and autumn when forage was most abundant. Pouch young born during the autumn birth peak or in winter had a substantially higher probability of surviving through to pouch emergence than those born during spring or summer. This study provides demographic parameters that may be used in population models and for comparison with other populations, particularly those that are small and declining. To optimise reproductive success in reintroduction programs, females in good condition and with small pouch young should be released at the end of the wettest season.

Exercise in obese pregnant women: The role of social factors, lifestyle and pregnancy symptoms

Background Physical activity may reduce the risk of adverse maternal outcomes, yet there are very few studies that have examined the correlates of exercise amongst obese women during pregnancy. We examined which relevant sociodemographic, obstetric, and health behaviour variables and pregnancy symptoms were associated with exercise in a small sample of obese pregnant women. Methods This was a secondary analysis using data from an exercise intervention for the prevention of gestational diabetes in obese pregnant women. Using the Pregnancy Physical Activity Questionnaire (PPAQ), 50 obese pregnant women were classified as "Exercisers" if they achieved ≥900 kcal/wk of exercise and "Non-Exercisers" if they did not meet this criterion. Analyses examined which relevant variables were associated with exercise status at 12, 20, 28 and 36 weeks gestation. Results Obese pregnant women with a history of miscarriage; who had children living at home; who had a lower pre-pregnancy weight; reported no nausea and vomiting; and who had no lower back pain, were those women who were most likely to have exercised in early pregnancy. Exercise in late pregnancy was most common among tertiary educated women. Conclusions Offering greater support to women from disadvantaged backgrounds and closely monitoring women who report persistent nausea and vomiting or lower back pain in early pregnancy may be important. The findings may be particularly useful for other interventions aimed at reducing or controlling weight gain in obese pregnant women.

Fertility and infertility : studies in reproductive epidemiology in Australia

Worldwide, there are few large-scale epidemiological studies on infertility. In Australia, population-based research on infertility is limited to a few small-scale studies. Therefore, the prevalence of infertility and unmet need for specialist medical advice and treatment cannot be estimated reliably. Women who have used assisted reproductive technologies (ART) are recorded in treatment registries. However, there are many infertile women who are excluded from these clinical populations because they neither seek advice nor use treatment. The thesis was based on a biopsychosocial model of health and used the methods of reproductive epidemiology to address the lack of national data on the prevalence of infertility in Australia. Firstly, numbers of births and pregnancy losses were investigated in two generations of women participating in the Australian Longitudinal Study on Women’s Health (ALSWH). The ALSWH is a broad-ranging, longitudinal examination of biological, psychological and social factors that impact on women’s health and wellbeing. Women from three age cohorts were randomly sampled from the population using the universal public health insurance (i.e., Medicare) database and ALSWH participants were representative of the female population. However, the studies in the thesis only involved data from two cohorts. The younger cohort were born in 1973-78 and completed up to four mailed surveys between 1996 (when they were aged 18-23 years, n=14247) and 2006 (28-33 years, n=9145). The mid-aged cohort were born in 1946-51 and completed four mailed surveys between 1996 (when they were aged 45-50 years n=13715) and 2004 (53-58 years, n=10905). Compared to other studies that focus on outcomes of single pregnancies, these studies included all pregnancy outcomes by developing comprehensive reproductive histories for each woman. Pregnancy outcomes included birth, miscarriage, stillbirth, termination and ectopic pregnancy. Women in the youngest cohort (born in 1973-78) were only just reaching their peak childbearing years and many (44%) had yet to report their first pregnancy outcome. Women from the mid-aged cohort (born 1946-51) had completed their reproductive lives and 92% were able to report on their lifetime pregnancy outcomes. Pregnancy losses, especially miscarriage, were common for both generations of women. Secondly, the prevalence of infertility, seeking medical advice and using treatment was identified for these two generations of women. For the older generation, the lifetime prevalence of infertility and demand for treatment was investigated in the context of the specialist medical services which became available circa 1980. By this time, however, most of these older women had already been pregnant and completed their families. For women who experienced infertility (11%), their options for advice and treatment were limited and less than half (42%) had used any treatment. More recently for the younger generation of women, who were aged 28-33 years in 2006, specialist advice and treatment were extensively available. Among women who had tried to conceive or had been pregnant (n=5936), 17% had experienced infertility and the majority (72%) were able to access medical advice. However, after seeking advice only half of these infertile women had used treatment with fertility hormones or in vitro fertilisation (IVF). Overall for infertile women aged up to 33 years, only one-third had used these treatments. Thirdly, the barriers to accessing medical advice and using treatment for infertility were identified for women aged less than 34 years. Among a community sample of infertile women aged 28-33 years (ALSWH participants), self-reported depression was found to be a barrier to accessing medical advice. The characteristics of these infertile women in the community who had (n=121) or had not (n=110) used treatment were compared to infertile women aged 27-33 years (n=59) attending four fertility clinics. Compared to infertile women in the community, living in major cities and having private health insurance were associated with early use of treatment for infertility at specialist clinics by women aged <34 years. In contrast to most clinical studies of IVF, the final study reported in the thesis took into account repeated IVF cycles and the impact of women’s individual histories on IVF outcomes. Among 121 infertile women (aged 27-46 years) who had 286 IVF cycles, older age and prolonged use of the oral contraceptive pill were associated with fewer eggs collected. Further, women in particular occupations had lower proportions of eggs fertilised normally than women in other occupational groups. These studies form the first large-scale epidemiological examination of infertility in Australia. The finding that two-thirds of women with infertility had not used treatment indicates that there is an unmet need for specialist treatment in women aged less than 34 years. However, barriers to accessing treatment prevent women using ART at a younger age when there is a higher chance of pregnancy.

