Welcome to The Visible Embryo
The Visible Embryo Home
Home--- -History-----Bibliography-----Pregnancy Timeline-----Prescription Drugs in Pregnancy---- Pregnancy Calculator----Female Reproductive System----News----Contact
WHO International Clinical Trials Registry Platform

The World Health Organization (WHO) has a Web site to help researchers, doctors and patients obtain information on clinical trials. Now you can search all such registers to identify clinical trial research 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.

Content protected under a Creative Commons License.
No dirivative works may be made or used for commercial purposes.


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


Born to run?

A new study suggests love of exercise starts in the womb. Baylor College of Medicine research has found that female mice that voluntarily exercise during pregnancy, have pups more physically active as adults.

Robert A. Waterland PhD, associate professor of pediatrics - nutrition and of molecular and human genetics — noted that although their research studied mice, "several human studies have reported results consistent with ours." Dr. Waterland is at the U.S. Department of Agriculture/Agricultural Research Service (USDA/ARS) Children's Nutrition Research Center, Baylor and Texas Children's Hospital and senior author of this work.

The research appears in The FASEB Journal.

Observational studies have found that women who are physically active when they are pregnant, have children who tend to be more physically active. But these results could be attributed to the mothers' influence on the children after they were born. Or, mothers could pass to their offspring a genetic predisposition to be physically active.

"Our study in a mouse model is important because we can take all those effects out of the equation. We studied genetically identical mice and carefully controlled the amount of physical activity of the mothers before pregnancy," said Waterland.

The Baylor team selected female mice that all enjoyed running. Then they divided them into two groups. One was allowed access to running wheels before and during pregnancy, and the other was not.

During early pregnancy, the females with running wheels ran an average of 10 kilometers or 6.21 miles a night. They ran less as pregnancy progressed, but even by the beginning of the third trimester they ran (or walked) about 3 kilometers or 1.86 miles each night.

Researchers found mice born to mothers that exercised during pregnancy were about 50 percent more physically active than those born to mothers who did not exercise.

Importantly, their increased activity persisted into later adulthood, and even improved their ability to lose fat during a three-week voluntary exercise program.

This study supports the idea that movement during pregnancy influences fetal brain development, making offspring tend to be more physically active throughout life.

"Although most people assume that an individual's tendency to be physical active is determined by genetics, our results clearly show that the environment can play an important role during fetal development."

Robert A. Waterland PhD, Associate Professor of Pediatrics - Nutrition and of Molecular and Human Genetics, Children's Nutrition Research Center, Baylor and Texas Children's Hospital, and senior author.

If a similar effect can be confirmed in people, it could represent an effective strategy to counteract the current worldwide epidemic of physical inactivity and obesity.

Increasing physical activity has major health implications. According to the World Health Organization, insufficient physical activity is one of the 10 leading risk factors for death worldwide.

Several expert groups including the American College of Obstetricians and Gynecologists already recommend that, in the absence of complications, pregnant women get 30 minutes or more of moderate exercise a day.

"I think our results offer a very positive message. If expectant mothers know that exercise is not only good for them but also may offer lifelong benefits for their babies, they may be more motivated to get moving."

Robert A. Waterland PhD

Previous rodent studies have shown that maternal voluntary exercise during pregnancy leads to metabolic changes in adult offspring. We set out to test whether maternal voluntary exercise during pregnancy also induces persistent changes in voluntary physical activity in the offspring. Adult C57BL/6J female mice were randomly assigned to be caged with an unlocked (U) or locked (L) running wheel before and during pregnancy. Maternal running behavior was monitored during pregnancy, and body weight, body composition, food intake, energy expenditure, total cage activity, and running wheel activity were measured in the offspring at various ages. U offspring were slightly heavier at birth, but no group differences in body weight or composition were observed at later ages (when mice were caged without access to running wheels). Consistent with our hypothesis, U offspring were more physically active as adults. This effect was observed earlier in female offspring (at sexual maturation). Remarkably, at 300 d of age, U females achieved greater fat loss in response to a 3-wk voluntary exercise program. Our findings show for the first time that maternal physical activity during pregnancy affects the offspring’s lifelong propensity for physical activity and may have important implications for combating the worldwide epidemic of physical inactivity and obesity.—Eclarinal, J. D., Zhu, S., Baker, M. S., Piyarathna, D. B., Coarfa, C., Fiorotto, M. L., Waterland, R. A. Maternal exercise during pregnancy promotes physical activity in adult offspring.

Authors: Jesse D. Eclarinal, Shaoyu Zhu, Maria S. Baker, Danthasinghe B. Piyarathna, Cristian Coarfa, and Marta L. Fiorotto, all from Baylor, also contributed to this work.

This work was funded by grants from the U.S. Department of Agriculture [CRIS 6250-51000-055 and CRIS 3092-5-001-059] and from the NIH [AR46308].
Return to top of page

Apr 1, 2016   Fetal Timeline   Maternal Timeline   News   News Archive   

Five-time national champion Alysia Montano ran a whopping 34 seconds slower than her
personal best in the 800-meter event at the U.S. Track and Field Championships at
Sacramento, CA, USA. Her excuse for those extra 34 seconds? She was 34 weeks pregnant
—that’s only six weeks away from labor and delivery!

Image Credit: LifeNews




Phospholid by Wikipedia