Perinatale programmering van volwassen seksueel gedrag en partner preferentie van de rat

Aims of the present study 1. Is adulttestosterone-induced mounting behavior of female rats organized by perinatally circulating testosterone (T)? 2. What role does the prenatal position in utero relative to a brother play in this respect? 3. Is adult partner preference behavior of female rats organized by perinatal T? 4. Is adult partner preference behavior of male rats organized by perinatal T, D HT or E2? 5. What effects do 8-0H-DPAT and yohimbine (well known rat "aphrodisiacs") have on partner preference and sexual behavior in the male rat?In dit proefschrift is geprobeerd antwoorden te vinden op de volgende vragen: 1 Is volwassen door testosteron-geinduceerd beklimgedrag van vrouwelijke ratten op enigerlei wijze geprogrammeerd door perinataai circulerend testosteron (T)? 2 Speelt de prenatale ligging ten opzichte van broertjes hierbij een rol? 3 Wordt de volwassen partner preferentie van vrouwelijke ratten geprogrammeerd door perinataai aanwezig T? 4 Wordt de volwassen partner preferentie van mannelijke ratten geprograrnmeerd door perinataai Ten/of de dihydrotestosteron (DHT) en oestradiol (Ez)? 5 Welke effecten hebben 8-0H-DPAT en yohimbine (bekende ratte-"aphrodisiaca") op partner preferentie en seksueel gedrag van mannelelijke ratten

SDN-POA volume, sexual behavior, and partner preference of male rats affected by perinatal treatment with ATD

The present study investigated 1) the importance of the aromatization process during the perinatal period for the development of the sexually dimorphic nucleus in the preoptic area of the hypothalamus (SDN-POA) of male rats, and 2) the relationship between SDN-POA volume and parameters of masculinization in male rats that were treated perinatally with the aromatase-inhibitor ATD. Males were treated with ATD either prenatally or pre- and neonatally, or with the vehicle. Masculine sexual behavior and partner preference were investigated in adulthood. Thereafter, animals were sacrificed and SDN-POA volume was measured. The SDN-POA volume was reduced in both the prenatally and the pre- and neonatally treated group, with a larger reduction in the latter than in the former group. Combined pre- and neonatal ATD treatment resulted in reduced frequency of mounts, intromissions, and ejaculations, as well as a reduced preference for a female over a male. The SDN-POA size was significantly and positively correlated with frequency of masculine sexual behavior, as well as preference for a female over a male

First trimester employment, working conditions and preterm birth

Objectives To explore the association between working conditions during first trimester and total preterm birth (PTB), and subtypes: spontaneous PTB and iatrogenic PTB, additionally to explore the role of hypertension. Methods Pregnant women from the Amsterdam Born Children and their Development study, filled out a questionnaire between January 2003 and March 2004, two weeks after first prenatal screening (singleton liveborn, n=7561). Working conditions were working hours/week, standing/walking hours/week, physical work load and job strain. Results Prolonged standing/walking during first trimester was associated with an increased risk for total PTB (OR=1.5; 95% CI 1.0-2.3, after adjustments). Other working conditions were not related to total PTB. The separation into spontaneous and iatrogenic PTB revealed that standing/walking was associated with iatrogenic PTB only (OR=2.09; 95% CI 1.00-4.97). The highest risk was found for the combination of a long workweek with high physical work load (OR=3.42; 95% CI 1

The effects of work-related maternal risk factors on time to pregnancy, preterm birth and birth weight: the Generation R Study

Objective To investigate the influence of maternal working conditions on fertility and pregnancy outcomes. Methods 8880 women were enrolled in a large prospective birth cohort during early (76%), mid (21%) or late pregnancy (3%) (61% participation). Complete questionnaire information was available for 6302 women (71% response). Outcomes were prolonged time to pregnancy (TTP) (>6 months), preterm birth (= 5 kg had better fertility and pregnancy outcomes. No self-reported exposure to chemicals was associated with any outcomes and self-assessments had very low reliability compared with JEM-based assessments. JEM-based maternal occupational exposure to phthalates was associated with prolonged TTP (OR 2.16, 95% CI 1.02 to 4.57) and exposure to pesticides was associated with decreased birth weight (OR 2.42, 95% CI 1.10 to 5.34). The population attributable fractions were small at 0.7% for phthalates and 0.7% for pesticides. Conclusion This birth cohort study presents evidence of health-based selection into the workforce and adverse effects of maternal occupational exposure to phthalates and pesticides on fertility and pregnancy outcomes

Physically demanding work, fetal growth and the risk of adverse birth outcomes. The Generation R Study

Objectives Work-related risk factors, such as long work hours, and physically demanding work have been suggested to adversely influence pregnancy outcome. The authors aimed to examine associations between various aspects of physically demanding work with fetal growth in different trimesters during pregnancy and the risks of adverse birth outcomes. Methods Associations between physically demanding work and fetal growth were studied in 4680 pregnant women participating in a population-based prospective cohort study from early pregnancy onwards in the Netherlands (2002-2006). Mothers who filled out a questionnaire during mid-pregnancy (response 77% of enrolment) were included if they conducted paid employment and had a spontaneously conceived singleton live born pregnancy. Questions on physical workload were obtained from the Dutch Musculosk Results There were no consistent significant associations between physically demanding work nor working hours in relation to small for gestational age, low birth weight or preterm delivery. Women exposed to long periods of standing had lower growth rates for fetal head circumference (HC), resulting in a reduction of approximately 1 cm (3%) of the average HC at birth. Compared with women working <25 h/week, women working 25-39 h/week and >40 h/week had lower growth rates for both fetal weight and Conclusion Long periods of standing and long working hours per week during pregnancy seem to negatively influence intrauterine growth

Physically demanding work, fetal growth and the risk of adverse birth outcomes. The Generation R Study

Objectives Work-related risk factors, such as long work hours, and physically demanding work have been suggested to adversely influence pregnancy outcome. The authors aimed to examine associations between various aspects of physically demanding work with fetal growth in different trimesters during pregnancy and the risks of adverse birth outcomes. Methods Associations between physically demanding work and fetal growth were studied in 4680 pregnant women participating in a population-based prospective cohort study from early pregnancy onwards in the Netherlands (2002-2006). Mothers who filled out a questionnaire during mid-pregnancy (response 77% of enrolment) were included if they conducted paid employment and had a spontaneously conceived singleton live born pregnancy. Questions on physical workload were obtained from the Dutch Musculosk Results There were no consistent significant associations between physically demanding work nor working hours in relation to small for gestational age, low birth weight or preterm delivery. Women exposed to long periods of standing had lower growth rates for fetal head circumference (HC), resulting in a reduction of approximately 1 cm (3%) of the average HC at birth. Compared with women working <25 h/week, women working 25-39 h/week and >40 h/week had lower growth rates for both fetal weight and Conclusion Long periods of standing and long working hours per week during pregnancy seem to negatively influence intrauterine growth