Life is all about tradeoffs and recently published research by Virginia J. Vitzthum, a senior scientist at Indiana University's Kinsey Institute for Research in Sex, Gender, and Reproduction, and professor in the IU College of Arts and Sciences' Department of Anthropology, has shown that during periods of intense labor and low food intake, rates of early pregnancy loss can more than double.
The findings, reported recently in the American Journal of Human Biology, are the first to show seasonality of early pregnancy loss in a non-industrialized population -- in this case rural Bolivian women -- and the first to demonstrate a relationship between economic activities and early pregnancy loss.
Vitzthum's research challenges the past belief that nearly all early pregnancy losses are caused by genetic defects in the embryo. Genetic defects wouldn't change with the seasons, so Vitzthum's findings show that environmental factors must also play a major role in early pregnancy losses.
"This finding applies to U.S. moms just as much as Bolivians, and it applies to psychosocial resources just as much as food supply," Vitzthum said. "As well as healthy food, pregnant women also need good working conditions and adequate social support from family, friends and workplace to keep their risks of early pregnancy losses low."
Men are affected, too. In a second research paper, also published in the "American Journal of Human Biology," Vitzthum reports a similar relationship between reproductive fitness and external influences.
"This paper also concerns the effects of limited resources, this time on male physiology," she said. "In the worst part of the year, late winter, testosterone levels are suppressed. This is particularly interesting because it had been thought that males were much less sensitive, if at all, to environmental conditions because they don't need a lot of energy for a pregnancy. The effects of poor resources on males appear to be more subtle but can still be important for their own health and well being."
Vitzthum's work has long been at the crossroads of biology and culture, focusing on how human reproductive functioning has evolved in response to different environmental conditions.
"Until recently, it was assumed that women everywhere had similar reproductive biology," she said. "We now know that women vary tremendously, and these differences affect women's health."
One example is how high hormone levels increase the risk of breast cancer and other diseases. By studying the international patterns of hormone levels and how they relate to different environmental conditions, Vitzthum hopes to learn more about which women are at the greatest risks for these diseases. Doctors could then recommend extra monitoring or screening tests for those women.
Coauthors for "Seasonal Modulation of Reproductive Effort During Early Pregnancy in Humans," includes Jonathan Thornburg, Indiana University; and Hilde Spielvogel, Universidad Mayor de San Andres, Bolivia. It was supported by the National Science Foundation and the University of California.
Coauthors of "Seasonal and Circadian Variation in Salivary Testosterone in Rural Bolivian Men," include Carol M. Worthman, Emory Univesity; Cynthia M. Beall, Case Western Reserve; Jonathan Thornburg, Indiana University; and Enrique Vargas, Mercedes Villena, Rudy Soria, Esperanza Caceres and Hilde Spielvogel, of the Universidad Mayor de San Andres in Bolivia. It was supported by the NSF, National Institutes of Mental Health and the University of California Regents.
To speak with Vizthum or for additional assistance, contact Steve Chaplin, University Communications, at 812-856-1896 or email@example.com. Top
Journal citations: "Seasonal Modulation of Reproductive Effort During Early Pregnancy in Humans," American Journal of Human Biology, 2009 Jul-Aug;21(4):548-58; "Seasonal and Circadian Variation in Salivary Testosterone in Rural Bolivian Men," American Journal of Human Biology, published online in April, 2009.
Steve Chaplin | EurekAlert!
Drought hits rivers first and more strongly than agriculture
06.09.2018 | Max-Planck-Institut für Biogeochemie
Landslides triggered by human activity on the rise
23.08.2018 | European Geosciences Union
Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.
"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...
A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.
Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...
Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.
An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...
Graphene is considered a promising candidate for the nanoelectronics of the future. In theory, it should allow clock rates up to a thousand times faster than today’s silicon-based electronics. Scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) and the University of Duisburg-Essen (UDE), in cooperation with the Max Planck Institute for Polymer Research (MPI-P), have now shown for the first time that graphene can actually convert electronic signals with frequencies in the gigahertz range – which correspond to today’s clock rates – extremely efficiently into signals with several times higher frequency. The researchers present their results in the scientific journal “Nature”.
Graphene – an ultrathin material consisting of a single layer of interlinked carbon atoms – is considered a promising candidate for the nanoelectronics of the...
03.09.2018 | Event News
27.08.2018 | Event News
17.08.2018 | Event News
19.09.2018 | Life Sciences
19.09.2018 | Physics and Astronomy
19.09.2018 | Information Technology