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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.

WHO International Clinical Trials Registry Platform

The World Health Organization (WHO) has created a new Web site to help researchers, doctors and
patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!




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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 July 3, 2013

ICSI procedure
Intracytoplasmic Sperm Injection (ICSI)

Male infertility accounts for nearly a third of all cases of infertility, including:
azoospermia (rare, complete absence of sperm in ejaculate), low sperm count,
and abnormal sperm. IVF with ICSI may be recommended if there is any concern
about the availability or quality of a male’s sperm. ICSI has revolutionized the
treatment of male infertility since it allows couples to achieve fertilization,
even when very small quantities sperm are available.

WHO Child Growth Charts




IVF increases small risk for mental retardation

In a study that included more than 2.5 million children born in Sweden, compared with spontaneous conception, any in vitro fertilization (IVF) treatment was not associated with autistic disorder — but was associated with a small, but statistically significantly increased risk of mental retardation.

The study appears in the July 3 issue of JAMA. The authors note that the prevalence of these disorders was low, and the increase in absolute risk associated with IVF was small.

"Between 1978 and 2012, approximately 5 million infants worldwide were born from in vitro fertilization," according to background information in the article. "No study has investigated the association between different IVF procedures and neurodevelopment, and few studies have investigated whether IVF treatments are associated with neurodevelopment after the first year of life.

Few studies have looked at autistic disorder and mental retardation, 2 of the most severe chronic developmental disorders, affecting 1 percent to 3 percent of all children in developed countries."

Sven Sandin, M.Sc., of King's College London, and colleagues examined the association between use of any IVF and different IVF procedures and the risk of autistic disorder and mental retardation in the offspring. Using Swedish national health registers, offspring born between 1982 and 2007 were followed up for a clinical diagnosis of autistic disorder or mental retardation until December 2009. The exposure of interest was IVF, categorized according to whether intracytoplasmic sperm injection (ICSI) for male infertility was used and whether embryos were fresh or frozen.

A total of 2,541,125 children were alive at 1.5 years of age and had complete data on all the covariates; 30,959 (1.2 percent) were born following an IVF procedure. Autistic disorder was diagnosed in 103 of 6,959 children (1.5 percent) and mental retardation in 180 of 15,830 children (1.1 percent) who were born after an IVF procedure. Cases had an average follow-up time of 10 years, median (midpoint) 14 years.

Analysis of the data indicated that compared with spontaneous conception, any IVF treatment was not associated with autistic disorder but was associated with a small but statistically significantly increased risk of mental retardation, although when restricted to singletons (single births), the risk for mental retardation was no longer statistically significant. "However, the results demonstrated an association between autistic disorder and mental retardation and specific IVF procedures with ICSI related to paternal origin of infertility compared with IVF without ICSI," the authors write.

"The prevalence of these disorders was low, and the increase in absolute risk associated with IVF was small. These associations should be assessed in other populations."


"To the best of our knowledge, this is the largest study examining the relationship between specific IVF procedures and autistic disorder and mental retardation, examining the full range of IVF procedures. Our results should be applicable to most countries where IVF and ICSI are used. There are no major differences in equipment or laboratory work across countries but there may be some differences in choice of procedure. For instance, in several countries (like the United States), ICSI is often used when the sperm sample is normal because of a presumed (but unproven) higher efficiency. Blastocyst [a structure in early embryonic development that contains a cluster of cells] transfer is infrequently used in Sweden but is more common in the United States."

This study was funded by Autism Speaks and the Swedish Research Council. Dr. Illiadou was supported by a grant from EU-FP7 HEALTH. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.

Editorial: In Vitro Fertilization and Risk of Autistic Disorder and Mental Retardation

Marcelle I. Cedars, M.D., of the University of California-San Francisco, comments on the findings of this study in an accompanying editorial.

"The study by Sandin et al has sufficient numbers of IVF procedures and outcomes and detailed information to address questions regarding specific aspects of IVF that may pose special risk. Even though the data are reassuring regarding the absence of risk of autistic disorder and the small absolute risk of mental retardation with IVF, continued study of the implications of ovarian stimulation, embryo culture, and multiple embryo transfer is required. The number of children born as a result of IVF will continue to increase and much remains to be learned about the long-term implications. Understanding and eliminating even a small risk of neurodevelopmental impairment are important goals."

The author has completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.

Original press release:http://www.kcl.ac.uk/iop/news/records/2013/April/Epigenetics-autism.aspx