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Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than one million visitors each month.

Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

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Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development
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Home | Pregnancy Timeline | News Alerts |News Archive Aug 27, 2014

Environmental exposure to endocrine-disrupting chemicals such as phthalates could
be contributing to the trend of declining testosterone and related disorders.

 






WHO Child Growth Charts

 

 

 

Phthalates in plastics can block testosterone

Phthalates found in plastics could block hormone involved in sexual function, bone density, and cognitive function.

Men, women and children exposed to high levels of phthalates — endocrine-disrupting chemicals found in plastics and some personal care products — have reduced levels of testosterone in their blood, according to a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

Testosterone is the main sex hormone in men. But, it contributes to a variety of functions in both sexes, including physical growth and strength, brain function, bone density and cardiovascular health. In the last 50 years, research has identified a trend of declining testosterone in men and a rise in related health conditions, including reduced semen quality in men and genital malformations in newborn boys.

Animal and cellular studies have found that some phthalates block the effects of testosterone on the body's organs and tissues. Researchers set out to examine whether these chemicals, which are widely used in flexible PVC plastics and personal care products, had a similar effect in humans.


"We found evidence reduced levels of circulating testosterone were associated with increased phthalate exposure in several key populations, including boys ages 6-12, and men and women ages 40-60.

"This may have important public health implications, since low testosterone levels in young boys can negatively impact reproductive development, and in middle age can impair sexual function, libido, energy, cognitive function and bone health in men and women."

John D. Meeker, MS, ScD, of the University of Michigan School of Public Health in Ann Arbor, MI, one of the study authors.


The cross-sectional study examined phthalate exposure and testosterone levels in 2,208 people who participated in the U.S. National Health and Nutrition Examination Survey, 2011-2012. Researchers analyzed urine samples to measure concentrations of 13 substances left after the body metabolizes phthalates. Each participant's testosterone level was measured using a blood sample.


Researchers find an inverse relationship between phthalate exposure and testosterone at various life stages.

Increased Phthalates Resulted In
Women 40-60 10.8 to 24% less testosterone
Boys 6-12 24 to 34.1% less testosterone

"While the study's design limits the conclusions we can draw, our results support the hypothesis that environmental exposure to endocrine-disrupting chemicals such as phthalates could be contributing to the trend of declining testosterone and related disorders," Meeker added. "With mounting evidence for adverse health effects, individuals and policymakers alike may want to take steps to limit human exposure."

Objective:
To explore relationships between urinary concentrations of 13 phthalate metabolites and serum total T levels among men, women, and children when adjusting for important confounders and stratifying by sex and age (6–12, 12–20, 20–40, 40–60, and 60–80 y).

Results:
Multiple phthalates were associated with significantly reduced T in both sexes and in differing age groups. In females, the strongest and most consistent inverse relationships were found among women ages 40–60 years. In boys 6–12 years old, an interquartile range increase in metabolites of di-2-ethylhexyl phthalate was associated with a 29% (95% confidence interval, 6, 47) reduction in T. In adult men, the only significant or suggestive inverse associations between phthalates (metabolites of di-2-ethylhexyl phthalate and dibutyl phthalate) and T were observed among men ages 40–60 years.

Meeker and Kelly K. Ferguson, PhD, of the University of Michigan School of Public Health, are the authors of the study.

The study, "Urinary Phthalate Metabolites are Associated with Decreased Serum Testosterone in Men, Women and Children from NHANES 2011-2012," was published online, ahead of print.

Founded in 1916, the Endocrine Society is the world's oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, the Endocrine Society's membership consists of over 17,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied and clinical interests in endocrinology. The Endocrine Society is based in Washington, DC. To learn more about the Society and the field of endocrinology, visit our site at http://www.endocrine.org. Follow us on Twitter at https://twitter.com/#!/EndoMedia.



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