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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!




Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System


Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.

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Pregnancy Timeline by SemestersDevelopmental TimelineFertilizationFirst TrimesterSecond TrimesterThird TrimesterFirst Thin Layer of Skin AppearsEnd of Embryonic PeriodEnd of Embryonic PeriodFemale Reproductive SystemBeginning Cerebral HemispheresA Four Chambered HeartFirst Detectable Brain WavesThe Appearance of SomitesBasic Brain Structure in PlaceHeartbeat can be detectedHeartbeat can be detectedFinger and toe prints appearFinger and toe prints appearFetal sexual organs visibleBrown fat surrounds lymphatic systemBone marrow starts making blood cellsBone marrow starts making blood cellsInner Ear Bones HardenSensory brain waves begin to activateSensory brain waves begin to activateFetal liver is producing blood cellsBrain convolutions beginBrain convolutions beginImmune system beginningWhite fat begins to be madeHead may position into pelvisWhite fat begins to be madePeriod of rapid brain growthFull TermHead may position into pelvisImmune system beginningLungs begin to produce surfactant
CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development


More precise due dates for average pregnancy?

To the frustration of busy pregnant women everywhere, the estimate of when she'll actually give birth can be off by as much as two to three weeks — early or late. Now, a routine screening could help narrow the estimated date of delivery to seven days from the time of the test.

Women often have a window of more than a month in which carefully laid plans can be thrown into disarray. Only 5 percent of women deliver exactly on their due date. A new meta-analysis suggests that one routine screening test could help mothers narrow that window to seven days from the time of her test.

The research was published October 28th in BJOG: An International Journal of Obstetrics and Gynaecology.

"Measuring cervical length via ultrasound at around 37-39 weeks can give us a better sense of whether a mother will deliver soon — or not."

Vincenzo Berghella MD, Director of Maternal Fetal Medicine at Thomas Jefferson University Hospital, Professor of Obstetrics and Gynecology, Sidney Kimmel Medical College at Thomas Jefferson University and senior author.

Until now, measuring cervical length has been used to help detect women with a high chance of premature labor - the shorter the cervix, the more likely labor is imminent.

Since the method is considered the gold standard for detecting preterm birth, a number of researchers have investigated whether it could be used to help predict birth at term as well. The results have produced debate in the field, with some studies showing poor predictive value, others showing stronger value. Dr. Berghella and colleagues' aim was to pool the data from comparable studies using transvaginal ultrasound to test cervical length, and come to a consensus.

Researchers pooled data from five prospective studies. These included 735 women with single-child pregnancies in the proper head-down position.

Researchers found that when the cervix measured more than 30 millimeters at a woman's due date, she had less than a 50 percent chance of delivering within seven days.

However, when the cervix measures 10 mm or less, a woman had more than an 85 percent chance of delivering within seven days.

Cervical length is a good predictor because it tracks the natural progress of a woman's body toward labor.

When a woman's body prepares for labor, a number of changes start to take place. The cervix, which has kept the baby from descending down the birth canal for the nine months of pregnancy, begins to soften. It changes its usual "ice cream cone" shape — when an ice cream cone is held upright — to a shorter cone with a flattened top pressing against the curve of the uterus.

When the process begins too early, it signals a preterm birth, which caught in time can be delayed with medications.

"Women always ask for a better sense of their delivery date in order to help them prepare for work leave, or to make contingency plans for sibling-care during labor. These are plans which help reduce a woman's anxiety about the onset of labor.

"But having a better sense can also help obstetricians provide information that could help improve or even save a mother or baby's life. For example, women with a higher risk of stillbirth may be better off receiving labor induction. If the cervix is still long at her due date, the chances of timely spontaneous birth are low.

Dr. Berghella

The possibility to predict the delivery date is a question frequently raised by pregnant women. However, a clinician has currently little to predict when a woman at term will deliver.

To evaluate the predictive accuracy of transvaginal ultrasound (TVU) cervical length (CL) for spontaneous onset of labour in singleton gestation enrolled at term by a meta-analysis.

Search strategy
We performed a literature search in electronic databases.

Selection criteria
We included only studies assessing the accuracy of TVU CL in prediction of spontaneous onset of labour in singleton gestations with vertex presentation who were enrolled at term.

Data collection and analysis
The primary outcome was the accuracy of CL for prediction of spontaneous labour within 7 days. Pooled sensitivities and specificities were calculated.

Main results
Five studies including 735 singleton gestations were included. For the prediction of spontaneous labour within 7 days for CL <30 mm the pooled sensitivity was 64% and pooled specificity was 60%. The higher the CL, the better the sensitivity; the lower the CL, the better the specificity. A woman with a singleton gestation at term and a TVU CL of 30 mm has a <50% chance of delivering within 7 days, while one with a TVU CL of 10 mm has an over 85% chance of delivery within 7 days.

TVU CL at term has moderate value in predicting the onset of spontaneous labour. A woman with a TVU CL of 10 mm or less has a high chance of delivering within a week.

The authors report no conflicts of interest.

Article Reference: G. Saccone et al., "Transvaginal ultrasound cervical length for prediction of spontaneous labor at term: a systematic review and meta-analysis," BJOG, DOI: 10.1111/1471-0528.13724, 2015.

About Jefferson -- Health is all we do.
Our newly formed organization, Jefferson, encompasses Thomas Jefferson University and Jefferson Health, representing our academic and clinical entities. Together, the people of Jefferson, 19,000 strong, provide the highest-quality, compassionate clinical care for patients, educate the health professionals of tomorrow, and discover new treatments and therapies that will define the future of health care.

For more information and a complete listing of Jefferson services and locations, visit http://www.jefferson.edu.

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Nov 5, 2015   Fetal Timeline   Maternal Timeline   News   News Archive   

In late term pregnancy, the cervix will be stretched and located lower in the
pelvic region after displacement by the growing uterus holding the fetus.
Image Credit: MouseWorks











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