Listar Producción científica por autor "Thornburg, Jonathan"
Mostrando ítems 1-6 de 6
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A prospective study of early pregnancy loss in humans
Vitzthum, Virginia J; Spielvogel, Hilde; Thornburg, Jonathan; Brady West, MA (Fertility and Sterility, 2006-08)Objective: To test two hypotheses: In spontaneous conceptions, early pregnancy loss (EPL) is associated with [1] inadequate luteal (ovarian) P, and/or [2] elevated follicular (adrenal) P. Design: A population-based ... -
Interpopulational differences in progesterone levels during conception and implantation in humans
Vitzthum, Virginia J; Spielvogel, Hilde; Thornburg, Jonathan (PNAS, 2004-02-10)Clinical studies of women from the United States demonstrate a sensitivity of the ovarian system to energetic stress. Even moder ate exercise or caloric restriction can lead to lower progesterone levels and failure to ... -
New data demonstrates that relationship of salivary to serum progesterone in Bolivian women is comparable to that in other populations
Thornburg, Jonathan; Bellido, Diva; Stewart, Rose; Spielvogel, Hilde; Echalar, Lourdes; Burch, Jennifer; Vitzthum, Virginia J (36th Annual Meeting Minnesota, 2011-04-13)Abstract. Salivary progesterone (P) concentration is widely used in field studies as a relatively easy-to-measure proxy for serum P. Chatterton et al. [Fertility & Sterility 86:723 (2006)] compared sample means of ... -
Salivary progesterone levels and rate of ovulation are significantly lower in poorer than in better-of urban-dwelling Bolivian women
Vitzthum, Virginia J; Bentley, Gillian R; Spielvogel, Hilde; Cáceres, Esperanza; Thornburg, Jonathan; Jones, Lary; Shore, Sarah; Hodges, Kelly R; Chatterton, Robert T (Human Reproduction, 2002)Agriculturalists in less-developed countries (LDC) have lower progesterone levels than urban industrialized populations. However, it is unknown if urban LDC populations are also relatively lower. We tested whether urban ... -
Seasonal and circadian variation in salivary testosterone in rural Bolivian men
Vitzthum, Virginia J; Worthman, Carol M; Beall, Cynthia M; Thornburg, Jonathan; Vargas, Enrique; Villena, Mercedes; Soria Sánchez, Rudy; Cáceres, Esperanza; Spielvogel, Hilde (American Journal of Human Biology, 2009-02-19)Abstract. Testosterone (T) plays a key role in the increase and maintenance of muscle mass and bone density in adult men. Life history theory predicts that environmental stress may prompt a reallocation of such investments ... -
Seasonal modulation of reproductive effort during early pregnancy in humans
Vitzthum, Virginia J; Thornburg, Jonathan; Spielvogel, Hilde (American Journal of Human Biology, 2009-03-03)Abstract. Life history theory predicts that early pregnancy presents a relatively low cost, uncontested opportunity for a woman to terminate investment in a current reproductive opportunity if a conceptus is of poor quality ...