Welcome to The Visible Embryo
Home-- -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- -Contact

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

Contact The Visible Embryo

News Alerts Archive

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.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.


Developmental 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
Pregnancy Timeline by Semesters

Developmental Timeline Fertilization First Trimester Second Trimester Third Trimester First Thin Layer of Skin Appears End of Embryonic Period End of Embryonic Period Female Reproductive System Beginning Cerebral Hemispheres A Four Chambered Heart First Detectable Brain Waves The Appearance of Somites Basic Brain Structure in Place Heartbeat can be detected Heartbeat can be detected Finger and toe prints appear Finger and toe prints appear Fetal sexual organs visible Brown fat surrounds lymphatic system Bone marrow starts making blood cells Bone marrow starts making blood cells Inner Ear Bones Harden Sensory brain waves begin to activate Sensory brain waves begin to activate Fetal liver is producing blood cells Brain convolutions begin Brain convolutions begin Immune system beginning White fat begins to be made Head may position into pelvis White fat begins to be made Period of rapid brain growth Full Term Head may position into pelvis Immune system beginning Lungs begin to produce surfactant
Google Search artcles published since 2007

Home | Pregnancy Timeline | News Alerts |News Archive May 25, 2015

Women born preterm have a higher risk of giving birth preterm, according to
research from the University of Montreal. Researchers demonstrated 13%
of women themselves born before 37 weeks - or term - gave birth prematurely
at least once, compared to 9.5 percent of women born at term - 37 wks+.
Image Credit: Sarah Hopkins. CC BY ND 2.0





Risk of preterm delivery for women born preterm

Women who were born preterm have a higher risk of giving birth to preterm children, according to a study from researchers of the CHU Sainte-Justine and the University of Montreal.

Researchers have uncovered that 13% of women who were born before 37 weeks of gestation — gave birth prematurely to at least one child as compared to 9.5% of women born at full term or 37 to 40 weeks. Interestingly, this number increased to 14% in women who were born before 32 weeks.

"The difference is not alarming considering that the vast majority of women born preterm gave birth at term. But it is significant enough to consider preterm birth a risk factor in monitoring pregnancies."

Anne Monique Nuyt MD, senior author.

The article was published online in the journal Obstetrics and Gynecology on April 7, 2015.

Until now, it was known that low birth weight increased the risk of preterm delivery. But what about babies whose weights are low but within normal for preemies? "Our findings are unequivocal. The simple fact of being born prematurely increases the risk of premature delivery," said Ariane Boivin PhD, the lead author. She adds that they analyzed data from a cohort of 7,405 Quebec women born preterm over a period of 19 years - 1976 to 1995 - and compared their deliveries to women born at term.

Preventing prematurity is one of the intentions of the research.

"Knowing that being born preterm is a risk factor for expectant mothers, obstetricians could inform their patients of the warning signs, so they can be vigilant and respond quickly if contractions occur," added Dr. Nuyt. Some of her colleagues are working on developing drugs to prevent prematurity in order to allow the fetus as much time as possible to develop normally in the womb.

"Having established with certainty a link between preterm birth and preterm delivery encourages us to continue our work to understand the underlying biological and genetic mechanisms, that could one day prevent premature labor from occurring,"
she concludes.

Her article "Risk for Preterm and Very Preterm Delivery in Women Who Were Born Preterm" was published online in the journal Obstetrics and Gynecology on April 7, 2015.

OBJECTIVE: To evaluate whether women who themselves were born preterm are at increased risk of preterm delivery and, if so, whether known maternal complications of preterm birth such as hypertension or diabetes explain this risk.

METHODS: We conducted a population-based cohort study of all women born preterm (51,148) and term (823,991) in Québec, Canada, between 1976 and 1995; after frequency matching 1:2 preterm to term, we examined the relationship of preterm birth between women and their offspring.

RESULTS: The study included 7,405 women who were born preterm (554 before 32 weeks of gestation and 6,851 at 32–36 weeks of gestation) and 16,714 women born term, who delivered 12,248 and 27,879 newborns, respectively. Overall, 14.2% of women born before 32 weeks of gestation, 13.0% of 32–36 weeks of gestation, and 9.8% of those born term delivered prematurely at least once during the study period, including 2.4%, 1.8%, and 1.2%, respectively, who delivered very preterm (both P<.001 for trend). After adjustment for factors including own birth weight for gestational age and pregnancy complications, the overall odds of preterm first live delivery associated with being born preterm was elevated by 1.63-fold (95% confidence interval [CI] 1.22–2.19) for women born before 32 weeks of gestation and 1.41-fold (95% CI 1.27–1.57) for those born at 32–36 weeks of gestation relative to women born term.

CONCLUSION: Women who themselves were born preterm are at increased risk of delivering their neonates prematurely. This is independent of prematurity risks associated with hypertension and diabetes.

The authors highlight the collaboration of the Institut de la statistique du Québec in collecting and analyzing the data. Anne Monique Nuyt is a neonatologist at CHU Sainte-Justine, researcher and head of the Fetomaternal and Neonatal Pathologies research axis at the CHU Saint-Justine Research Center, and professor at the Department of Pediatrics, University of Montreal. Ariane Boivin conducted this research study as part of her postdoctoral work under the supervision of Dr. Nuyt. The University of Montreal is officially known as Université de Montréal.

Return to top of page