Vaccination to protect against infection of the female reproductive tract

Infection of the female genital tract can result in serious morbidities and mortalities from reproductive disability, pelvic inflammatory disease and cancer, to impacts on the fetus, such as infant blindness. While therapeutic agents are available, frequent testing and treatment is required to prevent the occurrence of the severe disease sequelae. Hence, sexually transmitted infections remain a major public health burden with ongoing social and economic barriers to prevention and treatment. Unfortunately, while there are two success stories in the development of vaccines to protect against HPV infection of the female reproductive tract, many serious infectious agents impacting on the female reproductive tract still have no vaccines available. Vaccination to prevent infection of the female reproductive tract is an inherently difficult target, with many impacting factors, such as appropriate vaccination strategies/mechanisms to induce a suitable protective response locally in the genital tract, variation in the local immune responses due to the hormonal cycle, selection of vaccine antigen(s) that confers effective protection against multiple variants of a single pathogen (e.g., the different serovars of Chlamydia trachomatis) and timing of the vaccine administration prior to infection exposure. Despite these difficulties, there are numerous ongoing efforts to develop effective vaccines against these infectious agents and it is likely that this important human health field will see further major developments in the next 5 years.

Reproductive health: findings from the Australian Longitudinal Study on Women’s Health. Chapter 5: fertility and infertility

Chapter 5: Fertility and infertility. p52-70. This section describes patterns of fertility across Surveys 1 to 4 among the cohort of women who were born in 1973-1978. This section includes the examination of pregnancy outcomes including both live births and pregnancy losses (stillbirths, miscarriages, terminations and ectopic pregnancies). This section also examines the prevalence of self-reported problems with fertility and whether these women sought advice and/or treatment. As women age they are more likely to experience infertility and, with little other data available, the ALSWH provides an important opportunity to examine this problem and the related use of health services. 1. Pregnancy losses are common. Half of the women who report a pregnancy outcome at Survey 4 have experienced a pregnancy loss. 2. More than one third (39%) of women who have experienced a live birth by Survey 4 have also experienced a pregnancy loss. 3. For every ten women aged 28-33 years in 2006: four women had not had been pregnant, five women had a live birth (with or without a recognised pregnancy loss), and one woman had a recognised pregnancy loss only. 4. Among women who had tried to conceive or had been pregnant, one-in-six had experienced infertility. (i.e. tried unsuccessfully to get pregnant for 12 months or more) 5. The most significant factors associated with having infertility, seeking advice and using treatment were: polycystic ovary syndrome, endometriosis and miscarriage. 6. Of the women who reported infertility, two-thirds sought advice but only half used treatment. 7. Most of the women who used fertility treatment had used low cost and non-invasive methods.